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Welding presentation

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    Welding presentation Welding presentation Presentation Transcript

    • Welding Inspector 4/23/2007 1 of 691
    • Main Responsibilities 1.1 • • • 4/23/2007 2 of 691
    • Personal Attributes 1.1 Important qualities that good Inspectors are expected to have are: Honesty • Integrity • Knowledge • Good communicator • Physical fitness • Good eyesight • 4/23/2007 3 of 691
    • Standard for Visual Inspection 1.1 Basic Requirements • • • 4/23/2007 4 of 691
    • Welding Inspection 4/23/2007 1.2 5 of 691
    • Welding Inspection 1.3 Aids to Visual Inspection (to BS EN 970) When access is restricted may use: • a mirrored boroscope • a fibre optic viewing system • welding gauges (for checking bevel angles, weld profile, fillet sizing, undercut depth) • dedicated weld-gap gauges and linear misalignment (high-low) gauges • straight edges and measuring tapes • magnifying lens (if magnification lens used it should have magnification between X2 to X5) 4/23/2007 6 of 691
    • Welding Inspectors Equipment 1.3 Measuring devices: • flexible tape, steel rule • Temperature indicating crayons • Welding gauges • Voltmeter • Ammeter • Magnifying glass • Torch / flash light • Gas flow-meter 4/23/2007 7 of 691
    • Welding Inspectors Gauges 10mm 10mm 1 2 G.A.L. G.A.L. 3 4 L S.T.D. 16mm S.T.D. 16mm 5 0 1/4 1/2 3/4 HI-LO Single Purpose Welding Gauge 6 1.3
    • Welding Inspectors Equipment 4/23/2007 1.3 9 of 691
    • Welding Inspection 1.3 4/23/2007 10 of 691
    • Typical Duties of a Welding Inspector 4/23/2007 1.5 11 of 691
    • Typical Duties of a Welding Inspector 4/23/2007 1.5 12 of 691
    • Typical Duties of a Welding Inspector 1.5 Before Welding Equipment: • all inspection equipment is in good condition & calibrated as necessary • all safety requirements are understood & necessary equipment available Materials: • can be identified & related to test certificates, traceability ! • are of correct dimensions • are in suitable condition (no damage/contamination) 4/23/2007 13 of 691
    • Typical Duties of a Welding Inspector 1.5 Before Welding Consumables: • in accordance with WPS’s • are being controlled in accordance with Procedure Weld Preparations: • comply with WPS/drawing • free from defects & contamination Welding Equipment: • in good order & calibrated as required by Procedure 4/23/2007 14 of 691
    • Typical Duties of a Welding Inspector 1.5 Before Welding Fit-up • complies with WPS • Number / size of tack welds to Code / good workmanship Pre-heat • if specified • minimum temperature complies with WPS 4/23/2007 15 of 691
    • Typical Duties of a Welding Inspector 4/23/2007 1.5 16 of 691
    • Typical Duties of a Welding Inspector 1.6 During Welding Welding consumables • in accordance with WPS • in suitable condition • controlled issue and handling Welding Parameters • current, voltage & travel speed – as WPS Root runs • if possible, visually inspect root before single-sided welds are filled up 4/23/2007 17 of 691
    • Typical Duties of a Welding Inspector 1.6 During Welding Inter-run cleaning in accordance with an approved method (& back gouging) to good workmanship standard Distortion control • welding is balanced & over-welding is avoided 4/23/2007 18 of 691
    • Typical Duties of a Welding Inspector 1.6 • • • • • • 4/23/2007 19 of 691
    • Typical Duties of a Welding Inspector 1.6 After Welding Repairs • monitor repairs to ensure compliance with Procedure, ensure NDT after repairs is completed • PWHT • monitor for compliance with Procedure • check chart records confirm Procedure compliance Pressure / Load Test • ensure test equipment is suitably calibrated • monitor to ensure compliance with Procedure • ensure all records are available 4/23/2007 20 of 691
    • Typical Duties of a Welding Inspector 1.6 After Welding Documentation • ensure any modifications are on ‘as-built’ drawings • ensure all required documents are available • Collate / file documents for manufacturing records • Sign all documentation and forward it to QC department. 4/23/2007 21 of 691
    • Summary of Duties • Observe To observe all relevant actions related to weld quality throughout production. • Record To record, or log all production inspection points relevant to quality, including a final report showing all identified imperfections • Compare To compare all recorded information with the acceptance criteria and any other relevant clauses in the applied application standard 4/23/2007 22 of 691
    • Welding Inspector Terms & Definitions Section 2 4/23/2007 23 of 691
    • Welding Terminology & Definitions 2.1 • • • 4/23/2007 24 of 691
    • Welding Terminology & Definitions 2.1 What is a Joint? • The junction of members or the edges of members that are to be joined or have been joined (AWS) • A configuration of members (BS499) 4/23/2007 25 of 691
    • Joint Terminology 2.2 4/23/2007 26 of 691
    • Welded Butt Joints 2.2 ________ __ __________ 4/23/2007 27 of 691
    • Welded Tee Joints 2.2 _________ _________ 4/23/2007 28 of 691
    • Weld Terminology 2.3 4/23/2007
    • Butt Preparations – Sizes 2.4 Partial Penetration Butt Weld Actual Throat Thickness Design Throat Thickness Full Penetration Butt Weld Design Throat Thickness 4/23/2007 Actual Throat Thickness 30 of 691
    • Weld Zone Terminology 2.5 Face A B Weld metal Heat Affected Zone Weld Boundary C 4/23/2007 D 31 of 691
    • Weld Zone Terminology 2.5 Weld cap width Actual Throat Thickness Design Throat Thickness Excess Root Penetration 4/23/2007 32 of 691
    • Heat Affected Zone (HAZ) 2.5 4/23/2007 33 of 691
    • Joint Preparation Terminology 2.7 4/23/2007 34 of 691
    • Joint Preparation Terminology Angle of bevel 4/23/2007 2.8 & 2.9 Angle of bevel 35 of 691
    • Single Sided Butt Preparations 4/23/2007 2.10 36 of 691
    • Double Sided Butt Preparations 2.11 4/23/2007 37 of 691
    • Weld Preparation 4/23/2007 38 of 691
    • Butt Weld - Toe Blend 4/23/2007 39 of 691
    • Fillet Weld Features 4/23/2007 2.13 40 of 691
    • Fillet Weld Throat Thickness 4/23/2007 2.13 41 of 691
    • Deep Penetration Fillet Weld Features 2.13 4/23/2007 42 of 691
    • Fillet Weld Sizes 2.14 Calculating Throat Thickness from a known Leg Length: Design Throat Thickness = Leg Length x 0.7 Question: The Leg length is 14mm. What is the Design Throat? Answer: 14mm x 0.7 = 10mm Throat Thickness 4/23/2007 43 of 691
    • Fillet Weld Sizes 2.14 Calculating Leg Length from a known Design Throat Thickness: Leg Length = Design Throat Thickness x 1.4 Question: The Design Throat is 10mm. What is the Leg length? Answer: 10mm x 1.4 = 14mm Leg Length 4/23/2007 44 of 691
    • Features to Consider 2 2.14 Importance of Fillet Weld Leg Length Size 4/23/2007 45 of 691
    • Fillet Weld Profiles 4/23/2007 2.15 47 of 691
    • Fillet Features to Consider 2.15 EFFECTIVE THROAT THICKNESS “a” = Nominal throat thickness a “s” = Effective throat thickness s Deep penetration fillet welds from high heat input welding process MAG, FCAW & SAW etc 4/23/2007 48 of 691
    • Welding Positions 2.17 PA 1G/1F Flat/Downhand PB 2F Horizontal-Vertical PC 2G Horizontal PD 4F PE 4G PF 3G/5G Vertical-Up PG 3G/5G Vertical-Down Horizontal-Vertical(Overhead) Overhead H-L045 6G InclinedPipe(Upwards) J-L045 6G InclinedPipe(Downwards) 4/23/2007 49 of 691
    • Welding Positions 2.17 ISO 4/23/2007 50 of 691
    • Welding position designation 2.17 Butt welds in plate (see ISO 6947) Flat - PA Overhead - PE Vertical up - PF Vertical down - PG 4/23/2007 Horizontal - PC 51 of 691
    • Welding position designation 2.17 Butt welds in pipe (see ISO 6947) Flat - PA axis: horizontal pipe: rotated H-L045 Vertical up - PF Vertical down - PG axis: horizontal pipe: fixed J-L045 axis: horizontal pipe: fixed Horizontal - PC axis: inclined at 45° axis: inclined at 45° axis: vertical pipe: fixed pipe: fixed pipe: fixed 4/23/2007 52 of 691
    • Welding position designation 2.17 Fillet welds on plate (see ISO 6947) Flat - PA Horizontal - PB Vertical up - PF 4/23/2007 Overhead - PD Vertical down - PG 53 of 691
    • Welding position designation 2.17 Fillet welds on pipe (see ISO 6947) Flat - PA Horizontal - PB Overhead - PD axis: inclined at 45° pipe: rotated axis: vertical pipe: fixed axis: vertical pipe: fixed Horizontal - PB Vertical up - PF Vertical down - PG axis: horizontal pipe: rotated 4/23/2007 axis: horizontal pipe: fixed axis: horizontal pipe: fixed 54 of 691
    • Plate/Fillet Weld Positions 4/23/2007 2.17 55 of 691
    • 4/23/2007 56 of 691
    • Welding Inspector Welding Imperfections Section 3 4/23/2007 58 of 691
    • Welding Imperfections 3.1 • • 4/23/2007 59 of 691
    • Welding Imperfections 4/23/2007 3.1 60 of 691
    • Welding Imperfections 4/23/2007 3.1 61 of 691
    • Welding imperfections classification 3.1 Cracks 4/23/2007 62 of 691
    • Cracks 3.1 Cracks that may occur in welded materials are caused generally by many factors and may be classified by shape and position. Note: Cracks are classed as Planar Defects. 4/23/2007 63 of 691
    • Cracks 4/23/2007 3.1 64 of 691
    • Cracks 4/23/2007 3.1 65 of 691
    • Cracks 3.2 Main Crack Types • • • • 4/23/2007 Solidification Cracks Hydrogen Induced Cracks Lamellar Tearing Reheat cracks 66 of 691
    • Cracks 3.2 Solidification Cracking • Occurs during weld solidification process • Steels with high sulphur impurities content (low ductility at elevated temperature) • Occur longitudinally down centre of weld 4/23/2007 67 of 691
