1803 stainless steel is not 30 1. 1803 used to be called 304D, but it was actually made of 20 1, and the quality was 20 1. Neither the stainless steel door factory nor the master can use it. Because the materials are mixed, in order to save cost, the content of nickel is reduced, but the content of manganese, copper and nitrogen is increased, but the corrosion resistance has not been verified for a long time; The service life will be reduced, but the hardness will become brittle, so the master of stainless steel deep processing will generally not use it. So 1803 stainless steel is not 30 1.