The document provides information on welding inspection, including the roles and duties of welding inspectors. It discusses inspecting welds prior to, during, and after welding. It also summarizes common weld defects that inspectors examine for, such as cracks, porosity, lack of fusion, and improper weld size or shape. Inspection tools like weld profile gauges and hi-lo gauges are described. Non-destructive testing methods for inspecting welds are also briefly mentioned.
The document discusses various welding defects such as cracks, porosity, undercut, incomplete fusion, incomplete penetration, slag inclusion, and spatter. It describes the causes and remedies for each defect, and also discusses destructive and non-destructive testing methods used to evaluate the quality and strength of welds. Destructive tests involve loading specimens until failure while non-destructive tests like x-rays examine welds without causing damage.
1-Fundamentals of Welding Metallurgy final.pdfssuser263733
This document provides an introduction to welding metallurgy. It discusses various welding processes including fusion welding processes like arc welding, resistance welding, oxyfuel welding and solid state welding processes like friction welding and ultrasonic welding. For fusion welding, it describes the physics behind heat generation and transfer, and explains concepts like the fusion zone, heat affected zone and unaffected base metal zone in a typical weld joint. It provides details on common arc welding techniques involving consumable and non-consumable electrodes. Resistance spot welding and other resistance welding variations are also summarized.
The document provides an overview of welding inspection. It discusses the roles and duties of welding inspectors, including verifying qualifications and documentation, ensuring proper joint preparation and fit-up, monitoring welding processes, and performing post-weld inspections. It also covers common welding defects, inspection of weld size and shape, and examples of problems that can arise from incorrect joint fit-up such as incomplete fusion or burnthrough. The document aims to give insight into basic welding inspection practices and defect prevention.
The document discusses residual stresses and distortion that occur during welding. It explains that residual stresses develop due to local expansion and contraction during welding, and are locked in as elastic strain. Distortion results from the movement caused by these welding stresses. The document outlines various factors that influence residual stress and distortion, such as heat input, restraint, and weld metal volume. It also discusses different types of distortion and several techniques for controlling distortion, such as joint design, offsetting, balanced welding, and clamping.
Welding causes distortion due to differential heating and cooling rates during the process. When heat is applied to part of a structure, it expands locally. If the structure is restrained from expanding uniformly, compressive and tensile stresses develop which can result in distortion. Three factors influence distortion: 1) temperature gradients between regions of the structure, 2) restraint from thermal expansion, and 3) yield strength and modulus of the material at welding temperatures. Distortion can be controlled by techniques such as pre-setting parts, clamping during welding, and post-weld heat treatment.
This document discusses various welding defects such as slag inclusion, undercut, porosity, incomplete fusion, overlap, underfill, spatter, excessive convexity, incomplete penetration, and excessive penetration. It provides the causes and ways to prevent or repair each defect. Nondestructive and destructive testing methods for inspecting welds are also summarized, including visual inspection, ultrasonic testing, radiographic testing, dye penetrant testing, magnetic particle testing, and mechanical tests.
The document discusses various welded joint geometries including butt, corner, T, lap, and edge joints as well as their advantages and disadvantages. It provides examples of different edge shapes and symbols used for each type of joint. Key terms are defined, such as butting member, nonbutting member, and splice member, and load reactions in welded joints are illustrated.
The document discusses welding symbols according to BS 499 part 2. It provides examples of common welding symbols including types of butt welds like single-V and single-U, supplementary symbols like those indicating non-destructive testing and peripheral welds, dimension symbols showing throat thickness and leg length, multiple staggered weld elements, and other symbols like plug welds and seam welds. The document serves as a reference for interpreting welding symbols specified in BS 499 part 2.
The document discusses various welding defects such as cracks, porosity, undercut, incomplete fusion, incomplete penetration, slag inclusion, and spatter. It describes the causes and remedies for each defect, and also discusses destructive and non-destructive testing methods used to evaluate the quality and strength of welds. Destructive tests involve loading specimens until failure while non-destructive tests like x-rays examine welds without causing damage.
1-Fundamentals of Welding Metallurgy final.pdfssuser263733
This document provides an introduction to welding metallurgy. It discusses various welding processes including fusion welding processes like arc welding, resistance welding, oxyfuel welding and solid state welding processes like friction welding and ultrasonic welding. For fusion welding, it describes the physics behind heat generation and transfer, and explains concepts like the fusion zone, heat affected zone and unaffected base metal zone in a typical weld joint. It provides details on common arc welding techniques involving consumable and non-consumable electrodes. Resistance spot welding and other resistance welding variations are also summarized.
The document provides an overview of welding inspection. It discusses the roles and duties of welding inspectors, including verifying qualifications and documentation, ensuring proper joint preparation and fit-up, monitoring welding processes, and performing post-weld inspections. It also covers common welding defects, inspection of weld size and shape, and examples of problems that can arise from incorrect joint fit-up such as incomplete fusion or burnthrough. The document aims to give insight into basic welding inspection practices and defect prevention.
The document discusses residual stresses and distortion that occur during welding. It explains that residual stresses develop due to local expansion and contraction during welding, and are locked in as elastic strain. Distortion results from the movement caused by these welding stresses. The document outlines various factors that influence residual stress and distortion, such as heat input, restraint, and weld metal volume. It also discusses different types of distortion and several techniques for controlling distortion, such as joint design, offsetting, balanced welding, and clamping.
Welding causes distortion due to differential heating and cooling rates during the process. When heat is applied to part of a structure, it expands locally. If the structure is restrained from expanding uniformly, compressive and tensile stresses develop which can result in distortion. Three factors influence distortion: 1) temperature gradients between regions of the structure, 2) restraint from thermal expansion, and 3) yield strength and modulus of the material at welding temperatures. Distortion can be controlled by techniques such as pre-setting parts, clamping during welding, and post-weld heat treatment.
This document discusses various welding defects such as slag inclusion, undercut, porosity, incomplete fusion, overlap, underfill, spatter, excessive convexity, incomplete penetration, and excessive penetration. It provides the causes and ways to prevent or repair each defect. Nondestructive and destructive testing methods for inspecting welds are also summarized, including visual inspection, ultrasonic testing, radiographic testing, dye penetrant testing, magnetic particle testing, and mechanical tests.
