Classification of stainless steel:
(1) according to the structure: martensitic stainless steel, iron surface stainless steel, austenitic stainless steel, double-phase stainless steel;
(2) according to the main chemical composition of steel: chromium stainless steel nickel stainless steel, chromium nickel molybdenum stainless steel, ultra-low carbon stainless steel.(For the production of fasteners mainly use 300 series austenitic stainless steel, the main chemical composition of this kind of stainless steel is 18% chromium and 8% nickel, that is generally known as 18-8 stainless steel, is a chromium nickel stainless steel series)
(3) the characteristics of austenitic stainless steel: no magnetic in the normal state, after cold processing slightly magnetic;At various temperatures, it can maintain its Ostian structure, no phase change, so it can not be hardened by heat treatment;However, when applied to cold working, it can harden and increase strength.
Its steel characteristics are described as follows:
302HQ: Low carbon, low nitrogen, low sulfur, very low work hardening rate, excellent cold processing, suitable for the use of complex shape, high molding difficulty.
304: moderate work hardening rate, suitable for general cold working and drawing, cold working performance is better.
304M: medium work hardening rate, suitable for general cold room processing and drawing.
304HC: Addition of copper instead of nickel reduces the work hardening rate of steel and maintains low magnetic conductivity.
SUS316: Add molybdenum for better corrosion resistance and pore corrosion resistance.
SUS316L: Low carbon, better corrosion resistance and cold workability than 316.
