Chemical composition
material
C
Si
Mn
P
S
Cr
Ni
Mo
Cu
35CrMoA
0.34-0.39
0.17-0.37
0.40-0.70
0.015
max
0.010
max
0.80-1.10
0.30
max
0.15-0.25
0.25max
42CrMoA
0.39-0.45
0.17-0.37
0.50-0.80
0.015
max
0.010
max
0.90-1.20
0.20
max
0.20-0.25
0.25max
Equivalent Steel Grade
DIN
ASTM A29
JIS G4105
BS
GB
EN ISO 10250
1.7225
4140
SCM440
708M40/708A42/709M40
42CrMo
42CrMo4
Mechanical Properties
Grade
Tensile Strength
Mpa
Yield Strength
Mpa
Elongation %
Reduction %
-40℃Akv2/J
Hardness
10.9
≥1040
≥940
≥9
≥48
≥50
HRC32-39
8.8
≥830
≥660
≥12
≥52
≥70
HRC23-34
Surface Treatment Bar: Origin Black, Origin Annealing bright, Turned, Peeled, Grinded
Heat Treatment/ Anealing 1) Forging Preheat the steel carefully, then raise the temperature to 1150-1200°C for forging. Do not forge below 850°C. 2)Annealing Heat the AISI 4140 slowly to 800-850°C and allow enough time for the steel to be thoroughly heated. Cool slowly in the furnace to 480°C followed by air cooling. 3)Stress Relieving When parts are heavily machined, ground or otherwise subject to cold work, stress relieving will be beneficial prior to hardening. 4)Hardening AISI 4140 steel is usually supplied ready heat treated to 18-22HRC. If further heat treatment is required annealed AISI 4140 should be heated slowly to 840-875°C and after adequate soaking at this temperature quench in oil. Temper as soon as the tools reach room temperature. 5)Tempering Heat the AISI 4140 carefully to a suitable temperature selected by reference to a tempering chart or table (usually between 550-700°C, soak at the temperature for 2 hours per 25mm of ruling section, then allow to cool in air. Tempering between 250-375°C is not advised as tempering within this range will seriously reduce the impact value.
Quality :
Our products will be from black round bar. We will order the raw material from first class steel making companies to guarantee the inner quality. You can also lock the raw material manufacturer for your order.
We will continually improves and expands the quantity and quality of our product which exactly meet customers need. We do whatever it takes to make our clients happy. We will develop long-term commercial and technical partnerships with customers. And we are committed to continual quality improvement of all internal processes. The success of our quality program is affirmed by our strong customer retention rate.
Certification :
Achieving the ISO 9001:2008 Certification is just one example of our Products’ dedication to quality and continuous improvement. Each employee is responsible for understanding company expectations and adhering to the procedures of our Quality Management System. Our Products ensures customers receive the material ordered with accurate supporting paperwork. Customers can count on proper documentation, on-time performance and effective follow-up.
Our company
Our story Since beginning operation in 1996, We has been dedicated to providing more than just material supply, We has helped customers reduce costs and improve the bottom line. This approach to partnering with customers has made our Products a leader among Steel Round bar and one of the fastest growing companies in China.
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