Sensitization treatment is performed on 304 stainless steel strip. The so-called sensitization treatment generally refers to austenitic stainless steel that has been solution treated. After heating at 500~850 degrees, chromium is precipitated from the solid solution to form chromium carbide, causing austenitic stainless steel. The grain boundary corrosion susceptibility of bulk stainless steel, which is sensitization treatment, is used to measure the grain boundary corrosion tendency of austenitic stainless steel, which is one of the detection methods. The following is a detailed introduction.
Photosensitive treatment does not actually belong to the heat treatment method that should be used in the production and manufacture of 303 stainless steel bars or their products. The method is a detection method for detecting the intergranular corrosion resistance of 304 stainless steel strips. Photosensitive treatment is essentially a treatment method that makes austenitic stainless steel more sensitive to intergranular corrosion. Due to the sensitization treatment, austenitic stainless steel (FeCr) 23C6 and other alloy carbides can be precipitated along the grain boundary in large quantities, causing intergranular corrosion in the intergranular corrosion medium, so as to achieve rapid detection of austenitic stainless steel. Intergranular corrosion resistance .
The domestic test method for intergranular corrosion resistance of 304 stainless steel generally stipulates that the sensitization treatment system of austenitic stainless steel containing C ≤ 0.03% or containing stable elements is: heating to 650 ° C, forging and rolling material test pieces are insulated for 2h Air-cooled, and the casting material test piece was insulated for 2h and air-cooled.
In some special occasions, in order to more strictly evaluate the intergranular corrosion resistance of the material, in some standards, the sensitization system of 316 stainless steel bars is more strictly specified, according to the temperature used in the workpiece and the content of the material in the future. Factors such as carbon content and whether it contains aluminum elements, etc., use different sensitization systems. Others control the lifting speed of the sensitization process. Therefore, when judging the intergranular corrosion tendency of 304 stainless steel strip, attention should be paid to the sensitization system.