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Stainless Steels
| Stainless steels come in a wide variety of alloy combinations
for various applications. The most common alloys for passenger
rail vehicle design are given in the following standards. A
more detailed list of stainless steel types
follows the standards recommendations for additional information.
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| Standard: |
APTA SS-C&S-004-98
Standard for Austenitic Stainless Steel for Railroad Passenger
Equipment
| | Purpose: |
This standard covers the minimum properties of austenitic
stainless steels used in fabrication of passenger railroad
equipment. Principal grades of austenitic stainless steels
for railroad passenger equipment structural applications
are the low carbon types 201L, 20lLN and 301L, 301LN. Other
austenitic stainless steels may be applied where justified
by design considerations. This standard also includes requirements
and precautions for forming, welding, and handling of the
low carbon, austenitic stainless steel. |
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| Criteria: |
Specify compliance with standard |
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| Usage: |
Shall comply with applicable requirements of APTA SS-C&S-004-98
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| Standard: |
ASTM A666 - Standard Specification for
Annealed or Cold-Worked Austenitic Stainless Steel Sheet, Strip, Plate,
and Flat Bar
| | Purpose: |
This specification covers austenitic stainless steels in the annealed
and normally required cold-worked conditions for various structural,
architectural, pressure vessel, magnetic, cryogenic, and heat-resisting
applications. (This revision of Specification A 666 replaces prior
Specifications A 412 and A 177.)
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| Criteria: |
ASTM A666 is a specification with minimum requirements listed
to meet this standard, but must be further defined with the (AISI)
designation as listed in Table 1 (i.e. type 201, 301, 301L 302, 304,
304L, 316...) Additional requirements for carbodies may be low nitrogen
versions (i.e. AISI type 201L or 301LN, 301 LN shall not exceed 0.25%
Nitrogen.) Note: Intergranular corrosion may be tested with ASTM A
262
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| Usage: |
... Shall meet the requirements of ASTM A666, type XXX (or provide
the list of Table 1 for the vendor to select from)
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| Standard: |
ASTM A262 - Standard Practices
for Detecting Susceptibility to Intergranular Attack in Austenitic
Stainless Steels
| | Purpose: |
ASTM A262 is used to detect susceptibility to intergranular corrosion
in stainless steel. This test procedure covers five tests; Practice
A, B, C, E, and F.
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| Criteria: |
ASTM A262 Practice A is used as a pre-screening test for acceptance
testing of austenitic stainless steel, with other Practices used when
Practice A fails. For rail applications, Practice E covers most of
the alloys used. Typically used for structural stainless steel applications.
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| Usage: |
... shall be tested for susceptibility to intergranular corrosion
according to the requirements of ASTM A262, Practice X
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| Stainless
Steels Types and Common Applications
| 200 Series - Austenitic Chromium-Nickel-Manganese
Alloys |
| 201 |
Austenitic stainless steel that is hardenable through
cold working. It has a high work hardening rate, typically
used for automobile trim, etc. |
| 202 |
Austenitic, general purpose stainless steel similar to
302, typically used for kitchen equipment. |
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| 300 Series - Austenitic Chromium-Nickel
Alloys |
| 301 |
This stainless steel is highly ductile, for formed products.
It has a high work hardening rate,with good strength and
good weldability. Better wear resistance and fatigue strength
than 304. |
| 302 |
This is a general purpose stainless steel with comparable
corrosion resistance to 304, with slightly higher strength
due to additional carbon. Good for light duty springs and
general use. |
| 303 |
This stainless steel is a free machining version of 304
due to the addition of sulfur and phosphorus. Also referred
to as "A1" in accordance with ISO 3506-5. Good
for screw machine products. |
| 304 |
Lower carbon content than 302. This is a good general
purpose stainless steel and is the most common grade in
use. It is frequently know as the classic "18/8"
stainless steel. Also referred to as "A2" in accordance
with ISO 3506-5. |
| 304L |
This stainless steel is the 304 grade but a low-carbon
version specially modified for welding. |
| 305 |
Low work hardening rate, used for severe drawing operations,
spin forming, cold heading, etc. Commonly used for bowls,
coffee pots, etc. |
| 308 |
High alloy with high heat and corrosion resistance. This
stainless steel is used as the filler metal when welding
304 |
| 309 |
This stainless steel has a better temperature resistance
than 304, frequently used for heat exchanger and furnace
equipment. Also sometimes used as filler metal when welding
dissimilar steels. |
| 316 |
This stainless steel is the second most common grade (after
304). It has high corrosion resistance and high creep strength.