    • Cracks 3.3 Hydrogen Induced Cold Cracking • Hydrogen enters weld via welding arc mainly as result of contaminated electrode or preparation • Hydrogen diffuses out into parent metal on cooling • Cracking developing most likely in HAZ 4/23/2007 68 of 691
    • Lamellar Tearing 3.5 • Location: Parent metal • Steel Type: Any steel type possible • Susceptible Microstructure: Poor through thickness ductility • Lamellar tearing has a step like appearance due to the solid inclusions in the parent material (e.g. sulphides and silicates) linking up under the influence of welding stresses • Low ductile materials in the short transverse direction containing high levels of impurities are very susceptible to lamellar tearing • It forms when the welding stresses act in the short transverse direction of the material (through thickness direction) 4/23/2007 69 of 691
    • Gas Cavities 4/23/2007 3.6 70 of 691
    • Gas Cavities 3.7 Porosity Root piping 4/23/2007 71 of 691
    • Gas Cavities 4/23/2007 3.8 72 of 691
    • Weld crater Crater pipe 4/23/2007 73 of 691
    • Crater cracks (Star cracks) • • Crater pipe • 4/23/2007
    • Solid Inclusions 3.10 Slag inclusions are defined as a non-metallic inclusion caused by some welding process
    • Solid Inclusions 4/23/2007 3.11 76 of 691
    • Welding Imperfections 3.13 • welding current too low • bevel angle too steep • root face too large (single-sided weld) • root gap too small (single-sided weld) • incorrect electrode angle • linear misalignment • welding speed too high • welding process related – particularly dip-transfer GMAW • flooding the joint with too much weld metal (blocking Out) 4/23/2007 77 of 691
    • Lack of Fusion 3.13
    • 4/23/2007 79 of 691
    • 4/23/2007 81 of 691
    • Undercut 4/23/2007 3.18 82 of 691
    • Surface and Profile 3.19
    • Surface and Profile 4/23/2007 3.19 84 of 691
    • 4/23/2007 85 of 691
    • Overlap 4/23/2007 3.21 86 of 691
    • Overlap 4/23/2007 3.21 87 of 691
    • Set-Up Irregularities 4/23/2007 3.22 88 of 691
    • Set-Up Irregularities 4/23/2007 3.22 89 of 691
    • Set-Up Irregularities 4/23/2007 3.22 90 of 691
    • 4/23/2007 91 of 691
    • 4/23/2007 92 of 691
    • 4/23/2007 93 of 691
    • Weld Root Imperfections 4/23/2007 3.24 94 of 691
    • • • • • 4/23/2007 95 of 691
    • Weld Root Imperfections 4/23/2007 3.25 96 of 691
    • • • • 4/23/2007 97 of 691
    • 4/23/2007 98 of 691
    • Miscellaneous Imperfections 3.27 • • • • • 4/23/2007 99 of 691
    • Mechanical Damage 3.28 Mechanical damage can be defined as any surface material damage cause during the manufacturing process. 4/23/2007 100 of 691
    • Mechanical Damage 4/23/2007 3.28 101 of 691
    • Welding Inspector Destructive Testing Section 4 4/23/2007 102 of 691
    • Qualitative and Quantitative Tests 4.1 The following mechanical tests have units and are termed quantitative tests to measure Mechanical Properties • Tensile tests (Transverse Welded Joint, All Weld Metal) • Toughness testing (Charpy, Izod, CTOD) • Hardness tests (Brinell, Rockwell, Vickers) The following mechanical tests have no units and are termed qualitative tests for assessing joint quality • Macro testing • Bend testing • Fillet weld fracture testing • Butt weld nick-break testing 4/23/2007 104 of 691
    • Mechanical Test Samples 4.1
    • Destructive Testing 4.1 4/23/2007 106 of 691
    • Definitions 4/23/2007 107 of 691
    • Definitions
    • Definitions 4/23/2007 109 of 691
    • Definitions 4/23/2007 110 of 691
    • Definitions 4/23/2007 111 of 691
    • Transverse Joint Tensile Test 4.2 Weld on plate Weld on pipe 4/23/2007 Multiple cross joint specimens 112 of 691
    • Tensile Test 4/23/2007 4.3 113 of 691
    • STRA (Short Transverse Reduction Area) For materials that may be subject to Lamellar Tearing 4/23/2007 114 of 691
    • UTS Tensile test 4/23/2007 4.4 115 of 691
    • Charpy V-Notch Impact Test 4.5 • • • • • • • • 4/23/2007 116 of 691
    • Ductile / Brittle Transition Curve 4.6 4/23/2007
    • Comparison Charpy Impact Test Results 4.6 4/23/2007 118 of 691
    • Charpy V-notch impact test specimen 4.7 4/23/2007 119 of 691
    • Charpy V-Notch Impact Test 4.8 4/23/2007 120 of 691
    • Charpy Impact Test 4/23/2007 4.9 121 of 691
    • Hardness Testing 4.10 122 of 691
    • Hardness Testing 4.10 • • • • • • 4/23/2007 123 of 691
    • Vickers Hardness Test 4/23/2007 4.11 124 of 691
    • Vickers Hardness Test Machine 4/23/2007 4.11 125 of 691
    • Brinell Hardness Test 4.11 Ø=10mm steel ball 4/23/2007 126 of 691
    • Rockwell Hardness Test Ø=1.6mm steel ball 4/23/2007 120 Diamond Cone 127 of 691
    • Hardness Testing 4.12 Hardness specimens can also be used for CTOD samples 4/23/2007 128 of 691
    • Fatigue Fracture 4/23/2007 4.13 130 of 691
    • Fatigue Fracture 4/23/2007 4.13 131 of 691
    • Fatigue Fracture Precautions against Fatigue Cracks • Toe grinding, profile grinding. • The elimination of poor profiles • The elimination of partial penetration welds and weld defects • Operating conditions under the materials endurance limits • The elimination of notch effects e.g. mechanical damage cap/root undercut • The selection of the correct material for the service conditions of the component 4/23/2007 132 of 691
    • Fatigue Fracture Fatigue fracture occurs in structures subject to repeated application of tensile stress. Crack growth is slow (in same cases, crack may grow into an area of low stress and stop without failure). 4/23/2007 133 of 691
    • Fatigue Fracture • Crack growth is slow • It initiate from stress concentration points • load is considerably below the design or yield stress level • The surface is smooth • The surface is bounded by a curve • Bands may sometimes be seen on the smooth surface –”beachmarks”. They show the progress of the crack front from the point of origin • Final fracture will usually take the form of gross yielding (as the maximum stress in the remaining ligament increase!) • Fatigue crack need initiation + propagation periods 4/23/2007 135 of 691
    • Bend Tests 4.15 • • Root bend Side bend Side bend tests are normally carried out on welds over 12mm in thickness 4/23/2007 136 of 691
    • Bending test 4.16 Types of bend test for welds (acc. BS EN 910): 4/23/2007 137 of 691
    • Fillet Weld Fracture Tests 4.17 Object of test: • To break open the joint through the weld to permit examination of the fracture surfaces • Specimens are cut to the required length • A saw cut approximately 2mm in depth is applied along the fillet welds length • Fracture is usually made by striking the specimen with a single hammer blow • Visual inspection for defects 4/23/2007 138 of 691
    • Fillet Weld Fracture Tests 4/23/2007 4.17 139 of 691
    • Fillet Weld Fracture Tests 4/23/2007 4.17 140 of 691
    • Nick-Break Test 4.18 Object of test: • To permit evaluation of any weld defects across the fracture surface of a butt weld. •Specimens are cut transverse to the weld •A saw cut approximately 2mm in depth is applied along the welds root and cap •Fracture is usually made by striking the specimen with a single hammer blow •Visual inspection for defects 4/23/2007 141 of 691
    • Nick-Break Test 4/23/2007 4.18 142 of 691
    • Nick Break Test 4/23/2007 4.18 143 of 691
    • We test welds to establish minimum levels of mechanical properties, and soundness of the welded joint We divide tests into Qualitative & Quantitative methods: Quantitative: (Have units/numbers) Qualitative: (Have no units/numbers) To measure mechanical properties For assessing joint quality Hardness (VPN & BHN) Macro tests Toughness (Joules & ft.lbs) Bend tests Strength (N/mm2 & PSI, MPa) Fillet weld fracture tests Ductility / Elongation (E%) Butt Nick break tests 4/23/2007 144 of 691
    • Welding Inspector WPS – Welder Qualifications Section 5 4/23/2007 145 of 691
    • 4/23/2007 146 of 691
    • Welding Procedures 5.1 Producing a welding procedure involves: • Planning the tasks • Collecting the data • Writing a procedure for use of for trial • Making a test welds • Evaluating the results • Approving the procedure • Preparing the documentation 4/23/2007 147 of 691
    • Welding Procedures 5.2 • • • • • 4/23/2007 148 of 691
    • The welding engineer writes qualified Welding Procedure Specifications (WPS) for production welding Production welding conditions must remain within the range of qualification allowed by the WPQR 4/23/2007 149 of 691
    • 5.3 4/23/2007 150 of 691
    • 5.3 4/23/2007 151 of 691
    • 4/23/2007 152 of 691
    • Welding Procedures 5.3 Components of a welding procedure Parent material • Type (Grouping) • Thickness • Diameter (Pipes) • Surface condition) Welding process • Type of process (MMA, MAG, TIG, SAW etc) • Equipment parameters • Amps, Volts, Travel speed Welding Consumables • Type of consumable/diameter of consumable • Brand/classification • Heat treatments/ storage 4/23/2007 153 of 691
    • Welding Procedures 5.3 Components of a welding procedure Joint design •Edge preparation •Root gap, root face •Jigging and tacking •Type of baking Welding Position •Location, shop or site •Welding position e.g. 1G, 2G, 3G etc •Any weather precaution Thermal heat treatments •Preheat, temps •Post weld heat treatments e.g. stress relieving 4/23/2007 154 of 691
    • Welding Procedures 4/23/2007 5.3 155 of 691
    • Welding Procedures 4/23/2007 156 of 691
    • Example: Welding Procedure Specification (WPS) 4/23/2007 157 of 691
    • Welder Qualification 4/23/2007 5.4 158 of 691
    • 4/23/2007 159 of 691
    • 4/23/2007 160 of 691
