Surgical stainless steel is a grade of
stainless steel used in biomedical applications. The most common "surgical steels" are
austenitic
Austenite, also known as gamma-phase iron (γ-Fe), is a metallic, non-magnetic allotrope of iron or a solid solution of iron with an alloying element. In plain-carbon steel, austenite exists above the critical eutectoid temperature of 1000 K ...
SAE 316 stainless and
martensitic
Martensite is a very hard form of steel crystalline structure. It is named after German metallurgist Adolf Martens. By analogy the term can also refer to any crystal structure that is formed by diffusionless transformation.
Properties
Mart ...
SAE 440, SAE 420, and
17-4 stainless steels. There is no formal definition on what constitutes a "surgical stainless steel", so product manufacturers and distributors often apply the term to refer to any grade of corrosion resistant steel.
Medical grade stainless
SAE 316 and
SAE 316L stainless steel, also referred to as ''
marine grade stainless
Marine grade stainless alloys typically contain molybdenum to resist the corrosive effects of NaCl or salt in seawater. Concentrations of salt in seawater can vary, and splash zones can cause concentrations to increase dramatically from the spray ...
'', is a
chromium
Chromium is a chemical element with the symbol Cr and atomic number 24. It is the first element in group 6. It is a steely-grey, lustrous, hard, and brittle transition metal.
Chromium metal is valued for its high corrosion resistance and hardne ...
,
nickel,
molybdenum alloy
An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductility, ...
of steel that exhibits relatively good strength and corrosion resistance. 316L is the low carbon version of 316 stainless steel.
316L in particular is biocompatible when produced to ASTM F138 / F139. It is a common choice for biomedical
implants, as well as
body piercings
Body piercing, which is a form of body modification, is the practice of puncturing or cutting a part of the human body, creating an opening in which jewelry may be worn, or where an implant could be inserted. The word ''piercing'' can refer to ...
and
body modification
Body modification (or body alteration) is the deliberate altering of the human anatomy or human physical appearance. In its broadest definition it includes skin tattooing, socially acceptable decoration (''e.g.'', common ear piercing in many so ...
implants.
Immune system reaction to nickel is a potential complication of stainless steel usage within the human body.
There are nickel-free
nitrogen-strengthened
austenitic
Austenite, also known as gamma-phase iron (γ-Fe), is a metallic, non-magnetic allotrope of iron or a solid solution of iron with an alloying element. In plain-carbon steel, austenite exists above the critical eutectoid temperature of 1000 K ...
stainless steel alloys available which address this concern.
316 surgical steel is also used in the manufacture and handling of food and pharmaceutical products where it is often required in order to minimize metallic contamination.
The corrosion resistance properties of all stainless steels is greatly enhanced by the
passivation process. ASTM A967
details this process.
Cutlery grade stainless
SAE 440 and SAE 420 stainless steels, known also by the name "Cutlery Stainless Steel", are
high carbon steels alloyed with chromium. They have very good corrosion resistance compared to other cutlery steels, but their corrosion resistance is inferior to 316 stainless. Surgical cutting instruments are often made from 440 or 420 stainless due to its high hardness coupled with acceptable corrosion resistance. This type of stainless steel may be slightly magnetic.
General surgical tools are made from other chromium-bearing stainless steels, such as
17-4. ASTM F899 contains a list of commonly used metals for
surgical instruments
A surgical instrument is a tool or device for performing specific actions or carrying out desired effects during a surgery or operation, such as modifying biological tissue, or to provide access for viewing it. Over time, many different kinds of ...
.
See also
*
Instruments used in general surgery
*
SAE International
SAE International, formerly named the Society of Automotive Engineers, is a United States-based, globally active professional association and standards developing organization for engineering professionals in various industries. SAE Internati ...
*
ASTM International
ASTM International, formerly known as American Society for Testing and Materials, is an international standards organization that develops and publishes voluntary consensus technical standards for a wide range of materials, products, systems, an ...
References
{{Authority control
Biomaterials
Stainless steel
Surgical instruments