As far as I know, many friends in screw industry are interested about the material classification of stainless steel machine screw. The material classification of stainless steel screw include austenitic stainless steel, ferritic stainless steel, martensitic stainless steel and precipitation-hardening stainless steel. What performance do they respectively have? I will list them out.
1.Ferritic stainless steel
Stainless steel screw adopt the type 430 ordinary chrome steel. Its corrosion resistance and heat resistance is better than type 410, and it is magnetic. But it can not be strengthened by heat treatment. It is suitable for the stainless steel screw which has high requirements of corrosion resistant and heat resistant performance and general requirements of strength.
2.Martensitic stainless steel
Type 410 and type 410 can be strengthened by heat treatment. Its hardness is in 35 ~ 45 HRC, and its machining performance is good. It is used for the stainless steel machine screw with general purposes of heat resistant and corrosion resistant.
3.Precipitation-hardening stainless steel
17-4PH and PH15-7Mo, they can get higher strength than the usual type 18-8 stainless steel. Therefore, it is used for the stainless steel machine screw with high strength and corrosion resistant.
4.Austenitic stainless steel
The commonly used four brands are 302, 303, 304 and 305, namely so-called "18-8" type of austenitic stainless steel. Both its corrosion resistance and mechanical properties are similar. The starting point of choosing is the production technology of the machine screw. And method depends on the size and shape of the stainless steel screw, and depends on the quantity of production.