Defects are a common and almost unavoidable part of every manufacturing process. The welding industry is not an exception to defects, and there are a number of welding defects that take different forms. Welding defects are caused by a number of factors that range from environmental factors to improper technique. You must check the reputation of the welding shop before hiring technicians from that shop. There are three defects in welding that occur commonly, they are discussed extensively below.
Most Common Defects in Welding
- Weld Cracks: Weld cracks are the most common and most serious defects that occur in welding. These cracks typically appear in areas of the metal affected by intense heat or on the surface of the metal. There are three major classifications of weld cracks, each of which is highlighted below.
– Hot Cracks: Hot cracks usually occur during the crystallization process of welding the joints. The temperature in areas that are affected by hot cracks usually rises over 10,000C.
– Cold Cracks: Cold cracks are a very common form of defect in welding. Unlike hot cracks, cold cracks appear when the welding process has been completed. The temperature of the metal is usually cool when a cold crack forms. As such, a cold crack can form a few hours after welding or even a few days in some cases.
– Crater Cracks: Crater cracks are typically shallow cracks. They form when the metal is removed from the weld crater, sooner than the required time.
Remedies for weld cracks include removal of impurities, proper filling of craters, ensuring to use the correct welding speed, usage of proper metal, as well as metal preheat.
- Porosity: Porosity occurs when gas is trapped in the weld pool. The trapped gas could be nitrogen, hydrogen, or even oxygen. Porosity is caused by a number of reasons which include the presence of moisture, contaminated surface, insufficient electrode deoxidant, grease, oil, paint, rust, incorrect surface treatment, excess gas flow, and ineffective gas shielding.
Removing porosity from welds is quite straightforward, you need to clean all materials to be used. Also, ensure to use dry electrodes and maintain the correct distance while welding. You should also identify the gas flow. Also, reduce the arc speed in order to reduce the gases that get trapped in the weld pool. It is not enough to use dry electrodes, you should use electrodes that are of the highest quality.
- Undercut: An undercut is another welding defect that is quite common. This defect is caused by a lot of reasons that include the usage of large electrodes, poor use of shielding glass, incorrect welding speed, poor welding method, and more. This defect is typically caused by poor welding techniques.
The remedy to undercut includes using high-quality electrodes, reducing the arc length of the electrodes while welding, maintaining a proper travel speed, and more.
These major defects of welding which are undercut, porosity, and weld cracks can easily be identified by a professional welding consultants. This is why it is important to hire such professionals before going on with your project.