SURGICAL

7. The Materials Used in Manufacturing
7.1 Stainless Steel
The majority of KMedic instruments are manufactured from what is
known as “stainless steel”. Stainless steel is not truly “stainless”, but
rather a highly corrosion and rust-resistant alloy. The metal is extremely
strong and durable and, more importantly, has a characteristic ability to
form protective or “passivation” layers.
There are over 80 types of stainless steel manufactured, but only about a
dozen of them are useful in making surgical instruments. The choice of
steel is determined according to the desired flexibility, hardness, tensile
strength and malleability. Some types of steel can be hardened, others
cannot, depending primarily on the carbon content of the steel. The
types are composed of varying amounts of iron ore and chromium. It is
the large quantities of chromium which give the steel its “stainless”
properties. The chromium forms a thin layer on the surface, known as a
“passive layer,” which protects against corrosion. This layer acts as an
invisible patina and with correct care and handling, repeated use and
exposure to air, the instruments become increasingly corrosion resistant.
Many KMedic surgical instruments, including forceps, rongeurs and
curettes, are made of the German steel type known as “1.4021”. This
type is approximately equivalent to the American steel type 420.
Steel type 1.4021 is composed primarily of iron. The other components
are as follows:
Carbon 0.17-0.25%
Silicon ≤ 1.0%
Manganese ≤ 1.0%
Phosphorous ≤ 0.045%
Sulphur ≤ 0.043%
Chromium 12.0-14.0%
While every effort is made during the manufacturing process to ensure
that the instruments are corrosion resistant, the key to longevity is proper
maintenance. When not properly treated, stainless steel can rust and
stain, reducing the life of the instrument or rendering it useless. For
more detailed information on instrument care, see “KMedic Instrument
Care Instructions”, Section 12.
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