    • Welder Qualification • • • • • • • • • • • • • • 5.10 Welders name and identification number Date of test and expiry date of certificate Standard/code e.g. BS EN 287 Test piece details Welding process. Welding parameters, amps, volts Consumables, flux type and filler classification details Sketch of run sequence Welding positions Joint configuration details Material type qualified, pipe diameter etc Test results, remarks Test location and witnessed by Extent (range) of approval 4/23/2007 165 of 691
    • Welding Inspector Materials Inspection Section 6 4/23/2007 167 of 691
    • Material Inspection One of the most important items to consider is Traceability. The materials are of little use if we can not, by use of an effective QA system trace them from specification and purchase order to final documentation package handed over to the Client. All materials arriving on site should be inspected for: • Size / dimensions • Condition • Type / specification In addition other elements may need to be considered depending on the materials form or shape 4/23/2007 168 of 691
    • Pipe Inspection We inspect the condition (Corrosion, Damage, Wall thickness, Laminations & Seam) Specification Welded seam LP5 Size Other checks may need to be made such as: distortion tolerance, number of plates and storage. 4/23/2007 169 of 691
    • Plate Inspection We inspect the condition (Corrosion, Mechanical damage, Laps, Bands & Laminations) Specification 5L Size Other checks may need to be made such as: distortion tolerance, number of plates and storage. 4/23/2007 170 of 691
    • 4/23/2007 171 of 691
    • Lapping 4/23/2007 172 of 691
    • Lamination 4/23/2007 173 of 691
    • 4/23/2007 174 of 691
    • Welding Inspector Codes & Standards Section 7 4/23/2007 175 of 691
    • Codes & Standards The 3 agencies generally identified in a code or standard: The customer, or client The manufacturer, or contractor The 3rd party inspection, or clients representative Codes often do not contain all relevant data, but may refer to other standards 4/23/2007 176 of 691
    • Welding Inspector Welding Symbols Section 8 4/23/2007 178 of 691
    • Weld symbols on drawings Advantages of symbolic representation: • simple and quick plotting on the drawing • does not over-burden the drawing • no need for additional view • gives all necessary indications regarding the specific joint to be obtained Disadvantages of symbolic representation: • used only for usual joints • requires training for properly understanding of symbols 4/23/2007 179 of 691
    • Weld symbols on drawings The symbolic representation includes: • an arrow line • a reference line • an elementary symbol The elementary symbol may be completed by: • a supplementary symbol • a means of showing dimensions • some complementary indications 180 of 691 4/23/2007
    • Dimensions a = Design throat thickness s = Depth of Penetration, Throat thickness z = Leg length (min material thickness) •In a fillet weld, the size of the weld is the leg length •In a butt weld, the size of the weld is based on the depth of the joint preparation 4/23/2007 181 of 691
    • 4/23/2007 182 of 691
    • Weld symbols on drawings 4/23/2007 183 of 691
    • Elementary Welding Symbols (BS EN ISO 22553 & AWS A2.4) Convention of the elementary symbols: Various categories of joints are characterised by an elementary symbol. The vertical line in the symbols for a fillet weld, single/double bevel butts and a J-butt welds must always be on the left side. Sketch 4/23/2007 184 of 691
    • Elementary Welding Symbols 185 of 691
    • Elementary Welding Symbols 186 of 691
    • ISO 2553 / BS EN 22553 Plug weld Resistance spot weld Resistance seam weld 4/23/2007 Square Butt weld Steep flanked Single-V Butt Surfacing 187 of 691
    • • • • 4/23/2007 188 of 691
    • 4/23/2007 189 of 691
    • • • • 4/23/2007 190 of 691
    • 4/23/2007 191 of 691
    • ISO 2553 / BS EN 22553 4/23/2007 192 of 691
    • ISO 2553 / BS EN 22553
    • ISO 2553 / BS EN 22553 4/23/2007 194 of 691
    • ISO 2553 / BS EN 22553 4/23/2007
    • ISO 2553 / BS EN 22553 a z 4/23/2007 s 196 of 691
    • ISO 2553 / BS EN 22553 4/23/2007 197 of 691
    • ISO 2553 / BS EN 22553 s6 6mm fillet weld s6 4/23/2007 198 of 691
    • ISO 2553 / BS EN 22553 4/23/2007 199 of 691
    • ISO 2553 / BS EN 22553 5 80 80 80 5 6 90 90 90 6 4/23/2007 200 of 691
    • ISO 2553 / BS EN 22553 6 80 80 80 6 8 90 90 90 8 4/23/2007 201 of 691
    • 4/23/2007 202 of 691
    • 4/23/2007 203 of 691
    • ISO 2553 / BS EN 22553 4/23/2007 204 of 691
    • ISO 2553 / BS EN 22553 4/23/2007 205 of 691
    • ISO 2553 / BS EN 22553 a z 4/23/2007 s 206 of 691
    • ISO 2553 / BS EN 22553 Complimentary Symbols 4/23/2007 207 of 691
    • ISO 2553 / BS EN 22553 4/23/2007 208 of 691
    • AWS A2.4 Welding Symbols 4/23/2007 209 of 691
    • AWS Welding Symbols 4/23/2007 210 of 691
    • AWS Welding Symbols 4/23/2007 211 of 691
    • AWS Welding Symbols 4/23/2007 212 of 691
    • AWS Welding Symbols 3rd Operation Sequence of Operations 2nd Operation 1st Operation FCAW 1(1-1/8) 1/8 60o 4/23/2007 213 of 691
    • AWS Welding Symbols RT Sequence of Operations MT MT 1(1-1/8) 4/23/2007 FCAW 1/8 60o 214 of 691
    • AWS Welding Symbols Dimensions- Leg Length 6 leg on member A 6/8 Member A 6 8 Member B 4/23/2007 215 of 691
    • Welding Inspector Intro To Welding Processes Section 9 4/23/2007 221 of 691
    • Welding Processes 4/23/2007 222 of 691
    • 4/23/2007 225 of 691
    • Monitoring Heat Input • Heat Input: The amount of heat generated in the welding arc per unit length of weld. Expressed in kilo Joules per millimetre length of weld (kJ/mm). Heat Input (kJ/mm)= Volts x Amps Travel speed(mm/s) x 1000 227 of 691 4/23/2007
    • Monitoring Heat Input Weld and weld pool temperatures 4/23/2007 228 of 691
    • Monitoring Heat Input 4/23/2007 229 of 691
    • Monitoring Heat Input • Monitoring Heat Input As Required by • BS EN ISO 15614-1:2004 • In accordance with EN 1011-1:1998 When impact requirements and/or hardness requirements are specified, impact test shall be taken from the weld in the highest heat input position and hardness tests shall be taken from the weld in the lowest heat input position in order to qualify for all positions 4/23/2007 230 of 691
    • Welding Inspector MMA Welding Section 10 4/23/2007 231 of 691
    • MMA - Principle of operation 4/23/2007 233 of 691
    • MMA welding Main features: • Shielding provided by decomposition of flux covering • Electrode consumable • Manual process Welder controls: • • • • Arc length Angle of electrode Speed of travel Amperage settings 4/23/2007 234 of 691
    • MMA Welding Variables 4/23/2007 237 of 691
    • 4/23/2007 239 of 691
    • MMA welding parameters Travel speed 4/23/2007 240 of 691
    • MMA welding parameters Type of current: • • • • • voltage drop in welding cables is lower with AC inductive looses can appear with AC if cables are coiled cheaper power source for AC no problems with arc blow with AC DC provides a more stable and easy to strike arc, especially with low current, better positional weld, thin sheet applications • welding with a short arc length (low arc voltage) is easier with DC, better mechanical properties • DC provides a smoother metal transfer, less spatter 4/23/2007 241 of 691
    • MMA welding parameters Welding current
    • MMA - Troubleshooting 4/23/2007 244 of 691
    • MMA Welding Consumables 4/23/2007 246 of 691
    • 4/23/2007 247 of 691
    • Manual Metal Arc Welding (MMA) • • • • • • • • • • 4/23/2007 248 of 691
    • Welding Inspector TIG Welding Section 11 4/23/2007 249 of 691
    • Tungsten Inert Gas Welding 4/23/2007 250 of 691
    • TIG - Principle of operation 4/23/2007 251 of 691
    • TIG Welding Variables 4/23/2007 254 of 691
    • ARC CHARACTERISTICS 4/23/2007 258 of 691
    • TIG torch set-up • Electrode extension 4/23/2007 263 of 691
    • Tungsten Electrodes 4/23/2007 265 of 691
    • Tungsten electrode types 4/23/2007 266 of 691
    • Tungsten electrode types 267 of 691
    • Tungsten electrode types black 4/23/2007 268 of 691
    • Tungsten electrode types white 4/23/2007 269 of 691
    • Electrode tip for DCEN
    • Electrode tip for AC DC -ve AC
    • TIG Welding Variables
    • Choosing the proper electrode 4/23/2007 273 of 691
    • Shielding gas requirements • Preflow and postflow 4/23/2007 275 of 691
    • TIG Welding Consumables Welding consumables for TIG: •Filler wires, Shielding gases, tungsten electrodes (nonconsumable). •Filler wires of different materials composition and variable diameters available in standard lengths, with applicable code stamped for identification •Steel Filler wires of very high quality, with copper coating to resist corrosion. •shielding gases mainly Argon and Helium, usually of highest purity (99.9%). 4/23/2007 278 of 691
    • Tungsten Inclusion May be caused by Thermal Shock of heating to fast and small fragments break off and enter the weld pool, so a “slope up” device is normally fitted to prevent this could be caused by touch down also. Most TIG sets these days have slopeup devices that brings the current to the set level over a short period of time so the tungsten is heated more slowly and gently 4/23/2007 279 of 691
    • Tungsten Inert Gas Welding Advantages Disadvantages • High quality • High skill factor required • Good control • Low deposition rate • All positions • Small consumable range • Lowest H2 process • High protection required • Minimal cleaning • Complex equipment • Autogenous welding • Low productivity (No filler material) • High ozone levels +HF • Can be automated 4/23/2007 281 of 691
    • Welding Inspector MIG/MAG Welding Section 12 4/23/2007 282 of 691
    • Gas Metal Arc Welding 4/23/2007 283 of 691
    • MIG/MAG - Principle of operation 4/23/2007 284 of 691
    • MIG/MAG process variables • Welding current •Increasing welding current •Increase in depth and width •Increase in deposition rate • Polarity 4/23/2007 286 of 691
