Steels Used for Surgical Instruments

Different chemical compositions are suitable for different surgical instruments. BS 5194 : Part 1:1991 gives a more in depth breakdown for the uses, but as a basic guide, instruments should be manufactured from the following (a few examples are shown below):

Non-Hardenable (Austenitic) Stainless Steel, High Chromium. Austenitic Steels are non-magnetic and cannot be hardened
AISI 303 for Machining/turned parts

AISI 304 for bending, welding, containers and baskets

AISI 316 for containers/baskets

AISI 316LVM for implants

Hardenable (Martensitic) European Steels:

AISI 420S29 EN56B – Bow work, artery forceps, needle holders, dissecting forceps and clamps

AISI 420S37 EN56C – Bone cutters, punch forceps, scissors – anything that needs to hold an edge

AISI 420S45 EN56D – For knives, chisels, gouges and osteotomes. Small Ear, Nose and throat knives, scissors, super cut scissors, screwdrivers, micro and ophthalmic scissors.

As a general rule, the more a harder edge is required to be on the instrument for cutting, the more carbon the instrument will contain. The carbon allows the steel to be hardened, so it doesn’t bend during use and also can be sharpened so it retains its sharpness for cutting.

Chromium is the part of the composition of the steel that gives it the shiny chrome presentation. This also helps with rust resistance, along with nickel and the more chrome, the more it will resist corrosion.