P22 elbow

P22 elbow is a general term for a variety of alloy elbows. It is used to connect two pipes with the same nominal diameter at pipe bends to make the pipe turn at 90 ° or other angles. Its materials are various, and P22 elbow is widely used

Common problems of P22 elbow

● Lack of penetration: lack of penetration refers to a defect of partial lack of fusion between welded alloy elbow and weld metal or weld layer. Incomplete penetration weakens the working section of the weld, reduces the strength of the joint, and causes serious stress concentration, which often becomes the source of weld cracking

● Slag inclusion: non-metallic slag is mixed in the weld, which is called slag inclusion. Slag inclusion reduces the working section of the weld, causes stress concentration, and reduces the strength and impact toughness of the weld

● Porosity: when the weld metal is at high temperature, it is too late to discharge when the molten pool is cooled and solidified, but holes are formed inside or on the surface of the weld, that is, porosity, which absorbs too much gas (such as H2) or gas (such as CO) generated by metallurgical reaction in the molten pool. The existence of porosity reduces the working section of the weld and reduces the mechanical strength of the joint. If there are penetrating or continuous pores, the sealing of the weldment will be seriously affected

● Cracks: during or after welding, they may also occur in the heat affected zone on both sides of the weld. Local metal cracks in the welding joint area are called cracks. Cracks may occur on the weld, sometimes on the metal surface, and sometimes inside the metal