4130
Chromium-Molybdenum Steel
| 4130
(Chromoly) Normalized Alloy Steel |
| Minimum Properties |
Ultimate
Tensile Strength, psi |
97,200 |
| Yield
Strength, psi |
63,100 |
| Elongation |
25.5% |
| Rockwell
Hardness |
B92 |
| |
| 4130
(Chromoly) Annealed Alloy Steel |
| Minimum Properties |
Tensile
Strength, psi |
81,200 |
| Yield
Strength, psi |
52,200 |
| Elongation |
28.2% |
| Rockwell
Hardness |
B82 |
| Chemistry |
Iron
(Fe) |
97.3
- 98.22% |
| Carbon
(C) |
0.28
- 0.33% |
| Chromium
(Cr) |
0.8
- 1.1% |
| Manganese
(Mn) |
0.4
- 0.6% |
| Molybdenum
(Mo) |
0.15
- 0.25% |
| Phosphorus
(P) |
0.035%
max |
| Sulphur
(S) |
0.04%
max |
| Silicon
(Si) |
0.15
- 0.35% |
| Principal
Features |
AISI
4130 is a low alloy steel containing
molybdenum and chromium as strengthening agents. The carbon content is
nominally 0.30% and with this relatively low carbon content the alloy
is excellent from the fusion weldability standpoint. The alloy can be
hardened by heat treatment. |
|
| Applications
|
Typical applications for 4130
low alloy steel
include. structural use such as aircraft engine mounts and welded
tubing applications. |
|
| Machinability
|
This alloy is readily
machined by conventional
methods. Machinability is best with the alloy in the normalized and
tempered condition. Although the alloy may be machined in the fully
heat treated condition, machinability becomes more difficult with
increasing strength (hardness) of the alloy. |
|
| Forming |
Formability is best in the
annealed condition for
which the ductility is very good, Bend radii of 1t on annealed sheet
material may be made.
|
| Welding |
4130 alloy is noted for its
weldability by all of
the commercial methods.
|
| Heat Treatment
|
Heating at 1600 F followed by
an oil quench will
harden the 4130 alloy. For best results a normalizing pre-hardening
heat treatment may be used at 1650 to 1700 F followed by the 1600 F
soak and oil quench.
|
| Forging |
Forge at 2200 F maximum down
to 1750 F.
|
| Hot Working
|
4130 in the annealed
condition has excellent
ductility. Thus it is usually not necessary to do hot working to form
parts. If hot working is needed it can be done in the range of 2000 F
to 1500 F.
|
| Cold Working
|
Cold working by conventional
methods is readily
accomplished on this alloy.
|
| Annealing |
4130 (and most of the other
low alloy steels) may
be annealed at 1550 F for a time long enough to allow thorough heating
of the section size. It should then be cooled in the furnace at a rate
of less than 50 F per hour down to 900 F, followed by air cooling from
900 F.
|
| Aging |
Not applicable to this alloy.
|
| Tempering |
Tempering is done to restore
some of the ductility
that may be lost after the hardening heat treatment and quench. Alloy
4130 is tempered at between 750 F and 1050 F, depending upon the
strength level desired. The lower the tempering temperature the greater
the strength.
|
| Hardening |
Hardening is accomplished by
heat treatment or by
cold working -- see "Heat Treatment".
|
| Other Comments
|
The 4130 alloy is a through
hardening alloy and
should not be case hardened. |
|
Physical Properties:
 |
| Density (lb / cu.
in.) |
0.283 |
| Specific Gravity |
7.8 |
| Specific Heat
(Btu/lb/Deg F - [32-212 Deg F]) |
0.114 |
| Melting Point (Deg
F) |
2610 |
| Thermal
Conductivity |
22.3 |
| Mean Coeff Thermal
Expansion |
7 |
| Modulus of
Elasticity Tension |
29 |
|