The document discusses various welded joint geometries including butt, corner, T, lap, and edge joints as well as their advantages and disadvantages. It provides examples of different edge shapes and symbols used for each type of joint. Key terms are defined, such as butting member, nonbutting member, and splice member, and load reactions in welded joints are illustrated.
The document discusses welding symbols according to BS 499 part 2. It provides examples of common welding symbols including types of butt welds like single-V and single-U, supplementary symbols like those indicating non-destructive testing and peripheral welds, dimension symbols showing throat thickness and leg length, multiple staggered weld elements, and other symbols like plug welds and seam welds. The document serves as a reference for interpreting welding symbols specified in BS 499 part 2.
Welding symbols were developed to provide more information than simply indicating "weld here" on engineering drawings. There are various international standards for welding symbols, including AWS A2.4 in the US and ISO 2553 internationally. While similar, there are differences between standards that can cause confusion. It is important to understand which standard is being referenced when interpreting welding symbols.
This document provides an overview of various joining processes, including fusion welding processes like gas welding, arc welding, TIG welding, MIG welding, plasma arc welding, and electron beam welding. It also discusses solid-state welding processes and resistance welding processes like spot welding and seam welding. Specific details are provided on plasma arc welding and resistance welding, including their principles, advantages, and applications.
This document discusses power presses. It provides classifications of presses based on their mechanism, function, structure, and controllability. The main types are mechanical, hydraulic, and pneumatic presses. It also describes the construction and working of gap frame presses, including their components like the flywheel, clutch, brakes, and ram. Cutting operations performed by presses include blanking, piercing, notching, and perforating. Forming operations change the contour through bending and drawing. Safety measures for presses include bi-manual controls and light sensors.
Welding Defects
Eurotech Now inteducing Welding Defects. Welding Defect is any type of flaw in the object which requires welding. Seven type of Welding Defect
Seven type of Common weld defects include:
1. Lack of fusion
2. Lack of penetration or excess penetration
3. Porosity
4. Inclusions
5. Cracking
6. Undercut
7. Lamellar tearing
Any of these defects are potentially disastrous as they can all give rise to high stress intensities which may result in sudden unexpected failure below the design load or in the case of cyclic loading, failure after fewer load cycles than predicted.
Welding is a process that joins two metal pieces by heating them to melting point and allowing them to fuse together. The main welding processes are electric arc, gas, thermit, resistance, and friction welding. Proper surface preparation and use of fluxes is important to remove impurities and oxides. Different types of fluxes are used depending on the metal and process. Arc welding uses an electric arc to generate heat and melt the metals. It requires a welding power source, cables, electrode holder, ground clamp, and protective gear. Various arc welding techniques exist including manual, inert gas shielding, and submerged arc welding. Weld quality depends on current, speed, position and type of joint.
This document discusses various types of weld discontinuities and defects including misalignment, undercut, insufficient fill, excessive reinforcement, overlap, burn-through, incomplete penetration, incomplete fusion, arc strikes, and inclusions such as slag, wagontracks, and tungsten. Each discontinuity or defect is defined, potential causes are identified, methods for prevention are provided, and repair techniques are described. The document serves as a reference for identifying and addressing common weld problems and defects.
Residual stresses are stresses that exist in a material after external loads have been removed. They are caused by non-uniform temperatures during welding which lead to uneven strain. Residual stresses form from mismatches in thermal expansion and contraction between the weld metal and base metal. Higher heat input welds and greater restraint during welding generally result in higher residual stresses, with tensile stresses in the weld metal and compressive stresses farther away. Residual stresses can decrease strength and increase susceptibility to cracking if not properly addressed.
1. Welding is a metal joining process that involves applying heat, pressure, or both to joining materials. There are several types of welding processes including solid state welding, fusion welding, and pressure welding.
2. Solid state welding joins metals below their melting point using mechanical pressure and heat. Examples are cold welding, ultrasonic welding, friction welding, and friction stir welding.
3. Resistance welding generates heat for welding through electrical resistance across components. Common resistance welding methods are spot welding, seam welding, and projection welding.
This document discusses the selection process for different types of welding electrodes. It describes consumable electrodes that are classified based on their flux coatings to suit different arc characteristics, welding positions, and quality requirements. The key types of flux coatings include cellulosic, rutile, iron oxide, and basic low-hydrogen coatings. Important constituents in flux coatings like TiO2, CaCO3, and CaF2 are outlined. Guidelines for selecting electrode size based on current and coating factor are also provided. Classification systems for coated electrodes and guidelines for selecting between pure, thoriated, and zirconiated tungsten electrodes are summarized.
Artech Welders Private Limited took roots in 1994 with the dream of manufacturing Capacitor Discharge (CD) projection welding machines. Powered by a vision to blend power saving with aesthetics, Artech has today germinated into a force to reckon with in the field of resistance welding. A wide range of end users embrace the quality welding that Artech offers. They include manufacturers of automobile sheet metal components, stainless steel impellers, sheet metal products, diamond tools like cup wheels and core drills, hollow metal doors, auto electricals, control panels, stainless steel cookware and kitchenware to name a few.
The document discusses various types of casting defects including their forms, causes, and prevention methods. It covers shaping faults from pouring like misruns and cold shuts caused by low metal temperature or moisture in sand. Shrinkage defects from inadequate gating and risering are described. Contraction defects like hot tears occur when thin and thick sections cool at different rates. Gas defects result from entrapped gases or gases evolving during solidification. Inclusions and sand defects enter the melt during pouring. Dimensional errors occur from mold distortions. Compositional errors and segregation vary the alloy composition.
Basic knowledge of Gas Tungsten Arc Welding (GTAW) for freshers in the field. This is one of the welding process that produces one of the highest quality of weld for high integrity structures...
The document provides terminology and definitions related to welding inspection of steels. It discusses the duties of a welding inspector, relevant codes and standards, the welding procedure, destructive and non-destructive testing methods, defects, consumables, and welding processes. Key terms defined include types of welds (butt, fillet, edge), types of joints (butt, tee, corner, lap), features of welds (toe, face, root, throat), and sizes of different welds (full penetration butt welds, partial penetration butt welds, fillet welds).
This document summarizes several solid-state welding processes including cold welding, ultrasonic welding, friction welding, resistance welding, and flash welding. It provides brief descriptions of each process along with examples of applications and diagrams illustrating how each process works. The key solid-state welding processes covered are friction welding, resistance spot welding, and friction stir welding.
