Abstract

Abstract:
Welding is an indispensable manufacturing process used and its effectiveness may be measured by its ability to produce joints of acceptable quality at the lowest possible cost. Unacceptable joint quality may arise from a failure to comply with the specified design or from the incidence of weld defects. These problems are, however, preventable if their causes are understood and the correct operating procedures are followed.
The most common welding problems include:
• Spatter, molten weld metal ejected from the weld.
• Cracking, there are different mechanisms which can lead to the problem, such as solidification cracking, HAZ liquation cracking, reheat cracking and cold cracking.
• Porosity, holes formed in the weld metal from entrapped gases.
• Shape defects, such as overfill, root convexity, root concavity, undercut, lack of penetration and lack of fusion.
• Distortion, the buckling and bending of the component due to stress applied by the heating and cooling of the material.