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Stainless Steel Alloys
Today, hundreds of different alloy combinations
exist for the endless variety of applications which
utilize stainless and heat resisting steels. The
primary elements added to obtain the various
properties required in the steels include chromium,
nickel, manganese, silicon, molybdenum, and the
stabilizing elements of titanium columbium and
tantalum.
Stainless steel contains at least 10 percent
chromium, along with other elements to develop
specific properties. Depending on the quality of
the elements present in a stainless alloy, it will
have a metallurgical structure which will be
characteristic of the basic stainless steel groups.
Metallurgists refer to these groups as the martensitic
group, the ferritic group, the austenitic group and
the precipitation hardening group of stainless steels.
All standard austenitic alloys are given numbers in the
“200” and “300” series, while the martensitic and ferritic
alloys are numbered in the “400” series.
Passivation of Stainless Steel Alloys
Team Metal Finishing Specializes in the passivation
of 316, 316L and 304 Stainless Steel alloys. Unlike the
other two classes, they contain nickel in quantities
from 4 to 22 percent, while the percentage of
carbon is kept relatively low. This alloy structure makes
the austenitic group of stainless a prime canadate for
passivation.
304 Stainless Steel has chromium and nickel
increased and carbon lowered to reduce carbide
precipitation and increase corrosion resistance.
Lowering the carbon content also makes welding
easier.
316/316L Stainless Steel has molybdenum added to
improve corrosion resistance and high temperature
strength. The carbon content is also lowered to
improve welding performance.
Typical applications by alloy (300 series S.S)
Type 304
- Beer barrels (kegs)
- Chemical Equipment
- Coal hopper linings
- Cooling coils
- Cryogenic vessels and components
- Dairy equipment
- Evaporators
- Food handling equipment
- Milking machines
- Nuclear vessels and components
- Oil well filter screens
- Pressure vessels
- Sanitary fittings and valves
- Shipping drums
- Still tubes
- Textile dyeing equipment
- Hypodermic needles
- Feed-water tubing
Type 316/316L
- Chemical processing equipment
- Chemical storage and transportation tanks
- Food processing equipment
- Steam cooking kettles
- Oil refining equipment
- Paper pulp digesters and evaporators
- Petroleum refining equipment
- Pharmaceutical processing equipment
- Scrubbers for environmental control
- Soap and photographic handling equipment
- General applications in textile industry
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