Gas Metal Arc Welding or MIG welding .
Gas metal arc welding (GMAW), sometimes referred to by its subtypes metal inert gas (MIG) welding or metal active gas (MAG) welding, is a welding process in which an electric arc forms between a consumable wire electrode and the workpiece metal(s), which heats the workpiece metal(s), causing them to melt and join
pulsed spray
globular spray
This document discusses welding defects and welding processes. It describes various types of welding including arc welding, gas welding, resistance welding, thermit welding, solid state welding, and newer welding techniques. It then discusses common welding defects such as slag inclusion, undercut, porosity, incomplete fusion, overlap, underfill, spatter, excessive convexity/concavity, excessive weld reinforcement, incomplete penetration, and excessive penetration. For each defect it provides the potential causes and recommendations for prevention and repair.
The document discusses various types of discontinuities and defects that can occur in welding, including cracks, porosity, inclusions, insufficient penetration, and more. It defines discontinuities as interruptions in material structure that are not necessarily defects, while defects render a part unable to meet standards. Causes, preventions, and potential repairs are provided for each issue. Engineering problems can arise from design mistakes, while weld process issues relate to techniques and metallurgy.
Welding is a process used to join metal materials by heating them to the point of melting and allowing them to fuse together and harden. There are several types of welding including electric arc welding, gas welding, resistance welding, friction welding, and robotic welding. The document provides details on the key techniques such as MIG, TIG, oxy-acetylene gas welding and resistance spot welding. It also summarizes the equipment, processes, advantages and applications of each welding method.
This document discusses various causes of weld failure and how to prevent them. It identifies several types of weld failures including overload, hot cracking, hydrogen induced cracking, and metallurgical failures. It also discusses defects such as cracks, lack of fusion, and porosity. To minimize failures, the document recommends carefully designing welds based on loading conditions, ensuring accessibility for welding, controlling distortion, considering the welding environment, matching processes to materials, and including safety factors in weld design stresses.
Welds can fail due to several causes: overload, poor joint design, or bad welding methods. Proper joint design is important to ensure good fusion and avoid defects from rapid heat dissipation. Welding procedures must be qualified to produce acceptable quality welds, and welders must pass approval tests to demonstrate their skills match the approved procedures. Supervision by qualified personnel is also important when carrying out welding operations.
Welding symbols were developed to provide more information than simply indicating "weld here" on engineering drawings. There are various international standards for welding symbols, including AWS A2.4 in the US and ISO 2553 internationally. While similar, there are differences between standards that can cause confusion. It is important to understand which standard is being referenced when interpreting welding symbols.
This document provides an overview of various joining processes, including fusion welding processes like gas welding, arc welding, TIG welding, MIG welding, plasma arc welding, and electron beam welding. It also discusses solid-state welding processes and resistance welding processes like spot welding and seam welding. Specific details are provided on plasma arc welding and resistance welding, including their principles, advantages, and applications.
This document discusses power presses. It provides classifications of presses based on their mechanism, function, structure, and controllability. The main types are mechanical, hydraulic, and pneumatic presses. It also describes the construction and working of gap frame presses, including their components like the flywheel, clutch, brakes, and ram. Cutting operations performed by presses include blanking, piercing, notching, and perforating. Forming operations change the contour through bending and drawing. Safety measures for presses include bi-manual controls and light sensors.
Welding Defects
Eurotech Now inteducing Welding Defects. Welding Defect is any type of flaw in the object which requires welding. Seven type of Welding Defect
Seven type of Common weld defects include:
1. Lack of fusion
2. Lack of penetration or excess penetration
3. Porosity
4. Inclusions
5. Cracking
6. Undercut
7. Lamellar tearing
Any of these defects are potentially disastrous as they can all give rise to high stress intensities which may result in sudden unexpected failure below the design load or in the case of cyclic loading, failure after fewer load cycles than predicted.
Welding is a process that joins two metal pieces by heating them to melting point and allowing them to fuse together. The main welding processes are electric arc, gas, thermit, resistance, and friction welding. Proper surface preparation and use of fluxes is important to remove impurities and oxides. Different types of fluxes are used depending on the metal and process. Arc welding uses an electric arc to generate heat and melt the metals. It requires a welding power source, cables, electrode holder, ground clamp, and protective gear. Various arc welding techniques exist including manual, inert gas shielding, and submerged arc welding. Weld quality depends on current, speed, position and type of joint.
This document discusses various types of weld discontinuities and defects including misalignment, undercut, insufficient fill, excessive reinforcement, overlap, burn-through, incomplete penetration, incomplete fusion, arc strikes, and inclusions such as slag, wagontracks, and tungsten. Each discontinuity or defect is defined, potential causes are identified, methods for prevention are provided, and repair techniques are described. The document serves as a reference for identifying and addressing common weld problems and defects.
Residual stresses are stresses that exist in a material after external loads have been removed. They are caused by non-uniform temperatures during welding which lead to uneven strain. Residual stresses form from mismatches in thermal expansion and contraction between the weld metal and base metal. Higher heat input welds and greater restraint during welding generally result in higher residual stresses, with tensile stresses in the weld metal and compressive stresses farther away. Residual stresses can decrease strength and increase susceptibility to cracking if not properly addressed.
1. Welding is a metal joining process that involves applying heat, pressure, or both to joining materials. There are several types of welding processes including solid state welding, fusion welding, and pressure welding.
2. Solid state welding joins metals below their melting point using mechanical pressure and heat. Examples are cold welding, ultrasonic welding, friction welding, and friction stir welding.
3. Resistance welding generates heat for welding through electrical resistance across components. Common resistance welding methods are spot welding, seam welding, and projection welding.
This document discusses the selection process for different types of welding electrodes. It describes consumable electrodes that are classified based on their flux coatings to suit different arc characteristics, welding positions, and quality requirements. The key types of flux coatings include cellulosic, rutile, iron oxide, and basic low-hydrogen coatings. Important constituents in flux coatings like TiO2, CaCO3, and CaF2 are outlined. Guidelines for selecting electrode size based on current and coating factor are also provided. Classification systems for coated electrodes and guidelines for selecting between pure, thoriated, and zirconiated tungsten electrodes are summarized.
