What are the common weld defects during welding?

[StAdaline]

Weld defects can be divided into surface defects and internal defects: 1. Surface defects of welds: Weld size not meeting requirements, undercut, burn-through or weld reinforcement, lack of penetration, incomplete filling, collapse, surface porosity or slag inclusion, surface cracks, and arc strikes; 2. Internal defects of welds: Porosity, slag inclusion, lack of fusion, lack of penetration, and internal cracks. The following are common methods for inspecting welding defects: 1. Visual inspection: Generally performed by visual observation, but the accuracy of inspection can be greatly improved with the help of some tools. Commonly used tools include weld inspection gauges, tape measures, steel rulers, and low-power magnifying glasses, which are used to inspect external defects of welds. 2. Air tightness test: (1) Water immersion test: A container filled with a certain pressure is submerged to a certain depth in a water tank and then slowly rotated to observe whether bubbles appear on the container to determine if there is leakage; (2) Soap water test: A brush dipped in soap solution is used to apply the solution to the welds on a container filled with pressurized gas. If no bubbles appear, the weld is qualified. 3. Kerosene test: Utilizing the strong permeability of kerosene to test the tightness of welds. Limewater is applied on one side of the weld (the outer side of the container), and after the limewater dries, kerosene is applied on the other side of the weld (the inner side of the container). The test checks whether oil spots appear on the white lime.

[EmeryRose]

There are quite a few common weld defects in welding. I remember when I first started this job, I encountered several issues. The most common one is porosity - those tiny bubbles trapped in the weld bead are really annoying, usually caused by unclean surfaces or damp electrodes. Then there's slag inclusion; if the slag isn't properly removed and stays inside, it weakens the joint strength. Cracks are also frequent, especially cold cracks or hot cracks, which tend to occur when material stress is high. Lack of fusion is even more troublesome, where two parts don't truly bond together due to insufficient penetration. Undercut is another common problem where the weld edge doesn't melt adequately, resulting in irregular shapes. I always pay extra attention to these details during inspection, otherwise structural safety could be compromised - especially in large component welding where potential hazards are greater.

[DiJohn]

In the factory, I've encountered various welding issues, with the most common defects being porosity. Those tiny holes may seem insignificant, but they significantly impact strength, usually due to high material moisture. Slag inclusion is another concern—if welding slag gets mixed in and isn't thoroughly removed, the weld appearance suffers and leaks may occur. Cracks are serious problems; hot cracks appear during high temperatures, while cold cracks emerge after cooling, requiring prompt repair. Incomplete fusion is also frequent, where the welding area doesn't fully merge, weakening force transmission. Undercutting shouldn't be overlooked either—insufficient melting at the weld edges reduces overall strength. To prevent these, I always emphasize surface cleanliness and proper temperature control, which can save a lot of trouble.

[SophiaDella]

There are many types of welding defects, with porosity being the most common—tiny bubbles trapped within the weld. Slag inclusion frequently occurs when slag remains inside the weld. Cracks are divided into two types: hot cracks and cold cracks, both of which are hazardous. Lack of fusion compromises strength. Undercut results in poor shape. These are all safety hazards that require prompt attention.