316 stainless 1

[rck329]

Hello all,

Can anyone tell me what the difference is between "regular" 316/316L stainless, and "implantable grade" 316/316L?

Is this just a marketing ploy by the steel companies, or is there some discernable difference (i.e. - tighter composition tolerances, clean room handling, lower contaminant requirements, etc)

thanks for any help

Ryan

Lifecor Inc
Pittsburgh, PA

 

[Speedy]

The later has being FDA approved for implantation, simple as that.

So it's not just a question of the controls involved in production (GMP) but whether approval has being sought or not.

I have seen materials which are approved for 'skin contact' but not approved for implantation. The clinical trials involved for implantation are obviously much more involved.

Check out ISO 10993.

Hope this is of some help.

Cheers,
Speedy

 

[erwinito]

316 L is refered to "coming in sheets, flat sheets" ususaly used for tanks - 316 is refered to tubing and pipe ususaly.

erwin- aussie chem eng

 

[Ety]

According to a book I have (biomaterials/Ratner), the most common implantation grade are ASTM F138&F139 which specify in their compostion no more than 0.025MAX P and 0.01 max for S.

 

[FourJawChuck]

316L is a low carbon variant of 316, hence the "L". The main difference between implantable grades of stainless and pedestrian grades is the tracking process during manufacture of the raw material, much like ISO regulations they require the steel must be traceable from billet to fabricated part with all steps in between recorded.

As ETY pointed out this designation of stainless is not used much in implants anymore, the major medical MFG's have developed more stable and stronger variants that are proprietary to each manufacturer.