Stainless steel throat hoop is a kind of stainless steel with ferrite structure in service. The content of chromium is in the range of 11% ~ 30%, and it has body centered cubic crystal structure. This kind of steel generally does not contain nickel, and sometimes contains a small amount of Mo, Ti, Nb and other elements. This kind of steel has the characteristics of high thermal conductivity, small expansion coefficient, good oxidation resistance, excellent stress corrosion resistance, etc., and is mostly used to make parts resistant to atmospheric, steam, water and oxidizing acid corrosion. This kind of steel has some disadvantages, such as poor plasticity, low plasticity and corrosion resistance after welding, which limits its application. The application of out of furnace refining technology (AOD or VOD) can greatly reduce carbon, nitrogen and other interstitial elements, so this kind of steel is widely used

How to avoid the damage of stainless steel hoop in the process of use and manufacture

Stainless acid resistant steel is called stainless steel for short. It is composed of stainless steel and acid resistant steel. In short, the steel that can resist atmospheric corrosion is called stainless steel, and the steel that can resist chemical medium corrosion is called acid resistant steel. Generally speaking, the steel with more than 12% Cr has the characteristics of stainless steel. According to the microstructure after heat treatment, stainless steel can be divided into five categories: ferritic stainless steel, martensitic stainless steel, austenitic stainless steel, austenitic ferritic stainless steel and precipitation carbonization

During the manufacturing process of stainless steel throat hoop equipment, there will be performance damage, defects and some substances that affect the surface, such as dust, floating iron powder or embedded iron, heat recovery color and other oxide layer, rust spot, grinding burr, welding arc spot, welding spatter, flux, welding defect, oil and grease, residual adhesive and paint, chalk and marking pen, etc. Most of them are ignored because of their harmful effects. However, they are potentially harmful to the oxidation protection film. Once the protective film is damaged, thinned or changed by other methods, the underlying stainless steel will begin to corrode. Corrosion generally does not spread over the entire surface, but at or around the defect. This kind of local total corrosion is usually pitting corrosion or crevice corrosion. These two kinds of corrosion will develop to depth and breadth, and most of the surface is not eroded. Grinding and machining will cause surface roughness, leaving grooves, overlap and burr and other defects.