What is AISI 4130?
1.AISI 4130 steel manufacturer and exporter, providing round, square, flat, block and shaft etc. AISI 4130 steel is defined as a low alloy steel containing 1% Cr and 0.2% Mo as strengthening alloying elements. It provides good strength, toughness, corrosion resistance and machinability. Compared with AISI 4140, the carbon content is lower, 0.28-0.33%, so it is easy to weld. AISI 4130 is usually provided in the hardened and tempered condition with a hardness range of 207-235HB.
2.Chemical composition
| Standard | Grade | C (%) | Si (%) | Mn (%) | P (%) | S (%) | Cr (%) | Mo (%) |
|---|---|---|---|---|---|---|---|---|
| EN10083 | 25CrMo4 (1.7218) | 0.22-0.29 | ≤0.40 | 0.60-0.90 | ≤0.025 | ≤0.035 | 0.90-1.20 | 0.15-0.30 |
| ASTM A29 | 4130 | 0.28-0.33 | 0.15-0.35 | 0.40-0.60 | ≤0.035 | ≤0.040 | 0.80-1.10 | 0.15-0.25 |
| JIS G4105 | SCM430 | 0.28-0.33 | 0.15-0.35 | 0.60-0.85 | ≤0.035 | ≤0.040 | 0.90-1.20 | 0.15-0.30 |
| GB 3077 | 30CrMo | 0.26-0.34 | 0.17-0.37 | 0.40-0.70 | ≤0.035 | ≤0.035 | 0.80-1.10 | 0.15-0.25 |
3.Physical properties
| Property | Value |
|---|---|
| Density (g/cm³) | 7.85 |
| Melting Point (°C) | 1432 |
| Poisson's Ratio | 0.27-0.30 |
| Machinability (AISI 1212 as 100%) | 70% |
| Specific Gravity | 7.8 |
| Thermal Conductivity (W/(m·K)) | 46 |
| Modulus of Elasticity in Tension (GPa) | 29 |
4.Mechanical properties
| Grade | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) | Hardness (HBW) | Impact Charpy-V, -18°C (J) |
|---|---|---|---|---|---|
| 60K | ≥ 586 | ≥ 414 | ≥ 18 | 174-237 | ≥ 42 |
| 75K | ≥ 655 | ≥ 517 | ≥ 17 | 197-235 | ≥ 42 |
5.Forging
The forging temperature of AISI 4130 steel should be carried out between 950℃-1200℃, the lower the forging end temperature, the finer the grain. Keep the steel for uneven heating for a proper time before forging, but do not forge below 950℃. AISI 4130 steel should be cooled as slowly as possible after forging.
6. Normalization
Normalizing is used to refine the forging structure that may cool unevenly after forging, as a quenching and tempering treatment before the final heat treatment. The normalizing temperature of AISI 4130 steel should be between 880℃-900℃. Keep the appropriate time to heat the steel evenly and complete the transformation from ferrite to austenite. Cool in still air.
7. Annealing
AISI 4130 steel can be annealed after forging to eliminate stress and obtain a good structure suitable for machining. The annealing temperature should be between 800℃-850℃, and keep the appropriate time to heat the steel evenly. Cool slowly in the furnace.
8. Hardening
This heat treatment will obtain a martensitic structure after quenching, increase surface hardness and strength. AISI 4130 steel should be carried out between 870℃-890℃, keep the appropriate time to heat the steel fully, and then quench in oil, or water. Tempering should be performed immediately after quenching.
9. Tempering
Tempering is commonly used to relieve stress during hardening and to optimize hardness and mechanical properties. The actual tempering temperature will be selected based on the required performance. AISI 4130 is carefully heated to a suitable temperature, usually between 400°C-570°C, kept at this temperature for 2 hours per 25mm score, and then cooled in air. The lower the tempering temperature, the greater the strength. However, tempering between 250-375°C is not recommended, as tempering in this range will severely reduce the impact value.
10. Applications
AISI 4130 steel can be used as forgings in industries such as aerospace, oil and gas, automotive, agriculture and defense industries. Typical applications of 4130 steel include: forged valve bodies, pumps, aircraft engine brackets, welded pipes, fittings, hydraulic tools, etc.
