Terminology of Instruments

 

TERMINOLOGY:
AISI:
AISI (American Iron and Steel Institute) has identified the various formulations of steel and catalogued using a number system. Various materials used in surgical instrumentation have AISI numbers, like AISI 304, AISI 316L,  AISI 410/410X, AISI 420A, AISI 420B, AISI 440C.
ASTM:
ASTM (American Society of Testing and Materials) establish standards and specifications for numerous materials, both metallic and non-metallic. Some materials have an AISI number and some ASTM number.
Austenitic:
Series 300 Stainless Steels are Austenitic or non-hard enable or non-magnetic. The carbon content is as low as 0.08% that means these metals cannot be heat hardened and will not hold a strong cutting edge. However, it may be 'work hardened' through machining or forming. The presence of almost 18 % chromium and 8 % nickel makes these metals highly corrosion resistant and guarantee a brilliant shine. The term 18-8 stainless is used to describe this series.
Martensitic:
Series 400 Stainless Steel alloys are magnetic type and heat hard enable. These have relatively high carbon and low chromium percentages, along with traces of manganese (Mn), silicon (Si), sulphur (S), phosphorous (P), nickel (Ni) Molybdenum (Mo) etc endowing the metal with specific properties. Their use is a necessity whenever strength and temper are required. The degree of hardness depends largely on the carbon level. This series is used in most O.R quality instruments, cutting and non-cutting, because it has a high tensile strength, can hold edge for a long time and is corrosion resistant. However, as there is little or no nickel in this series it is susceptible to corrosion if not looked after properly.
INTERNATIONAL STANDARDS: 
BS 5194: Part 1 DIN 58298 ISO 7153-1
STAINLESS STEELS: 
This is a relatively modern British innovation that has become in universal use for steel instruments. It reaches the factories in the form of bars and sheets. Looking at these lengths of rough and dark gray material, one wonders how it will be fashioned into beautifully finished instruments. Such a transformation reveals craftsmanship at its best. 
STAINLESS STEEL TYPE AISI 304:
This material is easy to machine and form. Instruments or components that do not need to be hardened, such as speculums, retractor blades, hollow handles, hospital hollow wares, nuts, screws and pins etc, are usually made from this grade. 
STAINLESS STEEL TYPE AISI 316L:
It is a very high purity alloy. 'L' stands for low carbon. It is also called SMO. It is a preferred material for making most orthopedic implants, such as plates and screws, nails, staples, prostheses and aneurysm clips etc. Certain instruments that have prolonged contact with implants also utilize this material to avoid transfer of dissimilar metal particles which could cause galvanic corrosion reaction on the implants. It is however important to know that metal implants and prostheses can sooner or later fail since no metal has yet been developed that will equal the revitalizing durability of living bone.
STAINLESS STEEL TYPE AISI 410:
This is a most commonly used grade for the manufacture of non-cutting instruments. Typical examples are hemostats, assorted forceps, and retractors and so on. It is easy to work with and has Rockwell Hardness in the range of C-40 to C-45. It is a misconception that this grade is inferior in any way as it clearly complies with the British, German and International Standards for application in surgical instruments.
STAINLESS STEEL TYPE AISI 420 & 440:
These are useful grades for cutting instruments such as scissors, knives, chisels, ronguers, bone cutters, bone drills and taps etc. AISI 420 can get Rockwell Hardness in the range of C-48 to C-50 but if hardness around C-55 is required then grade AISI 440 with more carbon is appropriate. 
TITANIUM:  
Type ASTM F67 - Commercially Pure grades 1, 2 and 4. It has the same strength as steel but weighs only 60% of the steel. It is highly corrosion resistant but very difficult to work with. Some microsurgery instruments, mandibular implants and weight bearing hip prostheses are made from it. Its biocompatibility is far more superior to any other currently employed implant material. It can be finished in a distinct blue color but repeated autoclaving may give it a reddish tinge.
TUNGSTEN CARBIDE: 
GRADE GC20 This is the hardest man made material, sometime also referred to as diamond. It has a Rockwell of C-86. Cemented carbide is often called hard metal. Its inserts are sintered in the jaws of high wearing instruments such as needle holders, scissors and wire cutters. Traditionally these instruments are partly gold-plated for recognition.
OTHER MATELS: 
There are also many non-ferrous materials that are used in instruments for their specific properties. They may be easier to machine or form and more suitable for procedures or budget.
STERLING SILVER:
It is 92.5% pure silver (Ag). Current uses include trachea tubes, probes for eyes and hemostatic clips. Silver will turn black with oxide. This does not interfere with the function of the instrument. A bit of rub with or without silver polish or elbow grease will bring the original shine back. These instruments should be handled carefully as they are expensive as well as delicate.
GERMAN SILVER:
An alloy of silver and nickel that is less expensive and is used as an alternative to Sterling Silver. It is also more durable and does not turn black after autoclaving. 
BRASS AND COPPER:
Free cutting brass type 360 and nickel-copper Class A or B are easily formed, molded and welded therefore useful for making instruments that are otherwise hard to make from steel or require malleable features. Certain instruments made traditionally in these soft metals are proctoscopes, malleable uterine sounds and retractor blades, catheters and cannulas. In order to enhance surface wear these are usually plated.
ALUMINUM:
There are many hard and soft grades. With its excellent heat dissipation capacity along with durability and lightweight it is employed for making the container system for sterilization and storage. We offer a durable yet economical system. Aluminum requires a protective layer by hard anodizing that can also be in different colors for identification. Some instrument handles, mallet heads and splints are also made of aluminum. 
NON-METAL MATERIALS:  
Rubber, Plastic, Silicon and Tufnol are increasingly used in a wide variety of application, both reusable and disposable. Some of the useful characteristics are toughness, flexibility, resilient, resistant to chemicals, insulating, no moisture absorption, heat deformation, high impact strength, easy fabrication and low cost etc. In fact the possibilities are endless. Plastic items are gradually enabling a new wave of convenience and cost reduction in the operating room, a trend that will undoubtedly continue to grow with the passage of time. The use of latex rubber, however, has been discouraged because it contains certain protein that is said to cause skin allergy to some patients and hospital staff. No significant hazards are expected from silicon products under normal conditions of handling and use.
PLATING:
Carbon steel and non-ferrous metals instruments are protected from staining or discoloring by plating of various types. Until the advent of stainless steel most surgical instruments were plated. However many instruments are still more economical or effective to make plated. Mixing of plated instruments with stainless steel instruments in the reprocessing cycle should be avoided as it may result in transference of chrome to stainless that will look like stains. All plated instruments should be routinely checked to ensure there are no cracks or worn areas in the surface. In recent years the use of ultrasonic cleaning has hastened the demise of plated instruments as it tends to strip the plating from the base metal.
SILVER PLATING:
Instruments or components made of copper or brass can be plated with silver by electrodeposited coating. To enable the final silver deposit to adhere it will follow a primary coating of silver strike solution, nickel or copper plating. The silver plating shall not be less than 0.0010 inch in thickness. It is especially suitable on malleable instruments because the layer of silver plating is so thin it does not crack or chip when instrument is bent. Silver plating may turn black with silver oxide and may be given a good rub to get the shine back. 
NICKLE PLATING:
Nickel adheres very well to carbon steel and is not removed easily. The surface is made free from all flaws or defects which will be detrimental to the final finish. Cutting edges are ground to remove all plating. There are not many instruments made with carbon steel these days, except perhaps for veterinary use or some general-purpose scissors. Moisture will act rather quickly to first stain and then corrode these instruments.
CHROME PLATING :
Carbon steel, copper and brass are all base metals that can be chrome plated. Finish on all edges and surfaces shall be uniform and free from burrs, sharp edges (except where required), crevices, grind marks, rough areas, cracks and overlaps. Chrome plating often has a layer of copper or nickel underneath and therefore protects instruments longer from corrosion and discoloration. 
BLACK CHROME PLATING :
Black finish makes work easier under microscope or extra lighting because of lack of glare. Until recently, the black or ebonized finish was achieved by dipping in a sodium salt solution and then baking in oven. These salts, however, have now been reclassified as very toxic and therefore unsafe to use. There are also some very strong disinfectants also now available that can strip this type of black finish completely. We have therefore abandoned this process and may only be able to offer instruments ebonized in Europe if necessary.