    • MIG/MAG process variables • Arc voltage •Increasing arc voltage •Reduced penetration, increased width •Excessive voltage can cause porosity, spatter and undercut • Travel speed •Increasing travel speed •Reduced penetration and width, undercut 4/23/2007 287 of 691
    • Gas Metal Arc Welding 4/23/2007 289 of 691
    • MIG/MAG – shielding gases 4/23/2007 290 of 691
    • MIG/MAG shielding gases Ar Ar-He He CO2 Argon (Ar): higher density than air; low thermal conductivity the arc has a high energy inner cone; good wetting at the toes; low ionisation potential Helium (He): lower density than air; high thermal conductivity uniformly distributed arc energy; parabolic profile; high ionisation potential Carbon Dioxide (CO2): cheap; deep penetration profile; cannot support spray transfer; poor wetting; high spatter 4/23/2007 291 of 691
    • MIG/MAG Gas Metal Arc Welding Electrode orientation 295 of 691
    • MIG/MAG - metal transfer modes Set-up for dip transfer 4/23/2007 Set-up for spray transfer 299 of 691
    • 4/23/2007 315 of 691
    • MIG/MAG welding gun assembly 4/23/2007 316 of 691
    • Gas Metal Arc Welding 4/23/2007 318 of 691
    • 4/23/2007 322 of 691
    • WELDING PROCESS Flux Core Arc Welding (Not In The Training Manual) 4/23/2007 323 of 691
    • Flux cored arc welding 4/23/2007 324 of 691
    • “Outershield” - principle of operation 4/23/2007 325 of 691
    • “Innershield” - principle of operation 4/23/2007 326 of 691
    • ARC CHARACTERISTICS 4/23/2007 327 of 691
    • Flux cored arc welding 4/23/2007 329 of 691
    • FCAW - differences from MIG/MAG • usually operates in DCEP but some “Innershield” wires operates in DCEN • power sources need to be more powerful due to the higher currents • doesn't work in deep transfer mode • require knurled feed rolls 330 of 691
    • Backhand (“drag”) technique Advantages 4/23/2007 331 of 691
    • Forehand (“push”) technique Advantages 4/23/2007 332 of 691
    • FCAW advantages • • • • • • • less sensitive to lack of fusion requires smaller included angle compared to MMA high productivity all positional smooth bead surface, less danger of undercut basic types produce excellent toughness properties good control of the weld pool in positional welding especially with rutile wires • seamless wires have no torsional strain, twist free • ease of varying the alloying constituents • no need for shielding gas 4/23/2007 333 of 691
    • FCAW disadvantages • limited to steels and Ni-base alloys • slag covering must be removed • FCAW wire is more expensive on a weight basis than solid wires (exception: some high alloy steels) • for gas shielded process, the gaseous shield may be affected by winds and drafts • more smoke and fumes are generated compared with MIG/MAG • in case of Innershield wires, it might be necessary to break the wire for restart (due to the high amount of insulating slag formed at the tip of the wire) 4/23/2007 334 of 691
    • Welding Inspector Submerged Arc Welding Section 13 4/23/2007 336 of 691
    • • Submerged arc welding was developed in the Soviet Union during the 2nd world war for the welding of thick section steel. • The process is normally mechanized. • The process uses amps in the range of 100 to over2000, which gives a very high current density in the wire producing deep penetration and high dilution welds. • A flux is supplied separately via a flux hopper in the form of either fused or agglomerated. • The arc is not visible as it is submerged beneath the flux layer and no eye protection is required. 4/23/2007 337 of 691
    • SAW Principle of operation 4/23/2007 338 of 691
    • Principles of operation
    • Submerged Arc Welding - 4/23/2007 + 340 of 691
    • SAW process variables 4/23/2007 341 of 691
    • SAW process variables 4/23/2007 342 of 691
    • SAW operating variables 4/23/2007 343 of 691
    • SAW Consumables (Covered in detail in Section 14) 4/23/2007 344 of 691
    • SAW Consumables 4/23/2007 345 of 691
    • SAW equipment 4/23/2007 347 of 691
    • ARC CHARACTERISTICS Constant Voltage Characteristic Small change in voltage = large change in amperage OCV Large arc gap Small arc gap The self adjusting arc. Volts Amps 4/23/2007 348 of 691
    • SAW equipment • • Courtesy of ESAB AB • • 4/23/2007 Courtesy of ESAB AB 350 of 691
    • SAW operating variables 4/23/2007 352 of 691
    • SAW operating variables 4/23/2007 353 of 691
    • SAW operating variables 354 of 691
    • SAW operating variables 4/23/2007 355 of 691
    • SAW operating variables • 4/23/2007 356 of 691
    • SAW operating variables 4/23/2007 357 of 691
    • SAW operating variables 4/23/2007 358 of 691
    • SAW operating variables 4/23/2007 359 of 691
    • SAW technological variables
    • SAW technological variables Earth position + Direction of travel •welding towards earth produces backward arc blow •deep penetration •convex weld profile 4/23/2007 364 of 691
    • SAW technological variables + 4/23/2007 365 of 691
    • Weld backing 4/23/2007 366 of 691
    • Starting/finishing the weld 4/23/2007 367 of 691
    • SAW variants
    • SAW variants 4/23/2007 369 of 691
    • SAW variants
    • SAW variants 4/23/2007 372 of 691
    • SAW variants 4/23/2007 377 of 691
    • SAW variants 378 of 691
    • SAW variants 4/23/2007 379 of 691
    • SAW variants
    • Advantages of SAW 4/23/2007 382 of 691
    • 4/23/2007 384 of 691
    • Welding Inspector Welding Consumables Section 14 4/23/2007 385 of 691
    • BS EN 499 MMA Covered Electrodes Covered Electrode Yield Strength N/mm2 Toughness Chemical composition Flux Covering Weld Metal Recovery and Current Type Welding Position Hydrogen Content 4/23/2007 386 of 691
    • • • • • 4/23/2007 387 of 691
    • Welding Consumable Standards MIG/MAG (GMAW) TIG (GTAW) MMA (SMAW) • BS 2901: Filler wires • BS EN 499: Steel electrodes • BS EN 440: Wire electrodes • AWS A5.1 Non-alloyed steel • AWS A5.9: Filler wires electrodes • AWS A5.4 Chromium electrodes • AWS A5.5 Alloyed steel electrodes • BS EN 439: Shielding gases SAW • BS 4165: Wire and fluxes • BS EN 756: Wire electrodes • BS EN 760: Fluxes • AWS A5.17: Wires and fluxes 4/23/2007 388 of 691
    • Welding Consumable Gases 4/23/2007 389 of 691
    • Welding Consumables Each consumable is critical in respect to: • Size, (diameter and length) • Classification / Supplier • Condition • Treatments e.g. baking / drying • Handling and storage is critical for consumable control • Handling and storage of gases is critical for safety 4/23/2007 390 of 691
    • MMA Welding Consumables 4/23/2007 392 of 691
    • MMA Welding Consumables Welding consumables for MMA: • Consist of a core wire typically between 350-450mm in length and from 2.5mm - 6mm in diameter • The wire is covered with an extruded flux coating • The core wire is generally of a low quality rimming steel • The weld quality is refined by the addition of alloying and refining agents in the flux coating • The flux coating contains many elements and compounds that all have a variety of functions during welding 4/23/2007 393 of 691
    • MMA Welding Consumables 4/23/2007 394 of 691
    • EN 499-E 51 3 B 395 of 691
    • MMA Welding Consumables 4/23/2007 396 of 691
    • MMA Welding Consumables Cellulosic electrodes: • covering contains cellulose (organic material). • produce a gas shield high in hydrogen raising the arc voltage. • Deep penetration / fusion characteristics enables welding at high speed without risk of lack of fusion. • generates high level of fumes and H2 cold cracking. • Forms a thin slag layer with coarse weld profile. • not require baking or drying (excessive heat will damage electrode covering!). • Mainly used for stove pipe welding • hydrogen content is 80-90 ml/100 g of weld metal. 4/23/2007 397 of 691
    • MMA Welding Consumables 4/23/2007 398 of 691
    • MMA Welding Consumables Advantages: Disadvantages: • Deep penetration/fusion • High in hydrogen • Suitable for welding in all positions • High crack tendency • Fast travel speeds • High spatter contents • Large volumes of shielding gas • Low deposition rates • Rough weld appearance • Low control 4/23/2007 399 of 691
    • MMA Welding Consumables 4/23/2007 400 of 691
    • MMA Welding Consumables 4/23/2007 401 of 691
    • MMA Welding Consumables Advantages: Disadvantages: • Easy to use • High in hydrogen • Low cost / control • High crack tendency • Smooth weld profiles • Low strength • Slag easily detachable • Low toughness values • High deposition possible with the addition of iron powder 4/23/2007 402 of 691
    • MMA Welding Consumables Rutile Variants 4/23/2007 403 of 691
    • MMA Welding Consumables 4/23/2007 404 of 691
    • MMA Welding Consumables 4/23/2007 405 of 691
    • MMA Welding Consumables 4/23/2007 406 of 691
    • Advantages Disadvantages • High toughness values • High cost • Low hydrogen contents • High control • Low crack tendency • High welder skill required • Convex weld profiles • Poor stop / start properties 4/23/2007 407 of 691
    • BS EN 499 MMA Covered Electrodes 4/23/2007 408 of 691
    • BS EN 499 MMA Covered Electrodes Electrodes classified as follows: • E 35 - Minimum yield strength 350 N/mm2 Tensile strength 440 - 570 N/mm2 • E 38 - Minimum yield strength 380 N/mm2 Tensile strength 470 - 600 N/mm2 • E 42 - Minimum yield strength 420 N/mm2 Tensile strength 500 - 640 N/mm2 • E 46 - Minimum yield strength 460 N/mm2 Tensile strength 530 - 680 N/mm2 • E 50 - Minimum yield strength 500 N/mm2 Tensile strength 560 - 720 N/mm2 4/23/2007 409 of 691
    • AWS A5.1 Alloyed Electrodes 4/23/2007 411 of 691
    • AWS A5.5 Alloyed Electrodes 4/23/2007 412 of 691