Artech Welders Private Limited took roots in 1994 with the dream of manufacturing Capacitor Discharge (CD) projection welding machines. Powered by a vision to blend power saving with aesthetics, Artech has today germinated into a force to reckon with in the field of resistance welding. A wide range of end users embrace the quality welding that Artech offers. They include manufacturers of automobile sheet metal components, stainless steel impellers, sheet metal products, diamond tools like cup wheels and core drills, hollow metal doors, auto electricals, control panels, stainless steel cookware and kitchenware to name a few.
The document discusses various types of casting defects including their forms, causes, and prevention methods. It covers shaping faults from pouring like misruns and cold shuts caused by low metal temperature or moisture in sand. Shrinkage defects from inadequate gating and risering are described. Contraction defects like hot tears occur when thin and thick sections cool at different rates. Gas defects result from entrapped gases or gases evolving during solidification. Inclusions and sand defects enter the melt during pouring. Dimensional errors occur from mold distortions. Compositional errors and segregation vary the alloy composition.
Basic knowledge of Gas Tungsten Arc Welding (GTAW) for freshers in the field. This is one of the welding process that produces one of the highest quality of weld for high integrity structures...
The document provides terminology and definitions related to welding inspection of steels. It discusses the duties of a welding inspector, relevant codes and standards, the welding procedure, destructive and non-destructive testing methods, defects, consumables, and welding processes. Key terms defined include types of welds (butt, fillet, edge), types of joints (butt, tee, corner, lap), features of welds (toe, face, root, throat), and sizes of different welds (full penetration butt welds, partial penetration butt welds, fillet welds).
This document summarizes several solid-state welding processes including cold welding, ultrasonic welding, friction welding, resistance welding, and flash welding. It provides brief descriptions of each process along with examples of applications and diagrams illustrating how each process works. The key solid-state welding processes covered are friction welding, resistance spot welding, and friction stir welding.
Gas Metal Arc Welding or MIG welding .
Gas metal arc welding (GMAW), sometimes referred to by its subtypes metal inert gas (MIG) welding or metal active gas (MAG) welding, is a welding process in which an electric arc forms between a consumable wire electrode and the workpiece metal(s), which heats the workpiece metal(s), causing them to melt and join
pulsed spray
globular spray
This document discusses welding defects and welding processes. It describes various types of welding including arc welding, gas welding, resistance welding, thermit welding, solid state welding, and newer welding techniques. It then discusses common welding defects such as slag inclusion, undercut, porosity, incomplete fusion, overlap, underfill, spatter, excessive convexity/concavity, excessive weld reinforcement, incomplete penetration, and excessive penetration. For each defect it provides the potential causes and recommendations for prevention and repair.
The document discusses various types of discontinuities and defects that can occur in welding, including cracks, porosity, inclusions, insufficient penetration, and more. It defines discontinuities as interruptions in material structure that are not necessarily defects, while defects render a part unable to meet standards. Causes, preventions, and potential repairs are provided for each issue. Engineering problems can arise from design mistakes, while weld process issues relate to techniques and metallurgy.
Welding is a process used to join metal materials by heating them to the point of melting and allowing them to fuse together and harden. There are several types of welding including electric arc welding, gas welding, resistance welding, friction welding, and robotic welding. The document provides details on the key techniques such as MIG, TIG, oxy-acetylene gas welding and resistance spot welding. It also summarizes the equipment, processes, advantages and applications of each welding method.
This document discusses various causes of weld failure and how to prevent them. It identifies several types of weld failures including overload, hot cracking, hydrogen induced cracking, and metallurgical failures. It also discusses defects such as cracks, lack of fusion, and porosity. To minimize failures, the document recommends carefully designing welds based on loading conditions, ensuring accessibility for welding, controlling distortion, considering the welding environment, matching processes to materials, and including safety factors in weld design stresses.
Welds can fail due to several causes: overload, poor joint design, or bad welding methods. Proper joint design is important to ensure good fusion and avoid defects from rapid heat dissipation. Welding procedures must be qualified to produce acceptable quality welds, and welders must pass approval tests to demonstrate their skills match the approved procedures. Supervision by qualified personnel is also important when carrying out welding operations.
The document discusses common weld defects that can occur in thermal power plants, including porosity, slag inclusions, excess penetration, incomplete fusion, undercut, inadequate joint penetration, cracking, and welding debris. It describes the causes and effects of each defect and measures to prevent their occurrence in order to ensure weld quality and structural integrity.
Visual inspection is an important quality control technique for welding. It can identify surface flaws and imperfections before, during, and after welding. Prior to welding, inspectors should check materials, fit-up, and other factors. During welding, inspectors monitor the process. After welding, inspectors check for discontinuities like cracks, incomplete fusion or penetration, undercut, and porosity. They also ensure the weld meets size and dimensional requirements. Fillet weld size can be measured using a fillet weld gage, which measures the leg length or throat of the weld.
This document discusses various types of discontinuities that can occur in welds and base metals. It defines discontinuities as irregularities that interrupt an otherwise uniform structure, and defines defects as discontinuities that impair suitability for intended use. Various discontinuities are described such as cracks, incomplete fusion, porosity, undercut, and laminations. Cracks are generally the most detrimental as they can propagate under stress. The shape, location, and causes of different discontinuities are explained to help identify and evaluate their severity. The document provides detailed information on discontinuities to aid in non-destructive testing and quality control of welds.
There are numerous welding processes including arc welding, electron beam welding,
friction welding, laser welding, and resistance welding. This article will concentrate on arc
welding, which is the most common technique used to join most steels. Factors affecting
weld quality will be discussed and how to avoid common weld defects will be presented.
Arc welding requires striking a low-voltage, high-current arc between an electrode and the
base metal. The intense heat generated with this arc melts the base metal and allows the
joining of two components. The characteristic of the metal that is being welded and the joint
type (i.e. groove, fillet, etc.) dictates the welding parameters and the procedure that needs to
be followed to obtain a sound weld joint.
The document provides information on various welding processes and factors related to welding design and quality. It discusses different welding techniques, their typical applications based on production quantities, joint design considerations for minimizing distortion and stresses, non-destructive and destructive testing methods, and common welding defects such as lack of fusion, undercut, porosity, overlap and their causes.
