This austenitic stainless steel is initially electric-arc melted. Then as a refinement to the purity and homogeneity of the metal, 304V is Vacuum Arc Remelted (VAR). This process yields a more uniform chemistry with minimal voids and contaminants.
In wire form, 304V will gain tensile strength when stress relieved at 350-427°C. A reducing atmosphere is preferred but inert gas can be used. 304V 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. The American Society for
Testing Materials has described a test method to ensure the alloy has not been damaged.
This alloy is the most popular for non-implantable medical devices. The ease of joining with solder or welding, combined with excellent strength, makes it desirable. This alloy is also one of the least expensive medical materials. Some examples of end products are stylets, catheters, guidewires, springs and needles. Fort Wayne Metals routinely produces cables, strands, flat wire and shapes from this alloy.
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.