1. The welding seam reinforcement is too high: when the angle of the welding groove is too small or the welding current is too small, this phenomenon will occur. Because stress concentration is prone to damage, in order to improve the fatigue life of the pressure vessel, it is required to level the reinforced height of the weld.
 

2. Welding flash: The molten metal flows to the unmelted welding elbow on the edge of the molten pool, and accumulates to form a welding flash, which is not fused with the welding elbow. Weld flash has no effect on static load strength, but will cause stress concentration and reduce dynamic load strength

 3. Burn through: Burn through means that part of the molten metal leaks from the reverse side of the weld, or even burns through into a hole, which reduces the strength of the joint.

 4. The weld is too concave: the strength of the joint is reduced due to the reduction of the working section of the weld.

 

5. Weld undercut: The depression formed along the edge of the weld on the welding elbow is called undercut, which not only reduces the working section of the joint, but also causes serious stress concentration at the undercut.

 

The above five defects exist on the surface of the weld, which can be found with the naked eye and can be repaired in time. If the operation is skilled, it can generally be avoided.

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