Stainless steel pipe welding is an important part of stainless steel pipe processing and has a wide range of applications in many fields. To ensure the quality of the product, the safety of the product can be improved. However, welding defects are extremely unfavorable factors in production. Stainless steel pipe cracks are a common and very dangerous defect. It not only makes the product scrapped, but also may cause major accidents. Therefore, it is necessary to find out the cause of the welding cracks of stainless steel pipes.
Stainless steel contains a variety of metal elements, such as chromium, nickel, carbon, iron, etc. It is because of their existence that it has good ductility and corrosion resistance. However, if the carbon content in the stainless steel pipe is high, the material will be harder. Because 304 stainless steel pipes are harder and not easy to weld, cracking may occur after welding.
If the welding material is used improperly, the steel pipe itself cannot support itself, and creep will occur under high temperature and high load. The embrittlement of the austenitic welded joint and the thermal stress deformation caused by high-temperature condensed water will also cause deformation and cracking of the stainless steel pipe.
The weld of 304 stainless steel pipe is exposed outside, which is also one of the reasons for cracking. In addition, the low tensile strength of 304 stainless steel pipe will also cause cracking. In fact, there are many reasons for the cracking of stainless steel welded pipes, and the corresponding solutions for different cracking reasons are also different. We cannot look at all problems in a unified way, let alone use a unified method to solve them.
The stainless steel pipe cracked. The possible reason is that the stainless steel pipe is too thin. Another reason is that the stainless steel purchased is not 304 or 316, but 201, 202. The nickel content of the model does not meet the standard, that is, the stainless steel that will rust; if I guess correctly, it should be hydrogen embrittlement. Hydrogen penetrates into the metal structure in the form of atoms, and then combines carbon to cause metal decarburization, and then causes this cracking phenomenon. If you find cracks, replace them quickly. It is very dangerous, especially under high temperature and high pressure. It is more likely to occur.
If you just blindly weld the cracks of 304 stainless steel pipes quickly and ignore the quality of welding, it will also cause welding fractures. These two situations are often encountered when we are working. At this time, we need to remove the pollution of the welding interface and then adjust the welding speed appropriately.
In many cases, when we weld stainless steel pipes, we forget to use environmental protection and combustion-supporting gases, which directly affects the oxidation of the welding parts, and the welding interface is naturally prone to fracture. Therefore, we must carefully keep the combustion-supporting gas and use it reasonably. Only in this way can we effectively avoid cracking and fracture during the welding of 304 stainless steel pipes.
The above is the main content of the causes of stainless steel pipe welding cracks. There must be two conditions for stainless steel pipe welding cracks, namely stress and corrosive media, and chloride ion concentration and temperature are important factors causing corrosion. And it can be analyzed through a microscope that dendritic cracks are stress corrosion caused by chloride ions.
