The so-called sensitizing treatment generally refers to austenitic stainless steel that has been solid-solution treated. After being heated at 500 to 850 degrees, chromium is precipitated from the solid solution to form chromium carbide, causing austenite. The grain boundary corrosion sensitivity of 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.

Photosensitive processing is actually not a heat treatment method that should be used in the production and manufacture of 303 stainless steel bars or their products. This method is a detection method for detecting the resistance of stainless steel strip to intergranular corrosion. Photosensitive processing is essentially a processing method that makes austenitic stainless steel more sensitive to intergranular corrosion. Because the sensitization treatment can make austenitic stainless steel (FeCr) 23C6 and other alloy carbides precipitate along the grain boundary in a large amount, it will produce intergranular corrosion in the intergranular corrosion medium, so as to achieve rapid detection of the resistance of austenitic stainless steel to intergranular corrosion.

The domestic testing method for corrosion resistance of stainless steel strip generally stipulates that the sensitization treatment system of austenitic stainless steel containing C≤0.03% or containing stable elements is: heating to 650℃, heat insulation for forging and rolling specimens, air cooling for 2 hours, the cast material test piece is insulated for 2h and air-cooled.

In some special occasions, in order to more strictly evaluate the resistance to intergranular corrosion of materials, in some standards, the sensitization system of 316 stainless steel bars is more stringent. Different sensitization systems are adopted for factors such as the amount of carbon and whether it contains aluminum. Others control the lifting speed of the sensitization treatment. Therefore, when judging the tendency of intergranular corrosion of stainless steel strips, attention should be paid to the sensitization system.