Typically used for food and surgical stainless steel uses.
316 steel is used in the manufacture and handling of food
and pharmaceutical products where it is often required in
order to minimize metallic contamination. |
| 321 |
This stainless steel is similar to 304 but lower risk
of weld decay due to addition of titanium. Stabilized for
weldments exposed to severe corrosion conditions. |
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| 400 Series - Ferritic and Martensitic
Chromium Alloys |
| 405 |
This stainless steel is a non-hardenable grade, ferritic.
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| 409 |
This stainless steel is the cheapest type, general purpose;
used in construction, automobile exhausts; ferritic (iron/chromium
only). |
| 410 |
This stainless steel is martensitic (high-strength iron/chromium).
General purpose, wear-resistant, but less corrosion-resistant.
Used for machine parts, pump shafts, etc. |
| 416 |
This stainless steel is a free-machining version of 410
(heavy cuts). Used for screw machine parts, etc. |
| 420 |
This stainless steel is a high-carbon version of 410,
martensitic, similar to the Brearley's original rustless
steel. Used for cutlery, surgical equipment. Excellent polishability.
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| 430 |
This stainless steel is a general purpose, non-hardenable
grade; ferritic. Used for decorative automotive trim, nitric
acid tanks, restaurant equipment. Good formability, but
with reduced temperature and corrosion resistance. |
| 440 |
This stainless steel is a higher grade of cutlery steel,
with more carbon in it, which allows for much better edge
retention when the steel is heat-treated properly. It
is hardenable to ~ Rockwell 58, making it one of the hardest
stainless steels.
Due to its toughness and relatively low cost, most display-only
and replica swords or knives are made of 440 stainless.
Also known as razor blade steel. Available in four grades:
440A, 440B, 440C, and the uncommon 440F (free machineable).
440A, Hardenable, good corrosion resistance, is the most
stain-resistant
440B, Cutlery grade, valve parts, instrument bearings
440C, Has the highest hardness used for ball bearings,
races; high strength; is usually considered a more desirable
choice in knife-making than 440A except for diving or
other salt-water applications. |
| 446 |
High corrosion and scaling resistance at high temperatures.
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| 500 Series - Heat-Resisting Chromium
Alloys |
| 501 |
This stainless steel is heat resistant with good mechanical
properties, typically used in heat exchangers and oil refinery
equipment. |
| 502 |
This stainless steel is similar to 501 but with more ductility
and less strength. |
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| Standard mill finishes can be applied to flat rolled stainless
steel directly by the rollers and by mechanical abrasives. Steel
is first rolled to size and thickness and then annealed to change
the properties of the final material. Any oxidation that forms
on the surface (scale) is removed by pickling, and the passivation
layer is created on the surface. A final finish can then be
applied to achieve the desired aesthetic appearance.
No. |
Description |
| 0 |
Hot rolled, annealed, thicker plates |
| 1 |
Hot rolled, annealed and passivated |
| 2D |
Cold rolled, annealed, pickled and passivated |
| 2B |
Cold rolled, annealed, pickled and passivated with additional
pass-through polished |
| 2BA |
Bright annealed (BA) same as above with highly polished
rollers |
| 3 |
Coarse abrasive finish applied mechanically (Grit range
is usually specified) |
| 4 |
Brushed finish (Grit range is usually specified) |
| 5 |
Satin finish |
| 6 |
Matte finish |
| 7 |
Reflective finish |
| 8 |
Mirror finish |
| 9 |
Bead blast finish |
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