The requirements of stainless steel welded pipe welding technology are directly related to the quality of stainless steel welded pipe. The welding of 316L stainless steel welded pipe is good or bad. The mouth of the pipe is very important. Today we will talk about the importance of the groove before welding of stainless steel pipe.
The selection principle of the groove form is to ensure the quality of the welded joint, to ensure the welding head and to avoid welding defects and welding deformation as much as possible, to minimize the consumption of welding materials, and to ensure the operability of the process.
There are many welding methods for stainless steel: arc welding, electronic speed welding, laser welding, electric resistance welding, and arc welding including submerged arc welding, tungsten gas shielded welding, gas metal arc welding, and plasma welding.
Welding materials: The welding materials should be selected according to the principle of “equal composition”. At the same time, in order to enhance the resistance of joints to thermal cracking and intergranular corrosion and reduce the content of ferrite, we generally choose HoeCr19Ni12Mo2 welding wire for argon arc welding, and The CHSO22 electrode is used as a supplementary material.
Welding parameters: This kind of stainless steel is sensitive to heat, so it should be welded with a small current. The welding speed should be fast. When performing multi-layer welding, the interlayer temperature should be controlled. Generally, the interlayer temperature should be less than 60 °C.
Groove form: The general groove is a V-shaped groove, the blunt edge of the groove is about 0-0.5mm, and the groove angle is 65°-70°.
Welding technical requirements for 316L stainless steel welded pipe
(1) When using manual arc welding, the welding should be reversed by DC. If it is argon arc welding, it should be DC positive.
(2) Before the welding wire is used, the welding rod should be dried as required to prevent the generation of pores. The 20mm surface of both the groove and the weldment to be welded shall be cleaned. There shall be no oil, paint, scale and other impurities. If necessary, clean it with alcohol or acetone, or even polish it. Otherwise, the weld metal will produce pores. And carbon increase.
(4) The thickness of the weld should be uniform and uniform when the bottom welding is performed, and the root should be well fused. When the arc is closed, a gentle slope should be formed. When the arc is extinguished, the crater should be filled to prevent the crater from cracking.
(5) The welding should be carried out in sections, and after cooling, it can be cooled by water, which can increase the cooling speed of the joint and reduce the welding stress, which can be said to be two.