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Type 304 stainless steel is basically the same as Type
302 except for a higher chromium and lower carbon content.
Its lower carbon minimizes chromium carbide precipitation
due to welding and its susceptibility to intergranular
corrosion. In many instances, Type 304 can be used in
the "as welded" condition while Type 302 must be annealed
in order to retain adequate corrosion resistance.
Type 304 has the same excellent combination of strength,
corrosion resistance and workability as Type 302, and
it costs the same. Consequently this type is widely used
and is more popular than type 302. |
Type 304L is an extra low carbon variation
of Type 302. The .03% maximum carbon content eliminate
carbide precipitation due to welding. Consequently,
the alloy can be used in the "as welded" condition even
in severe corrosive conditions. In many cases it eliminates
the necessity of annealing weldments except for applications
where stress relief is specified. Type 304L has slightly
lower mechanical properities than Type 304. |
| Available Forms
Types 304 and 304L stainless steel is available in:
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Bar
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Wire
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Sheet
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Strip
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Billets |
Specifications
The following specifications are generally applicable:
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| Property |
Type 304% |
Type 304L% |
| Carbon |
.08 max |
.03 max |
| Manganese |
2.00 max |
2.00 max |
| Phosporus |
.045 max |
.045 max |
| Sulfur |
.030 max |
.030 max |
| Silicon |
1.00 max |
1.00 max |
| Chromium |
18.0-20.0 |
18.0-20.0 |
| Nickel |
8.0-12.0 |
8.0-12.0 |
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Type 304L |
| Property |
Sheet & Strip |
Bar & Wire |
Sheet & Strip |
Bar & Wire |
| Ultimate tensile strength, psi |
85,000 |
85,000 |
80,000 |
80,000 |
| .2% Yield strength, psi |
35,000 |
35,000 |
30,000 |
30,000 |
| Elongation, % om 2" |
55 |
60 |
55 |
60 |
| Rockwell hardness |
B80 |
B80 |
N75 |
B75 |
| Reduction of area, % |
NA |
70 |
NA |
70 |
| Impact strength, Izod V Notch, ft-lbs |
NA |
100-120 |
NA |
100-120 |
| Endurance limit, psi |
NA |
34,000 |
NA |
34,000 |
| Typical Applications
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Low carbon Content of 304 and 304L
is more conducive to welding than type 302
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Applications include architectural
mouldings and trim and kitchen equipment
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Alloys are widely used for welded components
of processing equipment for textile |
Machinability
When machined, Types 304 and 304L will work-harden.
Therefore tools must not ride or glaze the surface without
cutting. Heavy feeds and slow speeds are recommended
Weldability
Both these stainless steels are readily welded by most
welding processes such as TIG, MIG and resistance welding.
However, all arc welding not using a shielded gas should
have the filler rods coated. Type 308 and 308L welding
rods are suggested for best results. |
Formability
Types 304 and 304L have very good drawability. Their
combination of low yield strength and high elongation
permits successful forming complex shapes. However,these
grades work harden rapidly. To relieve stresses
produced in severe forming spinning, parts should be full
annealled or stress-relief annelaed as soon as possible
after forming
Corrosion Resistance
Like Type 302, Types 304 and 304L stainless steel have
excellent resistance to a wide range of corrosive media
and to atmospheric exposures. The low carbon content
of Type 304 and especially 304L, by reducing or eliminating
carbide precipitation due to welding, makes these types
of stainless suitable for a much wider range of corrosive
service than Type 302. |
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