1.What is AISI 4140 Steel?
AISI 4140 alloy steel round bar sheet plate belongs to medium hardenability steel.AISI 4140 steel has high fatigue strength and low notch sensitivity. Low-temperature impact toughness is also very high, no obvious temper brittleness. AISI 4140 steel round bar is mainly used after quenching and tempering state. it is used to manufacture high-strength parts under impact loads and the fittings with large cross-sections and other stressed members. Such as the horizontal eccentric shaft of the horizontal forging machine, the crankshaft of the forging press, and etc.
Its equivalent grade is JIS SCM440 and DIN 1.7225. The properties and composition of 4140 steel round bar sheet plate as below.

2.4140 Steel Grade Equivalent 
China GB steel number 42CrMo, Germany DIN steel number 42CrMo4, Germany DIN material number 1.7225, French NF standard 40CD4/42CD4, Japanese JIS standard SCM440, British BS standard 708M40/708A42/709M40, American AISI/ASTM 4140, American SAE 4140, American UNS Standard G41400
(4140 alloy structural steel, executive standard: ASTM A29/A29M-04)

3.4140 Steel Chemical Composition
C:0.38-0.45 Si:0.17-0.37 S：≤0.035 P:≤0.035
Mn:0.50-0.80 Cr:0.90-1.20 Mo:0.15-0.25 Ni:≤0.30
Cu≤0.30

4. 1.7225 Steel Mechanical Properties
Mechanical properties:
Tensile strength σb (MPa): ≥1080(110)
Yield strength σs (MPa): ≥930(95)
Elongation δ5 (%): ≥12
Area shrinkage ψ (%): ≥45
Impact energy Akv (J): ≥63
Impact toughness value αkv (J/cm2): ≥78(8)
Hardness: ≤217HB
Sample size: sample blank size is 25mm

5.4140 Steel Photo

6.4140 Steel Test
How is SAE 4140 steel tested?
Our AISI 4140 steel round bar and steel plate composition detection is carried out by a spectrometer, which is fast, accurate and efficient in detection; hardness is tested by a hardness tester,
The hardness tester is based on the Leeb hardness measurement principle, which can easily and quickly measure a variety of metal materials. While displaying the hardness measurement value immediately, it can be freely converted between different hardness scales, and the tolerance limit can be set in advance, and it will automatically alarm when it exceeds the range.
1. Measuring range: (170-960)HLD,(17-68.5)HRC,(19-651)HB,(80-976)HV,(30-100)HS,(59-85)HRA(13-100 )HRB
2. Measurement direction: support 360° (vertical down, oblique down, horizontal, oblique up, vertical up)
3. Hardness scale: Richter (HL), Brinell (HB), Rockwell B (HRB), Rockwell C (HRC), Rockwell A (HRA), Vickers (HV), Shore (HS)
4. Display: quarter dot matrix LCD
5. Data storage: maximum 500 groups (impact times 32 to 1)
6. Working voltage: 3V (2 AA size alkaline batteries connected in series)
7. Continuous working time: about 100 hours (when the backlight is not turned on)

We have been specializing in the production of 4140 alloy steel for decades, providing 4140/1.7225/SCM440 alloy round bar, square and flat steel, etc. We have our own cutting and processing facilities, rich production experience, and the specifications can be customized according to your needs Requires tailoring and customization. Over the years, we have been focusing on special steel dealers and suppliers with high-quality booths. As a professional AISI 4140 steel supplier, you are welcome to inquire at any time.

Songshun specialized in Special Steel for almost 20 years. We can supply mold steel, high speed steel, alloy steel, free cutting steel and etc.Welcome your contact 24 hours a day!!!