TERMINOLOGY:

AISI:

AISI (American Iron and Steel Institute) has identified the various formulations of steel

and catalogued using a number system. Various materials

used in surgical instrumentation have AISI numbers, like AISI 304, AISI 316L,  

AISI 410/410X, AISI 420A, AISI 420B, AISI 440C.

 

ASTM:

ASTM (American Society of Testing and Materials) establish standards and specifications

for numerous materials, both metallic and non-metallic.

Some materials have an AISI number and some ASTM number.

 

Austenitic:

Series 300 Stainless Steels are Austenitic or non-hard enable or non-magnetic.

The carbon content is as low as 0.08% that means these metals cannot be heat

hardened and will not hold a strong cutting edge. However, it may be 'work hardened'

through machining or forming. The presence of almost 18 % chromium and 8 % nickel

makes these metals highly corrosion resistant and guarantee a brilliant shine.

The term 18-8 stainless is used to describe this series.

 

Martensitic:

Series 400 Stainless Steel alloys are magnetic type and heat hard enable. These have

relatively high carbon and low chromium percentages, along with traces of manganese (Mn),

silicon (Si), sulphur (S), phosphorous (P), nickel (Ni) Molybdenum (Mo) etc endowing the

metal with specific properties. Their use is a necessity whenever strength and temper are

required. The degree of hardness depends largely on the carbon level. This series is used

in most O.R quality instruments, cutting and non-cutting, because it has a high tensile

strength, can hold edge for a long time and is corrosion resistant. However, as there is

little or no nickel in this series it is susceptible to corrosion if not looked after properly.

 

INTERNATIONAL STANDARDS: 

BS 5194: Part 1 DIN 58298 ISO 7153-1

 

STAINLESS STEELS: 

This is a relatively modern British innovation that has become in universal use for steel

instruments. It reaches the factories in the form of bars and sheets. Looking at these

lengths of rough and dark gray material, one wonders how it will be fashioned into

beautifully finished instruments. Such a transformation reveals craftsmanship at its best. 

 

STAINLESS STEEL TYPE AISI 304:

This material is easy to machine and form. Instruments or components that do not

need to be hardened, such as speculums, retractor blades, hollow handles,

hospital hollow wares, nuts, screws and pins etc, are usually made from this grade. 

 

STAINLESS STEEL TYPE AISI 316L:

It is a very high purity alloy. 'L' stands for low carbon. It is also called SMO. It is a

preferred material for making most orthopedic implants, such as plates and screws,

nails, staples, prostheses and aneurysm clips etc. Certain instruments that have

prolonged contact with

implants also utilize this material to avoid transfer of dissimilar metal particles

which could cause galvanic corrosion reaction on the implants.It is however important

to know that metal implants and prostheses can sooner or later fail since no metal

has yet been developed that will equal the revitalizing durability of living bone.

 

STAINLESS STEEL TYPE AISI 410:

This is a most commonly used grade for the manufacture of non-cutting instruments.

Typical examples are hemostats, assorted forceps, and retractors and so on. It is easy

to work with and has Rockwell Hardness in the range of C-40 to C-45. It is a misconception

that this grade is inferior in any way as it clearly complies with the British, German and

International Standards for application in surgical instruments.

 

STAINLESS STEEL TYPE AISI 420 & 440:

These are useful grades for cutting instruments such as scissors, knives, chisels, ronguers,

bone cutters, bone drills and taps etc.

AISI 420 can get Rockwell Hardness in the range of C-48 to C-50 but if hardness around C-55

is required then grade AISI 440 with more carbon is appropriate. 

 

TITANIUM:  

Type ASTM F67 - Commercially Pure grades 1, 2 and 4. It has the same strength as steel but

weighs only 60% of the steel. It is highly corrosion resistant but very difficult to work with.

Some microsurgery instruments, mandibular implants and weight bearing hip prostheses

are made from it. Its biocompatibility is far more superior to any other currently employed

implant material. It can be finished in a distinct blue color but repeated autoclaving may give

it a reddish tinge.

 

TUNGSTEN CARBIDE: 

GRADE GC20 This is the hardest man made material, sometime also referred to as diamond.

It has a Rockwell of C-86. Cemented carbide is often called hard metal. Its inserts are sintered

in the jaws of high wearing instruments such as needle holders, scissors and wire cutters.

Traditionally these instruments are partly gold-plated for recognition.

 

OTHER MATELS: 

There are also many non-ferrous materials that are used in instruments for their specific

properties. They may be easier to machine or form and more suitable for procedures or budget.

 

STERLING SILVER:

It is 92.5% pure silver (Ag). Current uses include trachea tubes, probes for eyes and hemostatic

clips. Silver will turn black with oxide. This does not interfere with the function of the instrument.

A bit of rub with or without silver polish or elbow grease will bring the original shine back.

These instruments should be handled carefully as they are expensive as well as delicate.