    • 4/23/2007 413 of 691
    • Electrode efficiency 75-90% for usual electrodes 4/23/2007 414 of 691
    • Covered electrode treatment 4/23/2007
    • Covered electrode treatment
    • TIG Consumables 4/23/2007 417 of 691
    • TIG Welding Consumables Welding consumables for TIG: •Filler wires, Shielding gases, tungsten electrodes (nonconsumable). •Filler wires of different materials composition and variable diameters available in standard lengths, with applicable code stamped for identification •Steel Filler wires of very high quality, with copper coating to resist corrosion. •shielding gases mainly Argon and Helium, usually of highest purity (99.9%). 4/23/2007 418 of 691
    • TIG Welding Consumables 4/23/2007 419 of 691
    • Fusible Inserts 4/23/2007 420 of 691
    • Fusible Inserts 4/23/2007 421 of 691
    • Shielding gases for TIG welding Argon • low cost and greater availability • heavier than air - lower flow rates than Helium • low thermal conductivity - wide top bead profile • low ionisation potential - easier arc starting, better arc stability with AC, cleaning effect • for the same arc current produce less heat than helium reduced penetration, wider HAZ • to obtain the same arc arc power, argon requires a higher current - increased undercut 4/23/2007 423 of 691
    • Shielding gases for TIG welding Helium • costly and lower availability than Argon • lighter than air - requires a higher flow rate compared with argon (2-3 times) • higher ionisation potential - poor arc stability with AC, less forgiving for manual welding • for the same arc current produce more heat than argon increased penetration, welding of metals with high melting point or thermal conductivity • to obtain the same arc arc power, helium requires a lower current - no undercut 4/23/2007 424 of 691
    • Shielding gases for TIG welding Hydrogen • not an inert gas - not used as a primary shielding gas • increase the heat input - faster travel speed and increased penetration • better wetting action - improved bead profile • produce a cleaner weld bead surface • added to argon (up to 5%) - only for austenitic stainless steels and nickel alloys • flammable and explosive 4/23/2007 425 of 691
    • Shielding gases for TIG welding Nitrogen • not an inert gas • high availability - cheap • added to argon (up to 5%) - only for back purge for duplex stainless, austenitic stainless steels and copper alloys • not used for mild steels (age embritlement) • strictly prohibited in case of Ni and Ni alloys (porosity) 4/23/2007 426 of 691
    • MIG / MAG Consumables (Gases Covered previously) 4/23/2007 427 of 691
    • MIG/MAG Welding Consumables Welding consumables for MIG/MAG • Spools of Continuous electrode wires and shielding gases • variable spool size (1-15Kg) and Wire diameter (0.61.6mm) supplied in random or orderly layers • Basic Selection of different materials and their alloys as electrode wires. • Some Steel Electrode wires copper coating purpose is corrosion resistance and electrical pick-up • Gases can be pure CO2, CO2+Argon mixes and Argon+2%O2 mixes (stainless steels). 4/23/2007 428 of 691
    • MIG/MAG Welding Consumables 4/23/2007 429 of 691
    • Flux Core Wire Consumables (Not in training manual) 4/23/2007 433 of 691
    • Flux Core Wire Consumables Functions of metallic sheath: provide form stability to the wire serves as current transfer during welding 4/23/2007 Function of the filling powder: stabilise the arc add alloy elements produce gaseous shield produce slag add iron powder 434 of 691
    • Types of cored wire 435 of 691 • not sensitive to moisture pick-up • can be copper coated, better current transfer • thick sheath, good form stability, 2 roll drive feeding possible • difficult to manufacture 4/23/2007 • good resistance to moisture pick-up • can be copper coated • thick sheath • difficult to seal the sheath
    • Core elements and their function Aluminium - deoxidize & denitrify Calcium - provide shielding & form slag Carbon - increase hardness & strength Manganese - deoxidize & increase strength and toughness Molybdenum - increase hardness & strength Nickel - improve hardness, strength, toughness & corrosion resistance Potassium - stabilize the arc & form slag Silicon - deoxidize & form slag Sodium - stabilize arc & form slag Titanium - deoxidize, denitrify & form slag 4/23/2007 436 of 691
    • SAW Consumables 4/23/2007 437 of 691
    • SAW Consumables 4/23/2007 438 of 691
    • SAW Consumables 4/23/2007 439 of 691
    • SAW Consumables Baked at high temperature, glossy, hard and black in colour, cannot add ferro-manganese, non moisture absorbent and tends to be of the acidic type 4/23/2007 441 of 691
    • SAW Consumables 4/23/2007 442 of 691
    • SAW Consumables 4/23/2007 443 of 691
    • SAW Consumables Agglomerated Flux: Baked at a lower temperature, dull, irregularly shaped, friable, (easily crushed) can easily add alloying elements, moisture absorbent and tend to be of the basic type 4/23/2007 444 of 691
    • SAW Consumables 4/23/2007 445 of 691
    • SAW Consumables 4/23/2007 446 of 691
    • SAW Consumables 4/23/2007 447 of 691
    • SAW filler material 4/23/2007 448 of 691
    • SAW filler material 4/23/2007 449 of 691
    • SAW filler material 4/23/2007 450 of 691
    • Welding Inspector Non Destructive Testing Section 15 4/23/2007 452 of 691
    • Non-Destructive Testing A welding inspector should have a working knowledge of NDT methods and their applications, advantages and disadvantages. Four basic NDT methods • Radiographic inspection (RT) • Ultrasonic inspection (UT) • Magnetic particle inspection (MT) • Dye penetrant inspection (PT) 4/23/2007 453 of 691
    • • 4/23/2007 454 of 691
    • 4/23/2007 455 of 691
    • Radiographic Testing • • • • • 4/23/2007 456 of 691
    • Radiographic Testing 4/23/2007 457 of 691
    • Radiographic Testing 4/23/2007 458 of 691
    • Radiographic Testing Densitometer 4/23/2007 459 of 691
    • Radiographic Sensitivity 4/23/2007 460 of 691
    • Radiographic Sensitivity 4/23/2007 461 of 691
    • Radiographic Techniques 4/23/2007 462 of 691
    • Single Wall Single Image (SWSI) 4/23/2007 463 of 691
    • Single Wall Single Image Panoramic 4/23/2007 464 of 691
    • Double Wall Single Image (DWSI) 4/23/2007 465 of 691
    • Double Wall Single Image (DWSI) EN W10 4/23/2007 466 of 691
    • Double Wall Single Image (DWSI) 4/23/2007 467 of 691
    • Double Wall Double Image (DWDI) 4/23/2007 468 of 691
    • Double Wall Double Image (DWDI) 4 3 EN W10 1 2 ID MR12 4/23/2007
    • Double Wall Double Image (DWDI) 4 1 4/23/2007 3 2 470 of 691
    • 4/23/2007 471 of 691
    • 4/23/2007 472 of 691
    • Radiographic Testing
    • 4/23/2007 474 of 691
    • Radiographic Testing Comparison with Ultrasonic Examination DISADVANTAGES • health & safety hazard • not good for thick sections • high capital and relatively high running costs • not good for planar defects • X-ray sets not very portable • requires access to both sides of weld • frequent replacement of gamma source needed (half life) 475 of 691 4/23/2007
    • 4/23/2007 476 of 691
    • Ultrasonic Testing 4/23/2007 477 of 691
    • Ultrasonic Testing 4/23/2007 478 of 691
    • Ultrasonic Testing 0 4/23/2007 10 20 30 40 50 479 of 691
    • Ultrasonic Testing 480 of 691
    • Ultrasonic Testing initial pulse defect echo defect 0 10 20 30 40 50 ½ Skip CRT Display initial pulse defect echo defect Full Skip 4/23/2007 0 10 20 30 40 50 CRT Display 481 of 691
    • Ultrasonic Testing 4/23/2007 482 of 691
    • 483 of 691
    • Ultrasonic Testing Comparison with Radiography DISADVANTAGES • no permanent record (with standard equipment) • not suitable for very thin joints <8mm • reliant on operator interpretation • not good for sizing Porosity • good/smooth surface profile needed • not suitable for coarse grain materials (e.g., castings) • Ferritic Materials (with standard equipment) 484 of 691 4/23/2007
    • 4/23/2007 485 of 691
    • Magnetic Particle Testing Main features: • • • • • Surface and slight sub-surface detection Relies on magnetization of component being tested Only Ferro-magnetic materials can be tested A magnetic field is introduced into a specimen being tested Methods of applying a magnetic field, yoke, permanent magnet, prods and flexible cables. • Fine particles of iron powder are applied to the test area • Any defect which interrupts the magnetic field, will create a leakage field, which attracts the particles • Any defect will show up as either a dark indication or in the case of fluorescent particles under UV-A light a green/yellow indication 4/23/2007 486 of 691
    • Magnetic Particle Testing Electro-magnet (yoke) DC or AC Prods DC or AC 4/23/2007 487 of 691
    • Magnetic Particle Testing 4/23/2007 488 of 691
    • Magnetic Particle Testing 4/23/2007 489 of 691
    • Magnetic Particle Testing 4/23/2007 490 of 691
    • Magnetic Particle Testing 4/23/2007 491 of 691
    • 492 of 691
    • 4/23/2007 493 of 691
    • Penetrant Testing Main features: • Detection of surface breaking defects only. • This test method uses the forces of capillary action • Applicable on any material type, as long they are non porous. • Penetrants are available in many different types: • Water washable contrast • Solvent removable contrast • Water washable fluorescent • Solvent removable fluorescent • Post-emulsifiable fluorescent 4/23/2007 494 of 691
    • Penetrant Testing 4/23/2007 495 of 691
    • Penetrant Testing 4/23/2007 496 of 691
    • Penetrant Testing 4/23/2007 497 of 691
    • Penetrant Testing 4/23/2007 498 of 691
    • Penetrant Testing 4/23/2007 499 of 691
    • Penetrant Testing 4/23/2007
