We offer this high quality austenitic stainless steel for spring applications. To keep costs at a minimum this alloy is supplied from an electric-arc air melted process. Localized variations in chemistry can cause slight changes in ultimate tensile strength when drawing to fine wire.
|FWM Avg. Wt. %||ASTM A313|
Modulus of Elasticity
28.0 x 106 psi
16.3 W/m K (100°C)
In wire form, cold worked 302 will gain tensile strength when stress relieved at 350-427°C for 4-6 hours. A reducing atmosphere is preferred, but inert gas can be used. 302 will fully anneal at 1010-1121°C in just a few minutes. There is a carbide precipitation phenomenon that occurs between 427 and 899°C that reduces the corrosion resistance of the alloy.
American Society for Testing Materials (ASTM) has described a test method to ensure the alloy has not been damaged.
302 alloy is the same as 304 alloy except for the 0.12% carbon maximum. In 304 the maximum carbon is 0.08%. Technically, all 304 alloy meets the requirements of 302 alloy, but not all 302 can meet 304 chemistry. Practically, this means in general 302 is harder than 304 with the same amount of cold work. End uses for 302 include stylets, catheters, guidewires, springs and needles.
|% Cold Work||Y.S. (psi)||U.T.S. (psi)||
(10" gage length)
Stainless steels develop a highly polished appearance as they are drawn to fine diameters. Surface roughness can be less than 5 microinches RMS when processed using single crystal natural diamond dies and measured with a profilometer. Diameters over 0.040" are finished with polycrystalline dies and exhibit a rougher surface than natural diamond dies. Diameters over 0.100" have an even rougher surface because they are drawn with carbide dies. Additional finish treatments can enhance the surface of the wire.