 

GERMAN SILVER:

An alloy of silver and nickel that is less expensive and is used as an alternative to Sterling

Silver. It is also more durable and does not turn black after autoclaving. 

 

BRASS AND COPPER:

Free cutting brass type 360 and nickel-copper Class A or B are easily formed, molded and

welded therefore useful for making instruments that are otherwise hard to make from steel

or require malleable features. Certain instruments made traditionally in these soft metals

are proctoscopes, malleable uterine sounds and retractor blades, catheters and cannulas.

In order to enhance surface wear these are usually plated.

 

ALUMINUM:

There are many hard and soft grades. With its excellent heat dissipation capacity along

with durability and lightweight it is employed for making the container system for

sterilization and storage. We offer a durable yet economical system. Aluminum

requires a protective layer by hard anodizing that can also be in different colors for

identification. Some instrument handles, mallet heads and splints are also made

of aluminum. 

 

NON-METAL MATERIALS:  

Rubber, Plastic, Silicon and Tufnol are increasingly used in a wide variety of application,

both reusable and disposable. Some of the useful characteristics are toughness,

flexibility, resilient, resistant to chemicals, insulating, no moisture absorption, heat

deformation, high impact strength, easy fabrication and low cost etc. In fact the

possibilities are endless. Plastic items are gradually enabling a new wave of

convenience and cost reduction in the operating room, a trend that will undoubtedly

continue to grow with the passage of time. The use of latex rubber, however, has been

discouraged because it contains certain protein that is said to cause skin allergy to some

patients and hospital staff. No significant hazards are expected from silicon products under

normal conditions of handling and use.

 

PLATING:

Carbon steel and non-ferrous metals instruments are protected from staining or discoloring

by plating of various types. Until the advent of stainless steel most surgical instruments

were plated. However many instruments are still more economical or effective to make

plated. Mixing of plated instruments with stainless steel instruments in the reprocessing

cycle should be avoided as it may result in transference of chrome to stainless that will

look like stains. All plated instruments should be routinely checked to ensure there

are no cracks or worn areas in the surface. In recent years the use of ultrasonic cleaning

has hastened the demise of plated instruments as it tends to strip the plating from the

base metal.

 

SILVER PLATING:

Instruments or components made of copper or brass can be plated with silver by

electrodeposited coating. To enable the final silver deposit to adhere it will follow a primary

coating of silver strike solution, nickel or copper plating. The silver plating shall not be less

than 0.0010 inch in thickness. It is especially suitable on malleable instruments because

the layer of silver plating is so thin it does not crack or chip when instrument is bent.

Silver plating may turn black with silver oxide and may be given a good rub to get

the shine back. 

 

NICKLE PLATING:

Nickel adheres very well to carbon steel and is not removed easily. The surface is

made free from all flaws or defects which will be detrimental to the final finish.

Cutting edges are ground to remove all plating. There are not many instruments made

with carbon steel these days, except perhaps for veterinary use or some general-purpose

scissors. Moisture will act rather quickly to first stain and then corrode these instruments.

 

CHROME PLATING:

Carbon steel, copper and brass are all base metals that can be chrome plated.

Finish on all edges and surfaces shall be uniform and free from burrs, sharp edges

(except where required), crevices, grind marks, rough areas, cracks and overlaps.

Chrome plating often has a layer of copper or nickel underneath and therefore protects

instruments longer from corrosion and discoloration. 

 

BLACK CHROME PLATING:

Black finish makes work easier under microscope or extra lighting because of lack of glare.

Until recently, the black or ebonized finish was achieved by dipping in a sodium salt solution

and then baking in oven. These salts, however, have now been reclassified as very toxic and

therefore unsafe to use. There are also some very strong disinfectants also now available t

hat can strip this type of black finish completely. We have therefore abandoned this process

and may only be able to offer instruments ebonized in Europe if necessary.

 

 

News Updates

2016-10-10

Rafique Enterprises is one of the leading and most experienced manufacturing company dealing with Surgical, Dental, Veterinary and Beauty Care instruments, based in Sialkot, Pakistan. Rafique Enterprises pride itself to be a company giving utmost assurance towards achieving our customer´s trust. Company management always eager and welcome the instructions and suggestions of its customers and employees that is way the quality remains at its peak every time. 

 

 

Company Information

We are manufacturers and exporters of all kinds

of single use surgical, general surgical, dental,

orthodontic, ophtalmic, orthopedic, veterinary,

fishing and beauty care instruments. We have

huge range of eyelash extension tweezers and

tools.