    • Penetrant Testing Advantages Disadvantages • • • • • Surface breaking defect only • little indication of depths • Penetrant may contaminate component • Surface preparation critical • Post cleaning required • Potentially hazardous chemicals • Can not test unlimited times • Temperature dependant Simple to use Inexpensive Quick results Can be used on any nonporous material • Portability • Low operator skill required 4/23/2007 501 of 691
    • 502 of 691
    • Welding Inspector Weld Repairs Section 16 4/23/2007 503 of 691
    • Weld Repairs Weld repairs can be divided into 2 specific areas: •Production repairs •In service repairs 4/23/2007 504 of 691
    • Weld Repairs A weld repair can be a relatively straight forward activity, but in many instances it is quite complex, and various engineering disciplines may need to be involved to ensure a successful outcome. •Analysis of the defect types may be carried out by the Q/C department to discover the likely reason for their occurrence, (Material/Process or Skill related). 4/23/2007 505 of 691
    • Weld Repairs A weld repair may be used to improve weld profiles or extensive metal removal: •Repairs to fabrication defects are generally easier than repairs to service failures because the repair procedure may be followed •The main problem with repairing a weld is the maintenance of mechanical properties •During the inspection of the removed area prior to welding the inspector must ensure that the defects have been totally removed and the original joint profile has been maintained as close as possible 4/23/2007 506 of 691
    • Weld Repairs In the event of repair, it is required: • Authorization and procedure for repair • Removal of material and preparation for repair • Monitoring of repair Weld • Testing of repair - visual and NDT 4/23/2007 507 of 691
    • Weld Repairs There are a number of key factors that need to be considered before undertaking any repair: • The most important - is it financially worthwhile? • Can structural integrity be achieved if the item is repaired? • Are there any alternatives to welding? • What caused the defect and is it likely to happen again? • How is the defect to be removed and what welding process is to be used? • What NDE is required to ensure complete removal of the defect? • Will the welding procedures require approval/re-approval? 4/23/2007 508 of 691
    • Weld Repairs • Cleaning the repair area, (removal of paint, grease, etc) • A detailed assessment to find out the extremity of the defect. This may involve the use of a surface or sub surface NDE method. • Once established the excavation site must be clearly identified and marked out. • An excavation procedure may be required (method used i.e. grinding, arc-air gouging, preheat requirements etc). • NDE should be used to locate the defect and confirm its removal. • A welding repair procedure/method statement with the appropriate welding process, consumable, technique, controlled heat input and interpass temperatures etc will need to be approved. 4/23/2007 509 of 691
    • Weld Repairs • Use of approved welders. • Dressing the weld and final visual. • A NDT procedure/technique prepared and carried out to ensure that the defect has been successfully removed and repaired. • Any post repair heat treatment requirements. • Final NDT procedure/technique prepared and carried out after heat treatment requirements. • Applying protective treatments (painting etc as required). • (*Appropriate’ means suitable for the alloys being repaired and may not apply in specific situations) 4/23/2007 510 of 691
    • Weld Repairs • What will be the effect of welding distortion and residual stress? • Will heat treatment be required? • What NDE is required and how can acceptability of the repair be demonstrated? • Will approval of the repair be required – if yes, how and by whom? 4/23/2007 511 of 691
    • Production Weld Repairs 4/23/2007 512 of 691
    • Weld Repairs The specification or procedure will govern how the defective areas are to be removed. The method of removal may be: •Grinding •Chipping •Machining •Filing •Oxy-Gas gouging •Arc air gouging 4/23/2007 513 of 691
    • Defect Excavation 4/23/2007 514 of 691
    • Arc-air gouging features 515 of 691
    • Production Weld Repairs Production Repairs •are usually identified during production inspection •evaluation of the reports is usually carried out by the Welding Inspector, or NDT operator 4/23/2007 516 of 691
    • Production Weld Repairs Plan View of defect 4/23/2007 517 of 691
    • Production Weld Repairs Side View of defect excavation W D Side View of repair welding 4/23/2007 518 of 691
    • In Service Weld Repairs In service repairs • Can be of a very complex nature, as the component is very likely to be in a different welding position and condition than it was during production • It may also have been in contact with toxic, or combustible fluids hence a permit to work will need to be sought prior to any work being carried out • The repair welding procedure may look very different to the original production procedure due to changes in these elements. 4/23/2007 519 of 691
    • In Service Weld Repairs Other factors to be taken into consideration: Effect of heat on any surrounding areas of the component i.e. electrical components, or materials that may become damaged by the repair procedure. This may also include difficulty in carrying out any required pre or post welding heat treatments and a possible restriction of access to the area to be repaired. For large fabrications it is likely that the repair must also take place on site and without a shut down of operations, which may bring other elements that need to be considered. 4/23/2007 520 of 691
    • Weld Repairs • Is welding the best method of repair? • Is the repair really like earlier repairs? • What is the composition and weldability of the base metal? • What strength is required from the repair? • Can preheat be tolerated? • Can softening or hardening of the HAZ be tolerated? • Is PWHT necessary and practicable? • Will the fatigue resistance of the repair be adequate? • Will the repair resist its environment? • Can the repair be inspected and tested? 521 of 691 4/23/2007
    • Weld repair related problems • heat from welding may affect dimensional stability and/or mechanical properties of repaired assembly • due to heat from welding, YS goes down, danger of collapse • filler materials used on dissimilar welds may lead to galvanic corrosion • local preheat may induce residual stresses • cost of weld metal deposited during a weld joint repair can reach up to 10 times the original weld metal cost! 4/23/2007 522 of 691
    • Welding Inspector Residual Stress & Distortion Section 17 4/23/2007 523 of 691
    • Residual stress 4/23/2007 524 of 691
    • Residual Stresses 4/23/2007 525 of 691
    • Stresses 4/23/2007 526 of 691
    • Stresses 4/23/2007 527 of 691
    • Stresses 4/23/2007 528 of 691
    • Residual Stresses 4/23/2007 529 of 691
    • Residual stress 4/23/2007 530 of 691
    • Residual stress 4/23/2007 531 of 691
    • Summary 4/23/2007 532 of 691
    • Summary 4/23/2007 533 of 691
    • Types of distortion Angular distortion 4/23/2007 534 of 691
    • Distortion
    • Distortion 4/23/2007 536 of 691
    • Distortion 4/23/2007 537 of 691
    • Distortion Factors affecting distortion: 4/23/2007 538 of 691
    • Factors affecting distortion Parent material properties: 4/23/2007 539 of 691
    • Factors affecting distortion Joint design: 4/23/2007 540 of 691
    • Factors affecting distortion Welding sequence: 4/23/2007 541 of 691
    • Distortion prevention Distortion prevention by pre-setting 4/23/2007 542 of 691
    • Distortion 4/23/2007 543 of 691
    • Distortion prevention Distortion prevention by pre-bending using strongbacks and wedges 4/23/2007 544 of 691
    • Distortion 4/23/2007 545 of 691
    • Distortion prevention Distortion prevention by restraint techniques 4/23/2007 546 of 691
    • Distortion prevention Distortion prevention by restraint techniques 4/23/2007 547 of 691
    • Distortion prevention 4/23/2007
    • Distortion prevention Distortion prevention by design 4/23/2007 549 of 691
    • Distortion prevention 4/23/2007 550 of 691
    • Distortion prevention Distortion prevention by design 4/23/2007 551 of 691
    • Distortion prevention 4/23/2007 552 of 691
    • Distortion prevention Distortion prevention by fabrication techniques 4/23/2007 555 of 691
    • Distortion prevention Distortion prevention by welding procedure 4/23/2007 556 of 691
    • Distortion prevention Distortion prevention by welding procedure 4/23/2007 557 of 691
    • Distortion prevention Distortion prevention by welding procedure 4/23/2007 558 of 691
    • Distortion prevention 4/23/2007 559 of 691
    • Distortion prevention Distortion - Best practice for fabrication corrective techniques 4/23/2007 560 of 691
    • Distortion corrective techniques Distortion - mechanical corrective techniques 4/23/2007 561 of 691
    • Distortion corrective techniques Distortion - Best practice for mechanical corrective techniques - clear 562 of 691
    • Distortion corrective techniques Distortion - thermal corrective techniques 4/23/2007 563 of 691
    • Distortion corrective techniques Distortion - thermal corrective techniques 4/23/2007 564 of 691
    • Distortion corrective techniques Distortion - thermal corrective techniques General guidelines: •Length of wedge = two-thirds of the plate width •Width of wedge (base) = one sixth of its length (base to apex) 4/23/2007 565 of 691
