Stainless Steel Alloys
There are many alloys of stainless steel. Below are some of the key properties of many of the popular ones.
Stainless steel 15-5 PH is often used in gears, cams, and aircraft parts. It combines high strength and wear resistance. 15-5 PH can be heat treated at low temperatures to increase mechanical properties. It is magnetic.
Stainless steel 17-4 PH maintains high strength and wear resistance. It has improved corrosion resistance over 15-5 PH. 17-4 PH can be strengthened by precipitation hardening at low temperatures. It is magnetic.
Stainless steel 17-7 PH has high strength and good response to heat-treating. 17-7 PH has moderate corrosion resistance.
Stainless steel 301 is the most strain-hardenable chromium-nickel stainless steel. It has better wear resistance and fatigue strength than 304. Type 301 retains strength while stretching like 1095 steel. It is has good weldability and temperature resistance. It may be slightly magnetic and cannot be heat treated.
Stainless steel 302 has slightly higher strength than Type 304 with the same corrosion resistance. It cannot be heat treated.
Stainless steel 303 is easy to machine. It has good corrosion and temperature resistance. May become slightly magnetic. Can't be heat treated.
Stainless steel 304 is the most widely used stainless steel. It has good weldability and formability. Type 304 has good corrosion resistance and may become slightly magnetic. It is not heat treatable.
Stainless steel 316 has above normal corrosion resistance, good weldability and temperature resistance. May become slightly magnetic. Cannot be heat treated.
Stainless steel 410 can be heat treated for extra hardness and improved wear resistance. It is not recommended for highly corrosive environments nor for welding.
Stainless steel 416 offers better machinability than 410. Type 416 can be heat treated and is magnetic.
Stainless steel 420 has excellent polishability for use in mold tooling and high hardness. Type 420 can be heat treated and is magnetic.
Stainless steel 420V has improved wear resistance compared to 420C and improves corrosion resistance. Type 420V can be used in place of tool steels for better corrosion resistance.
Stainless steel 430 is a lower cost alloy with good formability. It is magnetic and cannot be heat treated. It is not recommended for temperature extremes or outdoor use and is more often used for aesthetic purposes.
Stainless steel 440A has greater hardenability than Type 420 and greater toughness than Type 440C yet provides good corrosion resistance. Type 440A is often used for cutlery, valve parts, and surgical instruments.
Stainless steel 440C, when heat treated is one of the hardest stainless steels and has good wear resistance. It is magnetic. Type 440C is ideal for bearings, valve parts, and knife blades.
Stainless steel 430 has good formability and is magnetic. It cannot be heat treated and is for room temperature aesthetic applications.
Stainless steel 301 is the most strain-hardenable chromium-nickel stainless steel. It has better wear resistance and fatigue strength than Type 304. Type 301 retains strength while stretching like 1095 steel. It has good weldability and temperature resistance. May be slightly magnetic. Cannot be heat treated.