This document discusses different types of weld cracking that can occur, including centerline cracking and heat affected zone cracking. Centerline cracking occurs in the center of a weld bead and can be caused by segregation of low melting point constituents, bead shape, or surface profile. Heat affected zone cracking occurs in the base material next to the weld and is caused by the presence of hydrogen, a susceptible material microstructure, and residual stress. Both types of cracking must be prevented by controlling variables like welding parameters, joint design, filler material selection, and cleaning surfaces to remove moisture.
This document discusses different types of weld cracking that can occur, including centerline cracking and heat affected zone cracking. Centerline cracking occurs in the center of a weld bead and can be caused by segregation of low melting point constituents, bead shape, or surface profile. Heat affected zone cracking occurs in the base material next to the weld and is caused by the presence of hydrogen, a susceptible material microstructure, and residual stress. Both types of cracking must be prevented by controlling welding parameters such as joint design, welding process, filler material selection, and eliminating sources of hydrogen.
This document discusses common welding defects, their causes, and possible remedies. It details various geometric imperfections like misalignment caused by improper setup or plates of different thickness. Other defects mentioned include undercutting from incorrect welding techniques, porosity from contamination or inadequate shielding, incomplete fusion from insufficient penetration, and cracking caused by cooling or restraint issues. The document emphasizes the importance of defect detection and correction to ensure welds can safely perform their intended purpose.
The document discusses various welding defects including lamellar tearing, porosity, underfill, insufficient
penetration, wagon tracks, arc strikes, and incomplete fusion. Lamellar tearing occurs beneath welds in rolled steel
plate and is caused by transverse strain from welding, a weld orientation parallel to inclusions, and poor material
ductility. Porosity is caused by absorbed gases like nitrogen, oxygen, and hydrogen which become trapped during
solidification. Prevention methods for defects include using proper joint design, welding techniques, materials, and
preheating when necessary. Defects require removal and rewelding to repair.
This document discusses various types of cracking that can occur in welds, including centerline cracking, heat affected zone cracking, and transverse cracking. It describes the causes and conditions required for each type of cracking, such as solidification processes, residual stresses, and hydrogen embrittlement. Prevention methods are also covered, like preheating materials, controlling hydrogen levels, and using filler metals designed to prevent cracking. The document provides detailed information on characterizing weld microstructures and properties to evaluate cracking tendencies.
A concise presentation about underwater welding. It briefly discusses about the main types, risks involved and practices involved in underwater welding
Underwater welding is a specialized welding process that involves welding at depths below the surface of water. It can be classified as wet welding, where welding is done directly in water, or dry welding, where a dry chamber is created to perform the welding. Wet welding uses manual metal arc welding with direct current power and special electrodes. It allows for work in difficult to reach areas but results in lower quality welds due to quenching from the water. Dry welding produces higher quality welds by working in a pressurized chamber, but requires more complex and expensive equipment. Underwater welding is used for offshore construction, ship repair, and pipeline maintenance.
Welding is a process that joins materials by causing fusion and filling the joint with a filler material. There are several advantages to welding including lighter structures, maximum strength in joints, easy alterations, pleasing appearance, and strength equal to the parent material. Spot welding uses two electrodes to locally fuse materials and is commonly used in automotive and aircraft industries to join sheet metal. MIG welding uses an inert gas shield to prevent contamination and is often used for carbon/alloy steels, stainless steel, aluminum and other metals due to its high welding speed and economy. Common welding defects include lack of penetration, undercut, slag inclusion, porosity, cracks, spatter, and distortion.
Cracks can form in welds due to stresses exceeding the metal's strength. There are two main types of cracks: hot cracks during solidification and cold cracks caused by hydrogen embrittlement. Factors like composition, thickness, restraint and hydrogen content influence cracking. Cracks are classified by location as weld metal cracks like longitudinal or transverse cracks, or base metal cracks like underbead cracks. Tests evaluate cracking susceptibility and techniques like preheating, heat input control and post heating can reduce cracking risks.
This Presentation covers the basic concepts of Hot cracks and cold cracks in welding. For more information, please refer the books mentioned in the references slide.... Thank you
Welded connections in steel structures - Limit State Design of Steel StructuresAshishVivekSukh
Two members are connected by means of welds is known as welded connection.
More efficient use of the materials.
Earlier designers considered welds as less fatigue resistant.
Good welds achive at site is impossible.
Testing and quality control of welds became easier because NDT
This document discusses various types of welding defects and imperfections including lack of fusion, porosity, slag inclusions, and solidification cracking. It describes how to identify each type, their causes, best practices for prevention, acceptance standards, and methods for detection and remediation. The key types of imperfections are classified as fabrication defects occurring during welding or service defects that form during use, and guidelines are provided for minimizing defects and producing quality welds.
The document discusses revisions made to the ANSI/AWWA D102 Standard for coating steel water storage tanks. Examples of revisions include adopting performance requirements for new interior and exterior coating systems, and adding pre-construction primers and two new coating systems. The purpose of the standard is to provide minimum requirements for materials, coating systems, surface preparation, application, and inspection of tank coatings. Extended service life estimates are provided for various coating systems.
This document provides details of the design of a headed concrete anchor and end plate connection supporting a reinforced concrete beam. Key details include:
- Supported member is a hopper applying 5000kg vertical force
- Anchor bolt diameter is 20mm
- There are 4 anchors in a 2x2 configuration spaced 50mm apart
- Concrete strength is 40MPa
- Checks are performed to ensure the connection has sufficient capacity for the applied tension and shear loads considering factors like concrete breakout strength, steel strength, pryout strength, etc. with all checks indicating the design is safe.
This document provides an overview of aviation turbine fuel, including:
1) It discusses the early history of jet propulsion and the development of turbine engines in the 1930s-1940s. Kerosine was initially used to fuel early turbine engines.
2) After WWII, the U.S. Air Force began using "wide-cut" fuel but later transitioned to kerosine-type fuel (JP-8) in the 1970s for better performance. Commercial aviation also uses kerosine-type fuels like Jet A and Jet A-1.
3) Jet fuel consumption in the U.S. has more than doubled over the past 25 years, growing from 32 million gallons per day in 1974
Avery hardoll whittaker controls 4 inch self sealing ind couplingsVaradaraj Ck
The document summarizes self-sealing industrial couplings designed to connect and disconnect hoses and pipelines under pressure without spillage. The couplings are primarily used in petroleum, chemical and brewing industries. They connect using a straightforward turning motion that engages the units, locks and seals them together, and opens internal valves to allow flow with minimal pressure drop. Disconnection causes the valves to fully close before the units separate, resulting in negligible spillage.
