Maintenance and maintenance of stainless steel caps

　　The stainless steel caps is widely used in pharmaceutical industry, chemical industry, atomic energy, aerospace, machinery and so on. We often encounter in daily life, such as solar energy is used on both sides of the stainless steel caps, for example, the two sides of the tank is also used on the stainless steel caps, visible in our lives, work is ubiquitous. Therefore, maintaining a good stainless steel caps is the absolute principle. Next, Xiaobian introduces you about the maintenance and maintenance of the Sch80 A234 Wpb Stainless Steel Pipe Fitting Cap.

　　The material of the stainless steel caps is divided into carbon steel, alloy and stainless steel. First of all, the maintenance of stainless steel caps is introduced. 06Cr19Ni10 and 304 stainless steel are metastable austenitic stainless steel. When heated in 450-850oC temperature range, the carbon and chromium in the steel combine to precipitate chromium carbide. Because chromium content around chromium carbide is extremely reduced, it forms chromium depleted area and is prone to corrosion. Especially in the two sides of weld bead and hot forming stainless steel caps, this phenomenon is easy to happen.

　　The main stresses produced by pressure vessel in service state are: the stress produced by pressure in vessel; welding residual stress; residual stress produced by forming and processing of stainless steel caps. The superposition of the three stresses makes the tensile stress of the girth weld between the stainless steel caps and the cylinder maximum. Therefore, stress corrosion is easy to occur on both sides of girth weld between stainless steel caps and cylinder. The surface scratches, welding slag, spatter, surface cleaning is not thorough, the use of chloride ion insulation materials such as improper surface protection will cause surface pitting corrosion and stress corrosion.