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  2. 2. ContentsTerms & DefinitionTypes of WeldsTypes of JointsWeld PreparationsTypes of Single Butt PreparationButt Welded JointFillet Weld ProfileEffect of a Poor Toe Blend AngleSummary of TermsDuties of Welding InspectorResponsibilities of Welding InspectorImperfections in Welded JointsMechanical TestingMacro Inspection
  3. 3. A Weld:* A union between materials caused by heat, and or pressureA Joint:* A configuration of members Text Page Ref 1:1
  4. 4. Butt welds:*Fillet welds:*Spot/Seam welds:*Plug/Slot welds:*Edge welds:*
  5. 5. Butt joints: *T joints: *Lap joints: *Corner joints:* Closed Open corner corner*
  6. 6. Angle of bevel*Root face* Included angle* Root radius* Root gap* Root landing*
  7. 7. Single bevelSingle VSingle JSingle U*
  8. 8. Double bevelDouble VDouble JDouble U*
  9. 9. A butt welded butt joint*A fillet welded butt joint*A compound welded butt joint*
  10. 10. A fillet welded T joint*A butt welded T joint*A compound welded T joint*
  11. 11. A fillet welded Lap joint*A spot welded Lap joint*A compound welded Lap joint*
  12. 12. A fillet welded Closed Corner joint*A butt welded Closed Corner joint*A compound welded Closed Corner joint*
  13. 13. An inside fillet welded Open Corner joint* CAn outside fillet welded Open Corner joint*A double fillet welded Open Corner joint*
  14. 14. Weld Face*Actual Throat Thickness* Weld Width* Weld Toes* Design Throat Thickness* 1 2 A B 3 4 HAZ* Weld Root* A + B = Excess Weld Metal**
  15. 15. Vertical Leg Length* Weld face*Horizontal Leg Length* Excess weld metal ** Design throat* Actual throat*
  16. 16. 6 mm 80°Very Poor Weld Toe Blend Angle 3 mm* 20°Improved Weld Toe Blend Angle
  17. 17. 90° 3 mmExtremely poor toe blend, but excess weld metal is within limits*
  18. 18. Weld: A Union of materialsJoint: A Configuration of membersWeld Preparation: Preparing a joint to allow access and fusion.Types of Weld: Butt. Fillet. Spot. Seam Plug. Slot. Edge.Types of Joint: Butt. T. Lap. Corner (Open & Closed)Types of Preparation: Bevel’s. V’s. J’s. U’s. Single & Double Sided.Preparation Terms: Bevel/included angle. Root face/gap. Land/RadiusWeldment Terms: Weld face & root. HAZ. Weld toes.Weld widthWeld Sizing (Butts): DTT. ATT. Excess weld metal.Weld Sizing (Fillets): DTT. ATT. Excess weld metal. Leg length *
  19. 19. It is the duty of all welding inspectors:To ensure that welding operations are carried out inaccordance with written, or agreed practices orspecifications Before * During After
  20. 20. Discuss the following Before Welding:1) Safety: Rules.2) Documentation: Spec. Drawings. Procedures. Welder approvals. Certificates. Mill sheets3) Welding Process and accessories: Equipment,Cables, Regulators, Ovens etc4) Incoming Consumables: Materials/welding consumables (Size. Condition. Specification. Storage)5) Marking out preparation & set up: Method. Angles/Root face/gap values. Distortion control. Pre-heat prior to tack welding if applicable*
  21. 21. During Welding:1) Pre-Heating (Min 15 C as per UW-30 ASME Section VIII Div-I)2) In process distortion control (Balance or sequence welding)3) Consumable control. (Correct baking for E-7018 260-425 C and storage 30-140 C prior to use)4) Welding process (Related parameters i.e. volts/amps. gas flow rate)5) Welding run sequence and inter-pass cleaning6) Minimum/maximum Inter-pass temperatures (150 C for SS, 250 C for CS.7) Full compliance with all elements given on the WPS*
  22. 22. After Welding:1) Visual Inspection2) Non Destructive testing3) Repairs*4) Repair procedures (NDT/Welding/Welder approval)5) PWHT6) Hydro-static testing7) Submission of all inspection reports to QC departments*
  23. 23. To Observe Activities & Imperfections*To Record Activities & Imperfections* Activities &To Compare Imperfections*
  24. 24. A Welding Inspectors toolbox should contain*A welding gauge (Cambridge style, or high low gauges etc)A tape measure and scaleA wire brushA magnifying glassA torch and mirrorA specification, pen and report, or note paper
  25. 25. Welding imperfections can be categorized into groups: 1) Cracks 2) Gas Pores & Porosity 3) Solid Inclusions 4) Lack of fusion 5) Profile & Lack of Filling 6) Mechanical or Surface damage 7) Misalignment*