    • Distortion corrective techniques Distortion - thermal corrective techniques •use spot heating to remove buckling in thin sheet structures •other than in spot heating of thin panels, use a wedge-shaped heating technique •use line heating to correct angular distortion in plate •restrict the area of heating to avoid over-shrinking the component •limit the temperature to 60° to 650°C (dull red heat) in steels to prevent metallurgical damage •in wedge heating, heat from the base to the apex of the wedge, penetrate evenly through the plate thickness and maintain an even temperature 4/23/2007 566 of 691
    • Welding Inspector Heat Treatment Section 18 4/23/2007 567 of 691
    • Heat Treatment
    • Heat Treatments Many metals must be given heat treatment before and after welding. The inspector’s function is to ensure that the treatment is given correctly in accordance with the specification or as per the details supplied. Types of heat treatment available: •Preheat •Annealing •Normalising •Quench Hardening •Temper •Stress Relief 4/23/2007 569 of 691
    • Heat Treatments Pre-heat treatments • are used to increase weldability, by reducing sudden reduction of temperature, and control expansion and contraction forces during welding Post weld heat treatments • are used to change the properties of the weld metal, controlling the formation of crystalline structures 4/23/2007 570 of 691
    • Post Weld Heat Treatments A B (A) Normalised (B) Fully Annealed (C) Water-quenched (D) Water-quenched & tempered C 4/23/2007 D 572 of 691
    • Post Weld Heat Treatments The inspector, in general, should ensure that: • Equipment is as specified • Temperature control equipment is in good condition • Procedures as specified, is being used e.g. o Method of application o Rate of heating and cooling o Maximum temperature o Soak time o Temperature measurement (and calibration) • DOCUMENTATION AND RECORDS 4/23/2007 573 of 691
    • Post Weld Heat Treatment Cycle Time 4/23/2007 575 of 691
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    • Heat Treatment Recommendations • Provide adequate support (low YS at high temperature!) • Control heating rate to avoid uneven thermal expansions • Control soak time to equalise temperatures • Control temperature gradients - NO direct flame impingement! • Control furnace atmosphere to reduce scaling • Control cooling rate to avoid brittle structure formation 4/23/2007 577 of 691
    • Post Weld Heat Treatment Methods Gas furnace heat treatment 4/23/2007 578 of 691
    • Post Weld Heat Treatment Methods HF (Induction) local heat treatment 4/23/2007 579 of 691
    • Post Weld Heat Treatment Methods Local heat treatment using electric heating blankets 4/23/2007 580 of 691
    • Welding Inspector Cutting Processes Section 19 4/23/2007 581 of 691
    • Use of gas flame Welding Heating 4/23/2007 Brazing Straightening Cutting Blasting Gouging Spraying 582 of 691
    • Regulators 583
    • Flashback arrestors Flashback - recession of the flame into or back of the mixing chamber SAFETY SAFETY SAFETY Normal flow Builtin check Flame barrie r valve 4/23/2007 Reverse flow Built-in check valve stops reverse flow Flashback Flashback flame quenched at the flashback barrier 584 of 691
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    • Oxyfuel gas cutting related terms 4/23/2007 587 of 691
    • Oxyfuel gas cutting quality • Good cut - sharp top edge, fine and even drag lines, little oxide and a sharp bottom edge
    • Oxyfuel gas cutting quality • Good cut - sharp top edge, fine and even drag lines, little oxide and a sharp bottom edge 4/23/2007 589 of 691
    • Oxyfuel gas cutting quality • Good cut - sharp top edge, fine and even drag lines, little oxide and a sharp bottom edge 4/23/2007 590 of 691
    • Special oxyfuel operations • Gouging 4/23/2007 593 of 691
    • Special oxyfuel operations • Thin sheet cutting 4/23/2007 594 of 691
    • Cutting Processes Plasma arc cutting • Uses high velocity jet of ionised gas through a constricted nozzle to remove the molten metal • Uses a tungsten electrode and water cooled nozzle • High quality cutting • High intensity and UV radiation 4/23/2007 595 of 691
    • Cutting Processes Air-arc for cutting or gouging 4/23/2007 596 of 691
    • Air-arc gouging features 4/23/2007 597 of 691
    • Welding Inspector Arc Welding Safety Please discuss Section 20 4/23/2007 598 of 691
    • Safety • Electrical safety • Heat & Light • • • • • • – Visible light – UV radiation - effects on skin and eyes Fumes & Explosive Gasses Noise levels Fire Hazards Scaffolding & Staging Slips, trips and falls Protection of others from exposure 4/23/2007 599 of 691
    • Welding Inspector Weldability Of Steels Section 21 4/23/2007 600 of 691
    • Weldability of Steels Definition It relates to the ability of the metal (or alloy) to be welded with mechanical soundness by most of the common welding processes, and the resulting welded joint retain the properties for which it has been designed. is a function of many inter-related factors but these may be summarised as: •Composition of parent material •Joint design and size •Process and technique •Access 4/23/2007 601 of 691
    • Weldability of Steels The weldability of steel is mainly dependant on carbon & other alloying elements content. If a material has limited weldability, we need to take special measures to ensure the maintenance of the properties required Poor weldability normally results in the occurrence of cracking A steel is considered to have poor weldability when: • an acceptable joint can only be made by using very narrow range of welding conditions • great precautions to avoid cracking are essential (e.g., high pre-heat etc) 4/23/2007 602 of 691
    • The Effect of Alloying on Steels Elements may be added to steels to produce the properties required to make it useful for an application. Most elements can have many effects on the properties of steels. Other factors which affect material properties are: •The temperature reached before and during welding •Heat input •The cooling rate after welding and or PWHT 4/23/2007 603 of 691
    • Steel Alloying Elements 4/23/2007 604 of 691
    • Steel Alloying Elements Phosphorus (P): Residual element from steel-making minerals. difficult to reduce below < ~ 0.015% brittleness Sulphur (S): Residual element from steel-making minerals < ~ 0.015% in modern steels < ~ 0.003% in very clean steels Aluminium (Al): De-oxidant and grain size control •typically ~ 0.02 to ~ 0.05% Chromium (Cr): For creep resistance & oxidation (scaling) resistance for elevated temperature service. Widely used in stainless steels for corrosion resistance, increases hardness and strength but reduces ductility. •typically ~ 1 to 9% in low alloy steels 4/23/2007 605 of 691
    • Nickel (Ni)Used in stainless steels, high resistance to corrosion from acids, increases strength and toughness Molybdenum (Mo): Affects hardenability. Steels containing molybdenum are less susceptible to temper brittleness than other alloy steels. Increases the high temperature tensile and creep strengths of steel. typically ~ 0.5 to 1.0% Niobium (Nb): a grain refiner, typically~ 0.05% Vanadium (V): a grain refiner, typically ~ 0.05% Titanium (Ti): a grain refiner, typically ~ 0.05% Copper (Cu): present as a residual, (typically < ~ 0.30%) added to ‘weathering steels’ (~ 0.6%) to give better resistance to atmospheric corrosion 4/23/2007 606 of 691
    • Classification of Steels Mild steel (CE < 0.4) • • Readily weldable, preheat generally not required if low hydrogen processes or electrodes are used Preheat may be required when welding thick section material, high restraint and with higher levels of hydrogen being generated C-Mn, medium carbon, low alloy steels (CE 0.4 to 0.5) • Thin sections can be welded without preheat but thicker sections will require low preheat levels and low hydrogen processes or electrodes should be used Higher carbon and alloyed steels (CE > 0.5) • Preheat, low hydrogen processes or electrodes, post weld heating and slow cooling may be required 4/23/2007 607 of 691
    • Process Cracks • Hydrogen Induced HAZ Cracking (C/Mn steels) • Hydrogen Induced Weld Metal Cracking (HSLA steels). • Solidification or Hot Cracking (All steels) • Lamellar Tearing (All steels) • Re-heat Cracking (All steels, very susceptible Cr/Mo/V steels) • Inter-Crystalline Corrosion or Weld Decay (stainless steels) 4/23/2007 608 of 691
    • Cracking When considering any type of cracking mechanism, three elements must always be present: • • Restraint Restraint may be a local restriction, or through plates being welded to each other • 4/23/2007 Stress Residual stress is always present in a weldment, through unbalanced local expansion and contraction Susceptible microstructure The microstructure may be made susceptible to cracking by the process of welding 609 of 691
    • Cracks Hydrogen Induced Cold Cracking 4/23/2007 610 of 691
    • Hydrogen Induced Cold Cracking May occur: Also know as: • up to 48 hrs after completion Cold Cracking, happens when the welds cool down. • In weld metal, HAZ, parent metal. • At weld toes • Under weld beads • At stress raisers. HAZ cracking, normally occurs in the HAZ. Delayed cracking, as it takes time for the hydrogen to migrate. 48 Hours normally but up to 72, Under-bead cracking, normally happens in the HAZ under a weld bead 4/23/2007 611 of 691
    • Hydrogen Induced Cold Cracking There is a risk of hydrogen cracking when all of the 4 factors occur together: •Hydrogen •Stress More than 15ml/100g of weld metal More than ½ the yield stress •Temperature Below 300oC •Hardness Greater than 400HV Vickers •Susceptible Microstructure (Martensite) 4/23/2007 612 of 691
    • Hydrogen Induced Cold Cracking 4/23/2007 613 of 691
