The welding process is a very successful way to fabricate two metal pieces, but there are some key points that a welder should remember to avoid any weld defects that can lead to welding failure or hazards. Common welding defects can lead to cracks or inclusion, but there are many other factors that have the potential to cause failures. The prime aim of the article is to identify and prevent the potential failures which can lead to any catastrophe. Let’s look into some factors:
Ignoring the welding process- Neglecting to follow the proper weld process contributes to the weld failure. The welder should remember to properly utilize preheat and control the inter-pass temperature. Interpassing temperature slows down the rate of cooling in the base material and the weld deposit. It ultimately helps to reduce the risk of hydrogen induced cracking while welding carbon and low alloy steels. The welder should start the welding process by referring to the filler metal product data sheet for welding parameters recommendations. Every filler metal has a different nature and not one size fits all.
Stress Risers- It is caused by poor weld design or inadequate welding techniques which can lead to tearing, breaking, or cracking. There are certain types of stress risers such as Undercut, Porosity, Hot cracking, Cold cracking & Inclusions. If the welder follows some steps like cleaning the base metal, removal of moisture, preheating & inter-pass the temperature control and increasing the wire diameter can prevent weld failure.
Poor part or welding design: Insufficient weld designs like design error or wrong interpretation of the part design can lead to welding failure. This happens due to the inability of an undersized weld to support the intended load in a static structure, where the welded design can fail due to compression, tension, bending, or torsional loads. To avoid these kinds of scenarios the welder should look into the chemistry of it, to gain proper fusion and desired weld.
Incorrect Testing: Welders always need to use code-approved testing standards for new procedure development, focusing on the correct number and type of testing for mechanical and chemical properties and/or non-destructive testing. How strict or critical the application is factored into how stringent testing should be. The code will specify acceptance criteria for production-made welds using either penetrant testing (PT) or DP ( Die Penetration) Test , magnetic particle testing (MP), radiographic testing (RT), and/or ultrasonic testing (UT).
By following the above mentioned pointers a welder can avoid the welding failures.