  26. 26. A HAZ hydrogen crack, initiated at the weld toeMost cracks are initiated from stress concentrations *
  27. 27. Surface breaking porosity Shrinkage cavity* Coarse cluster porosityFine cluster porosity Blow hole > 1.6 mm Ø Hollow root bead An isolated internal porosity
  28. 28. Surface breaking solid inclusionInternal solid inclusion causinga lack of inter-run fusion* Internal solid inclusion causing a lack of sidewall fusion Internal solid inclusion Solid inclusions caused by undercut in the previous weld run
  29. 29. Lack of sidewall fusion & incompletely filled grove* Overlap (Causing cold laps)Lack of inter-run fusion Lack of sidewall fusion Lack of root fusion
  30. 30. Spatter An Incompletely filled groove A Lack of root fusion Bulbous, or irregular contour Arc Strikes Poor toe blend BIncomplete root penetration *
  31. 31. Root Run or “Hot pass” undercut Parent metal, surface undercut Weld metal, surface undercut*
  32. 32. Weld metal, surface undercut Parent metal, “top toe” undercut*
  33. 33. Any surface damage caused by:GrindingHammering/chisel marksSlag chipping hammer marksArc strikes
  34. 34. Linear Excess weld metal height Lowest plate to highest point 3 mm Linear misalignment measured in mm (over 13mm to 19mm as per UW 33 of ASME Sec VIII Div-I) Angular 15°Angular misalignment measured in degrees*
  35. 35. Why ?* To establish the level of mechanical properties* propertiesWhich properties ?* 1) Hardness* 2) Toughness (Impact Test)* 3) Tensile strength* 4) Ductility*
  36. 36. We test welds to establish minimum levels of mechanicalproperties, and soundness of the welded joint*We divide tests into Quantitative & Qualitative methods:* 1) Quantitative tests: 1) Quantitative tests: (Have units)* (Have units)* 2) Qualitative tests: 2) Qualitative tests: (Have no units)* (Have no units)*
  37. 37. Types of tests include: 1) Quantitative tests: 1) Quantitative tests: Hardness tests Hardness tests Toughness tests Toughness tests Tensile strength tests* Tensile strength tests* 2) Qualitative tests: 2) Qualitative tests: Macro tests Macro tests Bend tests Bend tests Fracture tests* Fracture tests*
  38. 38. The specimen below has been polished and is ready to be hardness tested = Hardness SurveyThickness Base metal HAZ Fusion boundary Weld metal
  39. 39. Generally we use a diamond or steel ball to form an indentationWe measure the width of the indentation to gauge the hardness*
  40. 40. 1) Vickers Diamond Pyramid: Always uses a diamond*2) Brinell hardness test: Always uses a steel ball*3) Rockwell hardness test: Uses a ball, or diamond depending on the scale*
  41. 41. Machined notch 10 x 10 mmThe specimen may be tested from different areas of the weld.*Graduated scale Pendulum Hammerof absorbedenergy in Joules* Location of specimen
  42. 42. 1) Charpy V test: 10 x 10 (Specimen horizontal) Joules*2) Izod test: 10 x 10 (Specimen vertical) Ft.lbs*
  43. 43. Radius (For radius reduced test specimens only) Weld Test gripping area HAZDirection of test Plate material Reduced Section Used to assess the tensile strength of the weld metal
  44. 44. All Weld Metal Tensile TestingDirection of the test * Tensile test piece cut along weld specimen.
  45. 45. Firstly, before the tensile test 2 marks are made 50mm 50 mmDuring the test, Yield point & Tensile strength are measuredThe specimen is put together and the marks are re-measured 75 mmA new measurement of 75mm will indicate Elongation E50 %*
  46. 46. 1) Excess Weld Metal Height 7) Poor Toe Blend* 6)Porosity2) Lack of Sidewall Fusion 5) Root Penetration3) Lack of Root Fusion4) Slag inclusion & Lack of inter-run fusion
  47. 47. Bend tests are used to establish fusion in the area under testGuide A Guided root bend test* Lack of root fusion shown here* FormerTest Piece ForceFurther tests include face, side and longitudinal bend tests*For material over 12 mm thickness, side bend test may beused*
  48. 48. Specimen prior to test* Specimen after test*
  49. 49. The main difference between Macro & Micro is that Micro isthe study of the micro-structure at much higher magnificationThe limit of Macro inspection is magnification < X 10The specimen is usually cut from a stop/start in the test piece
  50. 50. Remember! The process of inspection is to first:Observe, then Report, then Compare!*