The main necessity of all types of surgical instruments from the surgeon's point of view is Resistance To Corrosion.Hence, while evaluating alloy for an instrument, it is extremely essential to consider this property.However,the other factors,pertaining to manufacturing such as Forge-ability ,Weld-ability,Machine-ability,Cost etc; are also important.
Both martensitic and austenitic stainless steel are used for the manufacturing of surgical instruments.The typical applications include:-
i- AISI-304 (For Sheet Metal Item)
ii-AISI-410 (For Homeostatic Forceps)
iii-AISI-420 (For Scissors And Ronguers)
iv-AISI-440 (For Knives And Dental Pliers)
The carbon content between 0.12 to 0.15 is sufficient for Forceps as the requirement of hardness is up to 40 HRC,but for cutting instruments like Scissors and Knives, the carbon content, must be at least between 0.30 to 0.35%.The Chromium content up to 13% is acceptable, as up to this range, corrosion can be controlled,provided proper fabrication polishing and cleaning methods are followed.
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