Its typical uses are axle shafts, crankshafts, connecting rods, gears, high tensile bolts and studs, propeller shafts joints, rifle barrels and breech mechanisms for small arms parts, introduction hardened trackpins.
Forgeability
Good
Heat Treatment Ability
Very Versatile
Machineability
Difficult
Weldability
Not recommended
Chemical Composition
Element
Min
Max
Carbon
0.36
0.44
Silicon
0.10
0.35
Manganese
0.70
1.00
Phosphorous
–
0.04
Sulphur
–
0.04
Chromium
0.90
1.20
Molybdenum
0.25
0.35
Mechanical Properties
Condition
R
S
T
U
V
Limited Ruling Section, mm
254
152
102
64
29
Tensile Strength, MPa min.
690/850
770/930
850/1000
930/1080
1000/1160
Yield Stress; MPa min.
480
570
665
740
835
Elongation, % min.
15
15
13
12
12
Izod Impact Value; Joule
34
54
54
47.5
47.5
Brinnel Hardness Number
201/255
223/277
248/302
269/331
293/352
Foreign Equivalent Specifications
Standard German Mat. No.
Din
SAE
AISI
JIS
1.7225
GS-42rM04
4140H
4140H
G4042Type: SCM4H
Stock Size Range
(Round Black Bar)
20
2.466 kg/m
80
39.458 kg/m
25
3.853 kg/m
85
44.545 kg/m
30
5.549 kg/m
90
49.939 kg/m
35
7.553 kg/m
95
55.642 kg/m
40
9.865 kg/m
100
61.654 kg/m
45
12.485 kg/m
110
74.536 kg/m
50
15.413 kg/m
115
81.537 kg/m
55
18.650 kg/m
120
88.781 kg/m
60
22.195 kg/m
130
104.195 kg/m
65
26.049 kg/m
140
120.841 kg/m
70
30.210 kg/m
150
138.721 kg/m
75
34.680 kg/m
160
157.833 kg/m
Larger sizes and forgings are also available and please
remember to allow for surface removal of + 6% to ensure cleanup.
