1. Color recognition.
ss 304 color recognition
Pickling stainless steel, the surface color is silvery white and clean: chrome-nickel stainless steel is silver-white jade; chrome stainless steel is white with a slight gray luster; the color of chrome-manganese-nitrogen stainless steel is similar to the light color of chrome-nickel stainless steel.
Unpickled stainless steel surface color: chrome-nickel steel is brown-white, chrome-steel is brown-black, and chrome-manganese-nitrogen is black (these three colors are related to the color of heavy oxidation).
Cold rolled unannealed chrome-nickel stainless steel with silver-white reflective surface.
2. Magnet identification.
ss 304 magnet identification
Magnets can basically differentiate between 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 become magnetic after cold working.
However, high manganese steel with high manganese content is non-magnetic, while the magnetic situation of chromium-nickel-nitrogen stainless steel is more complicated: some are non-magnetic, some are longitudinally non-magnetic, and some are longitudinally non-magnetic. Horizontal plane.
Therefore, the magnet method can basically distinguish chromium stainless steel and chromium-nickel stainless steel, but cannot correctly distinguish some special properties of steel.
3. Identification of copper sulfate.
First remove the oxide layer on the steel, then drop a drop of water, wipe it with copper sulfate, if it does not change color, it is generally stainless steel; if it turns purple, the non-magnetic one is high manganese steel, and the magnetic one is carbon steel or low alloy steel.