Ip model code of safe practice part 19 2nd ed. jan. 2007 part1Varadaraj Ck
The document notifies the customer that there is an editorial change needed to Model code of safe practice Part 19: Fire precautions at petroleum refineries and bulk storage installations (2nd edition). Specifically, section 4.8.3 paragraph 5 should include the word 'operational' so that it states the bund should be capable of holding 110% of the maximum operational capacity of the tank. Customers are asked to update their copy with this correction.
Ul 142 steel above ground tanks for flammable and combustible liquidsVaradaraj Ck
The document discusses the benefits of meditation for reducing stress and anxiety. Regular meditation practice can help calm the mind and body by lowering heart rate and blood pressure. Studies have shown that meditating for just 10-20 minutes per day can have significant positive impacts on both mental and physical health over time.
Embedded machine learning-based road conditions and driving behavior monitoringIJECEIAES
Car accident rates have increased in recent years, resulting in losses in human lives, properties, and other financial costs. An embedded machine learning-based system is developed to address this critical issue. The system can monitor road conditions, detect driving patterns, and identify aggressive driving behaviors. The system is based on neural networks trained on a comprehensive dataset of driving events, driving styles, and road conditions. The system effectively detects potential risks and helps mitigate the frequency and impact of accidents. The primary goal is to ensure the safety of drivers and vehicles. Collecting data involved gathering information on three key road events: normal street and normal drive, speed bumps, circular yellow speed bumps, and three aggressive driving actions: sudden start, sudden stop, and sudden entry. The gathered data is processed and analyzed using a machine learning system designed for limited power and memory devices. The developed system resulted in 91.9% accuracy, 93.6% precision, and 92% recall. The achieved inference time on an Arduino Nano 33 BLE Sense with a 32-bit CPU running at 64 MHz is 34 ms and requires 2.6 kB peak RAM and 139.9 kB program flash memory, making it suitable for resource-constrained embedded systems.
Harnessing WebAssembly for Real-time Stateless Streaming PipelinesChristina Lin
Traditionally, dealing with real-time data pipelines has involved significant overhead, even for straightforward tasks like data transformation or masking. However, in this talk, we’ll venture into the dynamic realm of WebAssembly (WASM) and discover how it can revolutionize the creation of stateless streaming pipelines within a Kafka (Redpanda) broker. These pipelines are adept at managing low-latency, high-data-volume scenarios.
Introduction- e - waste – definition - sources of e-waste– hazardous substances in e-waste - effects of e-waste on environment and human health- need for e-waste management– e-waste handling rules - waste minimization techniques for managing e-waste – recycling of e-waste - disposal treatment methods of e- waste – mechanism of extraction of precious metal from leaching solution-global Scenario of E-waste – E-waste in India- case studies.
DEEP LEARNING FOR SMART GRID INTRUSION DETECTION: A HYBRID CNN-LSTM-BASED MODELgerogepatton
As digital technology becomes more deeply embedded in power systems, protecting the communication
networks of Smart Grids (SG) has emerged as a critical concern. Distributed Network Protocol 3 (DNP3)
represents a multi-tiered application layer protocol extensively utilized in Supervisory Control and Data
Acquisition (SCADA)-based smart grids to facilitate real-time data gathering and control functionalities.
Robust Intrusion Detection Systems (IDS) are necessary for early threat detection and mitigation because
of the interconnection of these networks, which makes them vulnerable to a variety of cyberattacks. To
solve this issue, this paper develops a hybrid Deep Learning (DL) model specifically designed for intrusion
detection in smart grids. The proposed approach is a combination of the Convolutional Neural Network
(CNN) and the Long-Short-Term Memory algorithms (LSTM). We employed a recent intrusion detection
dataset (DNP3), which focuses on unauthorized commands and Denial of Service (DoS) cyberattacks, to
train and test our model. The results of our experiments show that our CNN-LSTM method is much better
at finding smart grid intrusions than other deep learning algorithms used for classification. In addition,
our proposed approach improves accuracy, precision, recall, and F1 score, achieving a high detection
accuracy rate of 99.50%.
International Conference on NLP, Artificial Intelligence, Machine Learning an...gerogepatton
International Conference on NLP, Artificial Intelligence, Machine Learning and Applications (NLAIM 2024) offers a premier global platform for exchanging insights and findings in the theory, methodology, and applications of NLP, Artificial Intelligence, Machine Learning, and their applications. The conference seeks substantial contributions across all key domains of NLP, Artificial Intelligence, Machine Learning, and their practical applications, aiming to foster both theoretical advancements and real-world implementations. With a focus on facilitating collaboration between researchers and practitioners from academia and industry, the conference serves as a nexus for sharing the latest developments in the field.
6th International Conference on Machine Learning & Applications (CMLA 2024)ClaraZara1
6th International Conference on Machine Learning & Applications (CMLA 2024) will provide an excellent international forum for sharing knowledge and results in theory, methodology and applications of on Machine Learning & Applications.
ACEP Magazine edition 4th launched on 05.06.2024Rahul
This document provides information about the third edition of the magazine "Sthapatya" published by the Association of Civil Engineers (Practicing) Aurangabad. It includes messages from current and past presidents of ACEP, memories and photos from past ACEP events, information on life time achievement awards given by ACEP, and a technical article on concrete maintenance, repairs and strengthening. The document highlights activities of ACEP and provides a technical educational article for members.
Literature Review Basics and Understanding Reference Management.pptxDr Ramhari Poudyal
Three-day training on academic research focuses on analytical tools at United Technical College, supported by the University Grant Commission, Nepal. 24-26 May 2024
Advanced control scheme of doubly fed induction generator for wind turbine us...IJECEIAES
This paper describes a speed control device for generating electrical energy on an electricity network based on the doubly fed induction generator (DFIG) used for wind power conversion systems. At first, a double-fed induction generator model was constructed. A control law is formulated to govern the flow of energy between the stator of a DFIG and the energy network using three types of controllers: proportional integral (PI), sliding mode controller (SMC) and second order sliding mode controller (SOSMC). Their different results in terms of power reference tracking, reaction to unexpected speed fluctuations, sensitivity to perturbations, and resilience against machine parameter alterations are compared. MATLAB/Simulink was used to conduct the simulations for the preceding study. Multiple simulations have shown very satisfying results, and the investigations demonstrate the efficacy and power-enhancing capabilities of the suggested control system.
