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SPECIFICATION
DATA
SHEET:
440 Stainless
Steel
| BAR
|
TUBE
|
PIPE
|
| PSQ
SHAFT |
WELDING
ROD |
CASTINGS
|
| FORGINGS
|
PLATE
|
FLANGES |
| TG&P
SHAFTS |
SHEET
|
FITTINGS |
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Type
440A, 440B, and 440C
 | Hardenable
high-carbon chromium steels designed to provide stainless
properties with maximum hardness
| Have
maximum hardness together with high strength and corrosion
resistance in the hardened and stress relieved condition
| Always
used in the hardened or hardened and stress relieved
conditions
| None
of the alloys has its full corrosion resistance either in
the annealed or in the hardened and tempered condition
| Wide
applications where good corrosion resistance along with high
hardness or abrasion resistance is required |
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Available
Forms
Types
440A, 440B, and 440C Stainless Steels are available in:
|
Specifications
The
following specifications are generally applicable:
In
addition, Type 440 A is covered by spec AMS 5631 and Type 440C
is covered by spec AMS 5630C.
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Composition
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Property
|
Type
440A
|
Type
440B
|
Type
440C
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Carbon
|
.60
- .75
|
.75
- .95
|
.95
- 1.2
|
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Manganese
|
1.00
max
|
1.00
max
|
1.25
max
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Silicon
|
1.00
max
|
1.00
max
|
1.00
max
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Phosporus
|
.04
max
|
.04
max
|
.04
max
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Sulfur
|
.03
max
|
.03
max
|
.04
max
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Chromium
|
16.0
- 18.0
|
16.0
- 18.0
|
16.5
- 18.0
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Molybdenum
|
.75
max
|
.75
max
|
.75
max
|
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Nickel
|
.50
max
|
NA
|
NA
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Mechanical
Properties
|
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Type
440A
|
Type
440B
|
Type
440C
|
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Property
|
Annealed
|
Hardened
& Stress Relieved
|
Annealed
|
Hardened
& Stress Relieved
|
Annealed
|
Hardened
& Stress Relieved
|
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Ultimate
tensile strength, psi
|
105,000
|
260,000
|
107,000
|
280,000
|
110,000
|
285,000
|
|
0.2%
Yield strength, psi
|
60,000
|
240,000
|
62,000
|
270,000
|
65,000
|
275,000
|
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Elongation,
% in 2”
|
20
|
5
|
18
|
3
|
14
|
2
|
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Reduction
of area, %
|
45
|
20
|
35
|
15
|
25
|
10
|
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Rockwell
hardness
|
B95
|
C51
|
B96
|
C55
|
B97
|
C57
|
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Impact
strength Izod V-Notch, ft-lbs
|
NA
|
3-6
|
NA
|
2-5
|
NA
|
1-5
|
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Typical
Applications
| Used
in numerous applications in areas where a very hard and
abrasion resistant stainless is called for
| Applications
include pivot pins, dental and surgical instruments, cutlery
valve parts, ball bearings, nozzles, hardened steel balls
and seats for oil well pumps, plus valve parts |
|
Machinability
Because
of the high carbon content, these alloys have an abrasive action
on cutting tools. In the annealed condition, their machinability
rating is about 40% compared to Bessemer oven stock (AISI
B1112). As heat treated, the 440 series are difficult to
machine because of their high hardness. For parts that
require extensive machining, the free-machining versions, Type
440F or Type 440F Se, offer improved machining properties.
Formability
If
annealed for maximum softness, Types 440A, 440B, and 440C
Stainless Steels can be moderately cold formed with only
slightly more difficulty than the lower carbon, lower chromium
grades of stainless steel. They can also be hot headed.
Preheating in the range of 1400 - 1500° F insures the best
results in hot working. As these steels are strongly
air-hardening, all parts should be furnace cooled after hot
working to prevent cracking.
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Corrosion
Resistance
These
stainless steels have good corrosion resistance in the hardened
and stress relieved conditions. Hence, they should,
usually, be used only in that condition. These steels are
resistant to such conditions as fresh water, steam, crude oil,
gasoline, perspiration, and alcohol.
Heat
Treatment
PROCESS
ANNEAL: Heat at 1350-1450° F then cool very slowly in the
furnace.
FULL ANNEAL: Heat uniformly at 1550-1600° F soak and cool
slowly in furnace to 1000-1250° F at a rate of 20-50° F per
hour, then cool in air, oil, or water.
HARDENING: Preheat slowly to 1450° F and soak, then raise
temperature to 1850-1950° F, quench in warm oil or air.
Products hardness of C55-58 Rockwell.
STRESS RELIEVE: Heat to 300-800° F for 1 to 3 hours, air
cool.
Forgeability
When
forging, preheat to 1400-1500° F, then heat slowly and
uniformly to 1900-2150° F. Do not forge below 1700° F.
Weldability
Because
of their high hardenability, these steels are seldom welded.
However, satisfactory welds are possible by preheating parts to
500° F before welding, followed by a 6- to 8-hour anneal at
1350 - 1400° F and air cooling. When weld rods are required, a
composition similar to the parent metal should be used.
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