AISI 4140 Steel Round Bar Sheet Plate |JIS SCM440|DIN 1.7225

AISI 4140 Steel Catalog


Chemical Composition

Mechanical Properties / Physical Properties

Physical Properties

Heat Treatment

Quality Certificate Scaled




What is AISI 4140 Steel?

AISI 4140 alloy steel round bar sheet plate belongs to medium hardenability steel.AISI 4140 steel round bar has high fatigue strength and low notch sensitivity. Low-temperature impact toughness is also very high, no obvious temper brittleness. It 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.

  • AISI 4140 Steel Round Bar
  • sae aisi 4140
  • aisi 4140 steel test

Chemical Composition

The chemical composition of Song Shun AISI 4140 steel round bar.

Grade C (%) Si (%) Mn(%) P (%) S (%) Cr (%) Mo (%)
4140 0.38-0.45 0.17-0.37 0.50-0.80 ≤0.035 ≤0.035 0.90-1.20 0.15-0.25

Mechanical Properties/Physical Properties

The mechanical properties of AISI 4140 steel round bar

Properties Metric Imperial
Tensile strength >1080 MPa >156640 psi
Yield strength >930 MPa >134890 psi
Elongation at break >12% >12%
Reduction of area >45% >45%
Hardness ≤217HB ≤217HB

The physical properties of  1.7225 steel

Properties Metric Imperial
Density 7.85 g/cm³ 0.284 lb/in³
Melting point  1416°C  2580°F

Heat Treatment

SAE AISI 4140 steel heat treatment

In the annealed condition, the alloyed tool steel 1.7225 has good machinability

DIN 1.7225 steel has high ductility. It can be shaped in the annealed state using conventional techniques. More pressure or force is required to form because it is tougher than plain carbon steels.

Alloy steel 1.7225 can be welded with all advanced techniques. However, the mechanical properties will be affected if it is welded in the heat treated condition and post-weld heat treatment should be performed.

(4)Heat treatment
1.7225 tool steel is heated to 845°C (1550°F) and then oil quenched. Before hardening, it can be normalized by long heating to 913 °C (1675 °F) and then air cooling.

It is forged at 926 to 1205 °C

(6)Hot working
4140 steel can be hot worked at 816 to 1038 °C (1500 to 1900 °F).

(7)Cold working
1.7225 steel can be cold worked in the annealed condition using conventional methods.

Heat it to 800 – 850 °C, hold until the temperature is uniform throughout the section and cool in the kiln.

Heat the 1.7225 alloy steel to 870-900℃, hold until the temperature is uniform throughout the section, soak for 10-15 minutes, and cool in still air.

DIN 1.7225 steel can be tempered at 205 to 649 °C (400 to 1200 °F) depending on the desired hardness. The hardness of the steel can be increased if the tempering temperature is lower. For example, a tensile strength of 225 ksi can be achieved by annealing at 316 °C (600 °F), and a tensile strength of 130 ksi can be achieved by annealing at 538 °C (1000 °F).

Alloy steel according to DIN 1.7225 can be hardened by cold forming or heating and quenching.

Quality Certificate Scaled

AISI 4140 steel round bar quality certificate scaled

AISI 4140 steel round bar iso certify


What is the application of 4140 steel?

AISI 4140 steel round bar is an alloy structural steel with good strength and good comprehensive mechanical properties after heat treatment. It has good manufacturability. The maximum operating temperature is 427°C. It is used to manufacture forgings that require higher strength and larger quenched and tempered section than 35CrMo steel, and can also be used to manufacture turbine fasteners, tool bodies, dies, brake shoes, etc.

AISI 4140 steel round bar application


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)

  • AISI 4140 steel round bar Composition test spectrometer
  • AISI 4140 Steel Round Bar Hardness Test
  • AISI 4140 Steel Round Bar Test

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.