Surgical stainless steel
Encyclopedia
Surgical stainless steel is a specific type of stainless steel
, used in medical applications, made out of several components: chromium
, nickel
and molybdenum
.
The chromium
gives the metal its scratch resistance and corrosion
resistance. The nickel
provides a smooth and polished finish. The molybdenum
gives greater hardness and helps maintain a cutting edge.
Although there are myriad variations in the recipes, there are two main varieties of stainless steel: martensitic
and austenitic
; see the stainless steel
article.
The word 'surgical' refers to the fact that these types of steel are well-suited for making surgical instruments: they are easy to clean and sterilize
, strong, and corrosion-resistant. The nickel/chrome/molybdenum alloys are also used for orthopaedic implants as aids in bone repair, and as a structural part of artificial heart valves and other implants. However, immune system reaction to nickel is a potential complication. In some cases today titanium
is used instead in procedures that require a metal implant which will be permanent. Titanium is a reactive metal, the surface of which quickly oxidizes on exposure to air, creating a microstructured stable oxide surface. This provides a surface into which bone can grow and adhere in orthopaedic implants but which is incorrodible after implant. Thus steel may be used for temporary implants and the more expensive titanium for permanent ones.
Most surgical equipment is made out of martensitic steel—it is much harder than austenitic steel, and easier to keep sharp. Depending on the type of equipment, the alloy
recipe
is varied slightly to get more sharpness or more strength.
Implant
s and equipment that are put under pressure (bone
fixation screw
s, prostheses
, body piercing jewelry
) are made out of austenitic steel, often 316L and 316LVM compliant to ASTM F138, because it is less brittle.
316 surgical steel is used in the manufacture and handling of food and pharmaceutical products where it is often required in order to minimize metallic contamination.
ASTM F138-compliant steel is also used in the manufacture of body-piercing jewelry and body modification
implants.
Stainless steel
In metallurgy, stainless steel, also known as inox steel or inox from French "inoxydable", is defined as a steel alloy with a minimum of 10.5 or 11% chromium content by mass....
, used in medical applications, made out of several components: chromium
Chromium
Chromium is a chemical element which has the symbol Cr and atomic number 24. It is the first element in Group 6. It is a steely-gray, lustrous, hard metal that takes a high polish and has a high melting point. It is also odorless, tasteless, and malleable...
, nickel
Nickel
Nickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...
and molybdenum
Molybdenum
Molybdenum , is a Group 6 chemical element with the symbol Mo and atomic number 42. The name is from Neo-Latin Molybdaenum, from Ancient Greek , meaning lead, itself proposed as a loanword from Anatolian Luvian and Lydian languages, since its ores were confused with lead ores...
.
The chromium
Chromium
Chromium is a chemical element which has the symbol Cr and atomic number 24. It is the first element in Group 6. It is a steely-gray, lustrous, hard metal that takes a high polish and has a high melting point. It is also odorless, tasteless, and malleable...
gives the metal its scratch resistance and corrosion
Corrosion
Corrosion is the disintegration of an engineered material into its constituent atoms due to chemical reactions with its surroundings. In the most common use of the word, this means electrochemical oxidation of metals in reaction with an oxidant such as oxygen...
resistance. The nickel
Nickel
Nickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...
provides a smooth and polished finish. The molybdenum
Molybdenum
Molybdenum , is a Group 6 chemical element with the symbol Mo and atomic number 42. The name is from Neo-Latin Molybdaenum, from Ancient Greek , meaning lead, itself proposed as a loanword from Anatolian Luvian and Lydian languages, since its ores were confused with lead ores...
gives greater hardness and helps maintain a cutting edge.
Although there are myriad variations in the recipes, there are two main varieties of stainless steel: martensitic
Martensite
Martensite, named after the German metallurgist Adolf Martens , most commonly refers to a very hard form of steel crystalline structure, but it can also refer to any crystal structure that is formed by displacive transformation. It includes a class of hard minerals occurring as lath- or...
and austenitic
Austenite
Austenite, also known as gamma phase iron, 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 ; other alloys of steel have different eutectoid temperatures...
; see the stainless steel
Stainless steel
In metallurgy, stainless steel, also known as inox steel or inox from French "inoxydable", is defined as a steel alloy with a minimum of 10.5 or 11% chromium content by mass....
article.
The word 'surgical' refers to the fact that these types of steel are well-suited for making surgical instruments: they are easy to clean and sterilize
Sterilization (microbiology)
Sterilization is a term referring to any process that eliminates or kills all forms of microbial life, including transmissible agents present on a surface, contained in a fluid, in medication, or in a compound such as biological culture media...
, strong, and corrosion-resistant. The nickel/chrome/molybdenum alloys are also used for orthopaedic implants as aids in bone repair, and as a structural part of artificial heart valves and other implants. However, immune system reaction to nickel is a potential complication. In some cases today titanium
Titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....
is used instead in procedures that require a metal implant which will be permanent. Titanium is a reactive metal, the surface of which quickly oxidizes on exposure to air, creating a microstructured stable oxide surface. This provides a surface into which bone can grow and adhere in orthopaedic implants but which is incorrodible after implant. Thus steel may be used for temporary implants and the more expensive titanium for permanent ones.
Most surgical equipment is made out of martensitic steel—it is much harder than austenitic steel, and easier to keep sharp. Depending on the type of equipment, the alloy
Alloy
An alloy is a mixture or metallic solid solution composed of two or more elements. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may or may not be homogeneous in distribution, depending on thermal history...
recipe
Recipe
A recipe is a set of instructions that describe how to prepare or make something, especially a culinary dish.-Components:Modern culinary recipes normally consist of several components*The name of the dish...
is varied slightly to get more sharpness or more strength.
Implant
Implant (medicine)
An implant is a medical device manufactured to replace a missing biological structure, support a damaged biological structure, or enhance an existing biological structure. Medical implants are man-made devices, in contrast to a transplant, which is a transplanted biomedical tissue...
s and equipment that are put under pressure (bone
Bone
Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...
fixation screw
Screw
A screw, or bolt, is a type of fastener characterized by a helical ridge, known as an external thread or just thread, wrapped around a cylinder. Some screw threads are designed to mate with a complementary thread, known as an internal thread, often in the form of a nut or an object that has the...
s, prostheses
Prosthesis
In medicine, a prosthesis, prosthetic, or prosthetic limb is an artificial device extension that replaces a missing body part. It is part of the field of biomechatronics, the science of using mechanical devices with human muscle, skeleton, and nervous systems to assist or enhance motor control...
, body piercing jewelry
Body piercing jewelry
Body piercing jewelery is jewelery manufactured specifically for use in body piercing.Originally, hardly any other jewellery than circular earrings were used in modern Western body piercing. As the body piercing became more of a fashion, a vast amount of specially crafted jewellery became available...
) are made out of austenitic steel, often 316L and 316LVM compliant to ASTM F138, because it is less brittle.
316 surgical steel is used in the manufacture and handling of food and pharmaceutical products where it is often required in order to minimize metallic contamination.
ASTM F138-compliant steel is also used in the manufacture of body-piercing jewelry and body modification
Body modification
Body modification is the deliberate altering of the human body for any non-medical reason, such as aesthetics, sexual enhancement, a rite of passage, religious reasons, to display group membership or affiliation, to create body art, shock value, or self expression...
implants.