A number of different metals are used for making different varieties of steel alloys. Different metals in varying combinations confer characteristic properties to different steel types. Commonly used alloying elements include Carbon, Chromium, Nickel, Molybdenum and Tungsten.
In surgical instrument manufacturing, chromium is the most important alloying element and at least 10.5% chromium should be present in the alloy to allow formation of protective layer on steel surface. More chromium means more protection of the surgical instrument. Chromium renders surgical instruments passive and therefore prevents oxidation.
The presence of Nickel in steel alloys improves corrosion resistance and workability. At least 8% to 9% nickel is considered essential, and, the presence of nickel beyond this percentage further improves corrosion resistance and workability.
Molybdenum and tungsten
The presence of molybdenum and tungsten enables the steel alloy to resist crevice formation and pitting. Molybdenum when added to martensitic steel types contributes to improving high temperature strength.
Carbon is considered to be an austenite stabilizer and its presence enhances the strength of steel. However, it has a negative impact on corrosion resistance.
To read about the Steel Grades used on Surgical Instrument Manufacturing, click here.