24 July 2021 Structural Steel Bar
SAE 4130 Structural Steel Bar
SAE 4130 alloy structural steel belong to ASTM A29/A29M-04 standard grade, this kind of steel is usually used in quenched and tempered state, when the carbon content is lower, it can also be used as carburizing steel that requires higher core strength. It has high strength and toughness, high hardenability, and the critical hardening diameter in oil is 15～70mm; the thermal strength of steel is also good, and it has sufficient high temperature strength below 500℃, but its strength is significant at 550℃ decline.
SAE 4130 steel is a commonly used alloy steel for many projects, and this article will briefly investigate its properties. By outlining its makeup, strengths, and uses, this article may help readers decide if 4130 steel fits their specific job. We will first explore the physical properties of 4130 steel, followed by its mechanical properties and finally its applications, to show where this steel shines.
SAE 4130 steel equivalent grade and chemical composition:
| Standard | Grade | C | Mn | P | S | Si | Cr | Mo |
|---|---|---|---|---|---|---|---|---|
| ASTM A29 | 4130 | 0.28-0.33 | 0.40-0.60 | 0.035 | 0.040 | 0.15-0.35 | 0.80-1.10 | 0.15-0.25 |
| EN10250 /EN10083 | 25CrMo4/ 1.7218 | 0.22-0.29 | 0.60-0.90 | 0.025 | 0.035 | ≦0.40 | 0.90-1.2 | 0.15-0.30 |
| JIS G4105 | SCM430/ SCM2 | 0.28-0.33 | 0.60-0.85 | 0.030 | 0.030 | 0.15-0.35 | 0.90-1.2 | 0.15-0.30 |
Mechanical Properties:
| Tensile strength, ultimate | 560 MPa |
|---|---|
| Tensile strength, yield | 460 MPa |
| Modulus of elasticity | 190-210 GPa |
| Bulk modulus (Typical for steel) | 140 GPa |
| Shear modulus (Typical for steel) | 80 GPa |
| Poissons ratio | 0.27-0.30 |
| Elongation at break (in 50 mm) | 21.50% |
| Reduction of area | 59.6 |
| Hardness, Brinell | 217 |
| Hardness, Knoop (Converted from Brinell hardness) | 240 |
| Hardness, Rockwell B (Converted from Brinell hardness) | 95 |
| Hardness, Rockwell C (Converted from Brinell hardness) | 17 |
| Hardness, Vickers (Converted from Brinell hardness) | 228 |
| Machinability (Annealed and cold drawn.) | 70 |
Forging:
SAE 4130 steel should be forged between 1230 and 950 º C (2250 and 1750 º F). The lower the finishing temperature from forging, the finer will be the grain size. If the 4130 alloy steel is forged at too low a temperature, there is a risk of the formation of a non-uniform structure in certain areas of the forged part, necessitating a normalizing treatment, prior to further heat treatment.
Fabrication and Heat Treatment
Machinability - SAE 4130 steel can be easily machined using conventional methods. However, machining becomes difficult when the hardness of the steel is increased.
Forming of SAE 4130 steel can be performed in the annealed condition.
- Welding of SAE 4130 steel can be performed by all commercial methods.
- Heat Treatment - SAE steel is heated at 871°C (1600°F) and then quenched in oil. This steel is usually heat-treated at temperatures ranging from 899 to 927°C (1650 to 1700°F).
- Forging of SAE 4130 steel can be performed at 954 to 1204°C (1750 to 2200°F).
- Hot working of SAE 4130 steel can be done at 816 to 1093°C (1500 to 2000°F).
- SAE 4130 steel can be cold worked using conventional methods.
- SAE 4130 steel can be annealed at 843°C (1550°F) followed by air cooling at 482°C (900°F).
- Tempering of SAE 4130 steel can be performed at 399 to 566°C (750 to 1050°F), depending on the desired strength level.
- Hardening of SAE 4130 steel can be done with cold working or heat treatment.
Applications:
SAE 4130 steel is an exceptionally tough metal suitable for manufacturing, welding, cutting, and other high-stress applications in industry. It has great heat treatment characteristics impart a high toughness and, combined with its great workability and machinability. Though most often implemented as structural steel can be with applications such as:
- Manufacturing equipment for bearings, vehicle parts, and gears
- Rock crushing machinery
- Resistance welding products
- Drill bits and taps
- Mills and cutters