24 July 2021 Structural Steel Bar
40CrNiMoA Structural Steel Bar
40CrNiMoA alloy structural steel is made of high-quality carbon structural steel by adding one or several alloying elements (total content not exceeding 5%). Common quality defects of bearing parts after heat treatment include: quenching microstructure overheating, underheating, quenching cracks, insufficient hardness, heat treatment deformation, surface decarburization, soft spots, etc. 40CrNiMoA structural steel is mainly used to make more important quenched and tempered parts that require high strength, high toughness, large cross-sectional size, such as the transmission eccentric shaft of the horizontal forging machine, and the crankshaft of the forging press. After quenching and tempering, it is used to make important parts that require good plasticity, high strength and large size. In heavy machinery, high-load shafts, steam turbine shafts, blades with a diameter greater than 250mm, high-load transmission parts, fasteners, crankshafts, gears, etc. In addition, it can also be used to make important parts with special performance requirements after nitriding treatment.
Chemical Composition:
| C(％) | Si(％) | Mn(％) | P(％) | S(％) | Cr(％) | Ni(％) | Cu(％) | Mo(％) |
|---|---|---|---|---|---|---|---|---|
| 0.37～0.4 | 0.17 ~ 0.37 | 0.50 ~ 0.80 | ≤0.025 | ≤0.025 | 0.60～0.90 | 1.25 ~ 1.65 | ≤0.25 | 0.15 ~ 0.25 |
Mechanical Propoerties:
| Yield Strength Rp0.2(MPa) | Tensile Strength Rm(MPa) | Impact Energy AKV(J) | Elongation A(%) | Impact toughness | Reduction of area ψ (%): | Hardness |
|---|---|---|---|---|---|---|
| ≥ 835(85) | ≥ 980(100) | ≥ 78 | ≥ 12 | ≥ 98(10) | ≥ 55 | ≤ 269 HBW |
Equivalent Grade:
Germany: 34CrNiMo6
United States: 4340
Japan: SNCM439 (SNCM8)
United Kingdom: 817M40
Italy: 40NiCrMo7