Several identification methods of stainless steel（一）

Physical identification is to determine whether it is stainless steel with the help of simple instruments and the senses according to the inherent physical and chemical properties of the product (including the whole material, residual material, waste, etc.) when the steel grade (number) is unknown. And the specific method of which type of stainless steel.

It should be pointed out that sensory identification cannot distinguish the specific steel (type) number, but can only basically distinguish three major categories of chromium stainless steel, chromium nickel stainless steel and chromium manganese nitrogen stainless steel. The identification methods are as follows:

Identification of color ：The pickled stainless steel has a silvery white and smooth surface color: chromium-nickel stainless steel is silvery white and jade; chromium stainless steel is slightly grayish and weak; the color of chromium-manganese-nitrogen stainless steel is similar to that of chromium-nickel stainless steel. The surface color of unpickled stainless steel: chrome-nickel steel is brown-white, chrome steel is brown-black, and chromium-manganese-nitrogen is black (these three colors refer to the more heavily oxidized colors). Cold-rolled unannealed chromium-nickel stainless steel, with silver-white reflective surface.

Identifying with iron magnets： Magnets can basically distinguish two types of stainless steel. Because chromium stainless steel can be attracted by magnets in any state; chromium-nickel stainless steel is generally non-magnetic in the annealed state, and some will be magnetic after cold working. However, high manganese steel with higher manganese content is non-magnetic; the magnetic situation of chromium-nickel-nitrogen stainless steel is more complicated: some are non-magnetic, some are magnetic, and some are non-magnetic in the longitudinal plane and magnetic in the transverse plane. Therefore, although magnets can basically distinguish between chromium stainless steel and chromium-nickel stainless steel, they cannot correctly distinguish some special steel grades, let alone specific steel grades.

Update other authentication methods tomorrow！