    • Hydrogen Induced Cold Cracking Precautions for controlling hydrogen cracking • Pre heat, removes moisture from the joint preparations, and slows down the cooling rate • Ensure joint preparations are clean and free from contamination • The use of a low hydrogen welding process and correct arc length • Ensure all welding is carried out is carried out under controlled environmental conditions • Ensure good fit-up as to reduced stress • The use of a PWHT • 4/23/2007 Avoid poor weld profiles 614 of 691
    • Hydrogen Induced Cold Cracking 4/23/2007 615 of 691
    • Cellulosic electrodes produce hydrogen as a shielding gas Hydrogen absorbed in a long, or unstable arc Hydrogen introduced in weld from consumable, oils, or paint on plate H2 H2 Martensite forms from γ 4/23/2007 H2 diffuses to γ in HAZ 616 of 691
    • Hydrogen Induced Cold Cracking Susceptible Microstructure: Hard brittle structure – MARTENSITE Promoted by: A) High Carbon Content, Carbon Equivalent (CE) 617 of 691
    • Hydrogen Induced Cold Cracking Typical locations for Cold Cracking 4/23/2007 618 of 691
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    • Hydrogen Scales List of hydrogen scales from BS EN 1011:part 2. Hydrogen content related to 100 grams of weld metal deposited. • Scale A High: >15 ml • Scale B Medium: 10 ml - 15 ml • Scale C Low: 5 ml - 10 ml • Scale D Very low: 3 ml - 5 ml • Scale E Ultra-low: < 3 ml 4/23/2007 621 of 691
    • Potential Hydrogen Level Processes list of welding processes in order of potential lowest hydrogen content with regards to 100g of deposited weld metal. •TIG < 3 ml •MIG < 5 ml •ESW < 5 ml •MMA (Basic Electrodes) < 5 ml •SAW < 10ml •FCAW < 15 ml 4/23/2007 622 of 691
    • Solidification Cracking 4/23/2007 624 of 691
    • Solidification Cracking Also referred as Hot Cracking: Occurring at high temperatures while the weld is hot Centerline cracking: cracks appear down the centre line of the bead. Crater cracking: Small cracks in weld centers are solidification cracks Crack type: Solidification cracking Location: Weld centreline (longitudinal) Steel types: High sulphur & phosphor concentration in steels. Susceptible Microstructure: Columnar grains In direction of solidification 4/23/2007 625 of 691
    • Solidification Cracking • • • • 4/23/2007 626 of 691
    • Solidification Cracking • Sulphur in the parent material may dilute in the weld metal to form iron sulphides (low strength, low melting point compounds) • During weld metal solidification, columnar crystals push still liquid iron sulphides in front to the last place of solidification, weld centerline. • The bonding between the grains which are themselves under great stress and may now be very poor to maintain cohesion and a crack will result, weld centerline. 4/23/2007 627 of 691
    • Solidification Cracking Avoidance
    • Solidification Cracking 4/23/2007 629 of 691
    • Solidification Cracking Precautions for controlling solidification cracking • The use of high manganese and low carbon content fillers • Minimise the amount of stress / restraint acting on the joint during welding • The use of high quality parent materials, low levels of impurities (Phosphor & sulphur) • Clean joint preparations contaminants (oil, grease, paints and any other sulphur containing product) • Joint design selection depth to width ratios 4/23/2007 630 of 691
    • Solidification Cracking Solidification cracking in Austenitic Stainless Steel • particularly prone to solidification cracking • large grain size gives rise to a reduction in grain boundary area with high concentration of impurities • Austenitic structure very intolerant to contaminants (sulphur, phosphorous and other impurities). • High coefficient of thermal expansion /Low coefficient of thermal conductivity, with high resultant residual stress • same precautions against cracking as for plain carbon steels with extra emphasis on thorough cleaning and high dilution controls. 4/23/2007 631 of 691
    • Cracks Lamellar Tearing 4/23/2007 632 of 691
    • Lamellar Tearing Factors for lamellar tearing to occur Cracks only occur in the rolled plate ! Close to or just outside the HAZ ! Cracks lay parallel to the plate surface and the fusion boundary of the weld and has a stepped aspect. • Low quality parent materials, high levels of impurities • Joint design, direction of stress • The amount of stress acting across the joint during welding • Note: very susceptible joints may form lamellar tearing under very low levels of stress 4/23/2007 633 of 691
    • Lamellar Tearing
    • Lamellar Tearing 4/23/2007 635 of 691
    • Lamellar Tearing Susceptible 4/23/2007 Non-Susceptible 636 of 691
    • Lamellar Tearing • • • • • • 4/23/2007 637 of 691
    • Lamellar Tearing Crack type: Lamellar tearing Location: Below weld HAZ Steel types: High sulphur & phosphorous steels Microstructure: Lamination & Segregation 4/23/2007 638 of 691
    • Short Tensile (Through Thickness) Test 4/23/2007 639 of 691
    • Restraint High contractional strains 4/23/2007 Lamellar tear 640 of 691
    • Welding Inspector Practical Visual Inspection Section 22 4/23/2007 641 of 691
    • L S.T.D. 642 of 691
    • HI-LO Single Purpose Welding Gauge 1 2 3 4 5 6 4/23/2007 643 of 691
    • Plate / Pipe Inspection 4/23/2007 644 of 691
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    • Welding Inspector 4/23/2007 650 of 691
    • Welding Temperatures Definitions Preheat temperature • is the temperature of the workpiece in the weld zone immediately before any welding operation (including tack welding!) • normally expressed as a minimum Interpass temperature – is the temperature in a multi-run weld and adjacent parent metal immediately prior to the application of the next run – normally expressed as a maximum Pre heat maintenance temperature = the minimum temperature in the weld zone which shall be maintained if welding is interrupted and shall be monitored during the interruption. 4/23/2007 651 of 691
    • Pre-heat Application Furnace - Heating entire component - best Electrical elements -Controllable; Portable; Site use; Clean; Component cannot be moved. Gas burners - direct flame impingement; Possible local overheating; Less controllable;Portable; Manual operation possible; Component can be moved. Radiant gas heaters - capable of automatic control; No flame impingement; No contact with component; Portable. Induction heating - controllable; Rapid heating (mins not hours); Large power supply; Expensive equipment 4/23/2007 652 of 691
    • Measuring pre heat in Welding Parameters to be measured:
    • Pre-heat Application Application Of Preheat • Heat either side of joint • Measure temp 2 mins after heat removal • Always best to heat complete component rather than local if possible to avoid distortion • Preheat always higher for fillet than butt welds due to different combined thicknesses and chill effect factors. 4/23/2007 654 of 691
    • Pre-Heat Application Manual Gas Operation 655 of 691
    • Welding Temperatures 4/23/2007 656 of 691
    • Welding Temperatures 4/23/2007 657 of 691
    • Combined Thickness The Chilling Effect of the Joint 4/23/2007 658 of 691
    • Combined Thickness 4/23/2007 659 of 691
    • Combined Thickness Combined chilling effect of joint type and thickness. 4/23/2007 660 of 691
    • The Chill Effect of the Material 4/23/2007 661 of 691
    • Heating Temperature Control • TEMPILSTICKS - crayons, melt at set temps. Will not measure max temp. • Pyrometers - contact or remote, measure actual temp. • Thermocouples - contact or attached, very accurate, measure actual temp. 4/23/2007 662 of 691
    • Temperature Test Equipment 4/23/2007 663 of 691
    • Temperature Test Equipment 4/23/2007 664 of 691
    • Temperature Test Equipment 4/23/2007 665 of 691
    • Temperature Test Equipment 4/23/2007 666 of 691
    • Temperature test equipment 4/23/2007 667 of 691
    • Welding Inspector Calibration Section 24 4/23/2007 668 of 691
    • Calibration, validation and monitoring Definitions: 4/23/2007
    • Calibration and validation Frequency - When it is required? 4/23/2007 670 of 691
    • Welding parameter calibration/validation Which parameters need calibration/validation? 4/23/2007 671 of 691
    • PAMS (Portable Arc Monitor System) 4/23/2007 672 of 691
    • PAMS (Portable Arc Monitor System) 4/23/2007 673 of 691
    • Use of PAMS 4/23/2007 674 of 691
    • Use of PAMS 4/23/2007 675 of 691
    • Summary • a welding power source can only be calibrated if it has meters fitted • the inspector should check for calibration stickers, dates etc. • a welding power source without meters can only be validated that the control knobs provide repeatability • the main role is to carryout “in process monitoring” to ensure that the welding requirements are met during production 4/23/2007 676 of 691
    • Welding Inspector Macro/Micro Examination Section 25 4/23/2007 677 of 691
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    • Macro / Micro Examination Object: • Macro / microscopic examinations are used to give a visual evaluation of a cross-section of a welded joint • Carried out on full thickness specimens • The width of the specimen should include HAZ, weld and parent plate • They maybe cut from a stop/start area on a welders approval test 4/23/2007 680 of 691
    • Macro / Micro Examination Will Reveal: • Weld soundness • Distribution of inclusions • Number of weld passes • Metallurgical structure of weld, fusion zone and HAZ • Location and depth of penetration of weld • Fillet weld leg and throat dimensions 4/23/2007 681 of 691
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    • Metallographic Examination 4/23/2007 683 of 691