Chemical Composition
|
Standard
|
Grade
|
C
|
Mn
|
P
|
S
|
Si
|
Ni
|
Cr
|
Mo
|
|
ASTM
A29
|
4140
|
0.38-0.43
|
0.75-1.00
|
0.035
|
0.040
|
0.15-0.35
|
–
|
0.8-1.10
|
0.15-0.25
|
|
EN
10250
|
42CrMo4/
1.7225
|
0.38-0.45
|
0.6-0.9
|
0.035
|
0.035
|
0.4
|
–
|
0.9-1.2
|
0.15-0.30
|
|
JIS
G4105
|
SCM440
|
0.38-0.43
|
0.60-0.85
|
0.03
|
0.03
|
0.15-0.35
|
–
|
0.9-1.2
|
0.15-0.30
|
Mechanical
Properties
|
Properties
|
Metric
|
Imperial
|
|
Tensile
strength
|
655 MPa
|
95000
psi
|
|
Yield
strength
|
415 MPa
|
60200
psi
|
|
Bulk
modulus (typical for steel)
|
140 GPa
|
20300
ksi
|
|
Shear
modulus (typical for steel)
|
80 GPa
|
11600
ksi
|
|
Elastic
modulus
|
190-210
GPa
|
27557-30458
ksi
|
|
Poisson’s
ratio
|
0.27-0.30
|
0.27-0.30
|
|
Elongation
at break (in 50 mm)
|
25.70%
|
25.70%
|
|
Hardness,
Brinell
|
197
|
197
|
|
Hardness,
Knoop (converted from Brinell hardness)
|
219
|
219
|
|
Hardness,
Rockwell B (converted from Brinell hardness)
|
92
|
92
|
|
Hardness,
Rockwell C (converted from Brinell hardness. Value below normal HRC range,
for comparison purposes only)
|
13
|
13
|
|
Hardness,
Vickers (converted from Brinell hardness)
|
207
|
207
|
|
Machinability
(based on AISI 1212 as 100 machinability)
|
65
|
65
|
Forging
Preheat the steel carefully,
heat to 1150 °C – 1200 °C maximum, hold until temperature is uniform throughout
the section.
Do not forge below 850 °C. Following the forging operation, the work piece should be cooled
as slowly as possible.
Heat
Treatment
- Annealing:
Heat
AISI 4140
steels to 800 °C –
850 °C, hold until temperature is
uniform throughout the section and cool in furnace.
- Normalizing:
Heat
steel alloy 4140 to 870 °C –
900 °C, hold until temperature is
uniform throughout the section, soak for 10 – 15 minutes and cool in still
air.
- Tempering: Re-heat 4140
grade steel to 550 °C
– 700 °C
as required, hold until temperature is uniform throughout the section,
soak for 1 hour per 25 mm of section, and cool in still air.
Hardening
AISI alloy 4140 steel bar, plate
and square can be hardened by cold working, or heating and quenching.
AISI 4140 alloy steel is usually supplied ready heat treated to hardness in 18-22 HRC. If further heat treatment
is required, then heat to 840 °C – 875 °C, hold until temperature is
uniform throughout the section, soak for 10 – 15 minutes per 25 mm section, and
quench in oil, water, or polymer as required.
Applications
AISI alloy 4140 steel bar, flat or plate material can be used for as
wide variety of applications where greater toughness and wear resistance is
needed over lower carbon grades. Typical applications for 4140 tool steel include adapters, arbors,strippers, mold bases, ejectors, back
up and support tooling, fixtures, jigs, molds, cams, drill collars, axle
shafts, bolts, crankshafts, stubs, couplings, reamer bodies, axles, shafting,
piston rods, rams, hydraulic machinery shafts, gears, gear racks, chain links,
spindles, tool bodies, tool holders, tie rods, connection rods, chuck bodies,
conveyor pins & rolls, ejector pins, forks, gears, guide rods, hydraulic
shafts & parts,lathe spindles, logging parts, milling spindles, motor shafts,
nuts, pinch bars, pinions, pump shafts,boring bars,tracks, slides, wear strips
or parts, forming dies, brake dies, trim dies, bolsters, machinery parts and
components, etc.