A SYSTEMATIC RISK ASSESSMENT APPROACH FOR SECURING THE SMART IRRIGATION SYSTEMSIJNSA Journal
The smart irrigation system represents an innovative approach to optimize water usage in agricultural and landscaping practices. The integration of cutting-edge technologies, including sensors, actuators, and data analysis, empowers this system to provide accurate monitoring and control of irrigation processes by leveraging real-time environmental conditions. The main objective of a smart irrigation system is to optimize water efficiency, minimize expenses, and foster the adoption of sustainable water management methods. This paper conducts a systematic risk assessment by exploring the key components/assets and their functionalities in the smart irrigation system. The crucial role of sensors in gathering data on soil moisture, weather patterns, and plant well-being is emphasized in this system. These sensors enable intelligent decision-making in irrigation scheduling and water distribution, leading to enhanced water efficiency and sustainable water management practices. Actuators enable automated control of irrigation devices, ensuring precise and targeted water delivery to plants. Additionally, the paper addresses the potential threat and vulnerabilities associated with smart irrigation systems. It discusses limitations of the system, such as power constraints and computational capabilities, and calculates the potential security risks. The paper suggests possible risk treatment methods for effective secure system operation. In conclusion, the paper emphasizes the significant benefits of implementing smart irrigation systems, including improved water conservation, increased crop yield, and reduced environmental impact. Additionally, based on the security analysis conducted, the paper recommends the implementation of countermeasures and security approaches to address vulnerabilities and ensure the integrity and reliability of the system. By incorporating these measures, smart irrigation technology can revolutionize water management practices in agriculture, promoting sustainability, resource efficiency, and safeguarding against potential security threats.
2. WELDING PRESENTATION
BY
RANDALL STREMMEL
The Certified Welding Inspector (CWI) plays an important role during any welded
construction activities ensuring the required specifications and standards are
followed. Due to the numerous materials and processes associated with metal
joining (welding) THIS PRESENTATION SHALL SHOW ONLY THE
BASIC WELDING PROCESSES AND EXAMINATION METHODS
(NDE). National and International Codes and Specifications along with measuring
devices are the Inspector’s tools. Hopefully the following presentation shall give an
insight into basic welding inspection.
4. WELD FAILURES
Today welding is the most common method used for joining steel
fabrications largely because of the speed at which joints can be made
and the reliability of these joints in service. However because most
welding operations are now relatively simple to perform it is all too
easy to forget the complexity of the chemical and metallurgical actions
that are taking place when the weld is being deposited. Therefore not
surprisingly welds occasionally fail.
5. OVERLOAD
Before applying the various design formulas, the problem itself must
be analyzed and clearly stated. This is not always obvious, and trying
to solve the wrong problem can quickly lead to insufficient design
stresses. When a load is placed on a member, stress and strain
result. Stress is the internal resistance to the applied force. Strain is
the amount of "give or deformation caused by the stress, such as
deflection in bending, elongation in tension, contraction in
compression, and angular twist in torsion.
6. OVERLOAD
For example of this is a lifting lug on a pressure vessel. If the vessel is lifted by
a spreader beam the loading condition on the lug consists of a simple vertical
force putting the attachment welds either in tension or shear. However if the
vessel is lifted with a rope sling the loading condition becomes more complex
because there is now a horizontal component of the force to consider as well
a the vertical one, which effectively increases the loading on the welds.
9. HOT CRACKING
This type of cracking occurs when the weld is starting to solidify,
in the pasty state, as it posses very little strength and therefore
any residual loading is likely to cause it to break before it has fully
solidified. The problem can be compounded by impurities that are
forced out of the solidifying weld, becoming trapped in the center
of the weld during final solidification. Hot cracking can occur
where their is a high degree of restraint in the structure of the
fabrication or where the structure moves slightly as the weld
solidifies.
10. HOT CRACKING
A good example of this type of failure is on the weld used to secure the small
plug in the mandrill hole of a spun dished head on a pressure vessel, a weld that
many people do not take seriously because of its size. As the weld cools it
contracts causing the plug to move , if the weld at the other side of the plug is
still solidifying it could easily fail. This is because of the very high contraction
stresses generated by the plug as the weld starts to solidify.
12. BAD WELDING METHODS
It is very important when carrying out any welding to ensure that it is
done correctly. Consideration has to be given to all aspects of the
process and also the environment. Often welding has to be carried
out under site conditions, the welding is often carried out in situation
so that small general purpose electrodes are used resulting in low
weld heat input which when combined with no preheat gives very
rapid heat dissipation. Which can create a hard micro structure
particularly in the location of the heat affected zone.
13. BAD WELDING METHODS
This along with high levels of residual stress will create the ideal condition for hydrogen induced cracking, which although normally associated with high strength steels
can occur in low carbon steels if the conditions are right. The resulting crack may not occur immediately the weld cools down but some time afterward, therefore if
this type of failure is expected non destructive examination should be delayed by at least 48 hours after welding.
15. METALLURGICAL FAILURE
Materials that are to be welded have to tolerate severe thermal
transients created by the welding process without suffering
deterioration of their mechanical properties or adverse phase
changes. The metallurgical composition or temper conditions of
certain types of metal may make them unsuitable to weld or may
require special controls to be imposed during the welding operation.
For example some steels that are easy to machine may contain high
levels of sulphur that may result in cracking of any attaching weld.
Therefore this type of material should not be used on load bearing
fabricated items such as the eye bolts that are often found holding
down man way covers on pressure vessels.
16. WELD DEFECTS
They can usually be attributed to the welders inability to set up and
manipulate the welding equipment; although bad joint design and
faulty welding equipment can also be responsible. The most
significant defects are cracks and those that resemble cracks such as
lack of fusion, cold overlap etc. This is because of the risk that the
crack may become unstable and propagate when loaded causing a
dramatic failure often by brittle fracture
17. WELD DEFECTS
Porosity seldom causes weld failure in multi-run welds however it
is a sign that something has gone wrong with welding operation
and can often be caused by other defects that may not have been
detected such as lack of side wall fusion. Weld profile can also
cause failure, if the weld size is too small because the joint is
underfilled with weld then its load carrying capability will be
reduced, if the joint contains excessive weld metal this can create a
notch effect which can lead to failure by fatigue if the loading
condition fluctuates.
18. WELD DEFECTS
Bad fit up excessive root penetration on single sided welds can
create defects in the root of the weld such as wormholes and
even cracking. Distortion of welded joints can cause failure by
buckling if the welded member is subjected to compressive loads.
22. DUTIES PRIOR TO WELDING
Obtain all relevant documentation…
Relevant specifications.
Relevant procedures.
Copies of welders test test certificates.
Copies of drawings.
23. DUTIES PRIOR TO WELDING
Obtain all relevant documentation…
Ensure welder qualification.
Correct material type condition etc.
Correct equipment with certificates.
Correct consumables type condition, size.
Correct pre heat.
24. DUTIES PRIOR TO WELDING
Assess / measure fit up…
Root face.
Bevel angle.
Root gap.
Alignment.
Joint cleanliness.
Ensure no undue stress is applied to the joint.
27. DUTIES AFTER WELDING
Ensure welds are post cleaned.
Visual inspection of welds for defects.
Visually check for arc strikes.
Check weld contour and weld width.
Ensure joint is covered to retard cooling rate.
Ensure monitor post weld heat treatment.
45. SHAPE (BUTT WELDS)
Ideally, (a) is the most desirable but
very often it may be difficult to achieve.
Because of this, one should assess
the excess weld height in conjunction
with the weld profile and perhaps the
toe blending.
Consider:
46. SHAPE (FILLET WELDS)
In normal practice, (a) is the most desirable
but, again, in many instances it is difficult to
achieve. Acceptance levels, therefore, allow
tolerances on weld shape.
Consider:
47. TOE BLEND (BUTT WELDS)
For butt welds, consider:
In normal practice, (a) is the most
desirable but, again, in many instances
it is difficult to achieve. Acceptance
levels, therefore, allow tolerances on
weld shape.
Depending on the service conditions
of the product, the toe blend may be
of greater importance than the size
and shape of the weld. A poor toe
blend may reduce service life by a
considerable margin if the product is
under a cyclic load.
48. TOE BLEND (FILLET WELDS)
For fillet welds,
consider:
In normal practice, (a) is the most
desirable but, again, in many
instances it is difficult to achieve.
Acceptance levels, therefore,
allow tolerances on weld shape.
49. ROOT DEFECTS
Incomplete root penetration
Failure of weld metal to extend into the root of a joint
Lack of root fusion
Lack of union at the root of a joint
Excess penetration bead
Excess weld metal protruding through the root of
a fusion weld made from one side only
50. ROOT DEFECTS
Root concavity
(suck-back; underwashing - non-standard terms)
A shallow groove which may occur in the root of a
butt weld, but full fusion is evident
Shrinkage groove
A shallow groove caused by contraction in the metal
along each side of a penetration bead or along the
weld centerline
Burn through
(melt through)
A localized collapse of the molten pool due to
excessive penetration, resulting in a hole in the weld
run
51. CONTOUR DEFECTS
Incompletely filled groove
A continuous or intermittent channel in
the surface of a weld, running along its
length, due to insufficient weld metal.
The channel may be along the centre
or along one or both edges of the weld
53. UNEQUAL LEGS
Unequal legs
(non standard term)
Variation of leg length on a fillet weld
Note: Unequal leg lengths may be
specified as part of the design - in which
case they are not imperfections
54. UNDERCUT
Undercut
An irregular groove at a toe of a run in the
parent metal or in previously deposited
weld metal
The inspector must determine if the
undercut is continuous or intermittent, or
sharp or smooth
55. OVERLAP
Overlap
An imperfection at the toe or root of a weld
caused by metal flowing on to the surface of
the parent metal without fusing to it
56. GAS PORE
Gas pore
A cavity, generally under 1.5mm in
diameter, formed by trapped gas
during the solidification of molten
metal
Porosity
A group of gas pores
57. CRATER PIPE
Crater pipe
A depression due to shrinkage at the end of a
run where the source of heat was removed.
Crater pipes may also lead to micro-cracking
58. SURFACE CRACKS
Crack
A linear discontinuity produced by fracture
Cracks may be ...
a) Longitudinal, in the weld metal, i.e. centreline
b) Longitudinal, in the parent metal or heat affected zone
c) Transverse
d) Crater crack (star cracking)
59. ARC STRIKE
Stray flash/arc burn/arc strike
(stray arcing)
1. The damage on the parent material
resulting from the accidental striking of an
arc away from the weld
2. The accidental striking of an arc away
from the weld
Note that the same term is used for both
the action and the result
60. WELD WIDTH
For butt welds and fillet welds,
consider:
Weld width and consistency of weld
width
87. VISUAL INSPECTION
Visual inspection is the one NDT method used extensively to
evaluate the condition or the quality of a weld or component. It is
easily carried out, inexpensive and Visual inspection is the one NDT
method used extensively to evaluate the condition or the quality of
a weld or component. It is easily carried out, inexpensive and
usually doesn't require special equipment.
88. RADIOGRAPHY
X-rays are produced by high voltage x ray
machines whereas gamma rays are
produced from radioactive isotopes such
as Iridium 192 The x-ray or gamma rays
are placed close to the material to bc
inspected and they pass through the
material and are then captured on film
This film is then processed and the image
is obtained as a series of gray shades
between black and white.
89. MAGNETIC PARTICLE INSPECTION
Magnetic particle inspection is a method that can
be used to find surface and near surface flaws in
ferromagnetic materials such as steel and iron.
The technique uses the principle that magnetic
lines of force {flux) will be distorted by the
presence of a flaw in a manner that will reveal it's
presence. the flaw (for example, a crack) is
located from the "flux leakage", following the
application of fine iron particles, to the area under
examination. There are variations in the way the
magnetic field is applied. but they are all
dependant on the above principle .
90. PENETRANT TESTING INSPECTION
Liquid penetration inspection is a method that is used to
reveal surface breaking flaws by bleed out of a colored or
fluorescent dye from the flaw.
91. ULTRASONIC TESTING
Ultrasonic inspection uses sound waves of short
wavelength and high frequency to detect flaws or
measure material thickness. It is used on aircraft, the
power stations generating plant, or welds in pressure
vessels at an oil refinery or paper mill.