Guaranteed hardenable structural steel grades, with precise chemical composition and mechanical properties to ensure performance and quality. Below is a detailed table of various hardenable structural steels, including their chemical compositions, hardness, and heat treatment processes.
| Brand | Chemical Composition (mass fraction) (%) |
|-------------|-----------------------------------------|
| | C | Mn | Cr | Other |
| 45H | 0.42–0.50 | - | - | - |
| 20CrH | 0.17–0.23 | 0.70–1.10 | - | - |
| 40CrH | 0.37–0.44 | - | - | - |
| 45CrH | 0.42–0.49 | - | - | - |
| 40MnBH | 0.37–0.44 | 1.00–1.40 | - | B: 0.0005–0.0035 |
| 45MnBH | 0.42–0.49 | - | - | B: 0.0005–0.0035 |
| 20MnMoBH | 0.16–0.22 | 0.90–1.25 | - | B: 0.0005–0.0035; Mo: 0.20–0.30 |
| 20MnVBH | 0.17–0.23 | 1.05–1.45 | - | B: 0.0005–0.0035; V: 0.07–0.12 |
| 22MnVBH | 0.19–0.25 | 1.25–1.65 | - | B: 0.0005–0.0035; V: 0.07–0.12 |
| 20MnTiBH | 0.17–0.23 | 1.20–1.55 | - | B: 0.0005–0.0035; Ti: 0.04–0.10 |
| 20CrMnMoH | 0.17–0.23 | 0.85–1.20 | 1.05–1.40 | Mo: 0.20–0.30 |
| 20CrMnTiH | 0.17–0.23 | 0.80–1.15 | 1.00–1.35 | Ti: 0.04–0.10 |
| 20CrNi3H | 0.17–0.23 | 0.30–0.65 | 0.60–0.95 | Ni: 2.70–3.25 |
| 12Cr2Ni4H | 0.10–0.17 | 0.30–0.65 | 1.20–1.75 | Ni: 3.20–3.75 |
| 20CrNiMoH | 0.17–0.23 | 0.60–0.95 | 0.35–0.65 | Ni: 0.35–0.75; Mo: 0.15–0.25 |
**Notes:**
1. The silicon content for each grade ranges from 0.17% to 0.37%.
2. Residual element limits (mass fraction):
| Name | P | S | Cu | Cr | Ni |
|-----------------------|-------|-------|-------|-------|-------|
| High quality carbon | 0.040 | 0.040 | 0.25 | 0.25 | 0.25 |
| High quality alloy | 0.035 | 0.035 | 0.30 | 0.35 | 0.30 |
| Advanced high quality | 0.030 | 0.030 | 0.25 | 0.35 | 0.30 |
3. Copper content in hot-pressed steel should not exceed 0.20%.
**Hardness of steel in annealed or high temperature tempered state:**
| Brand | Indentation diameter DHB/mm ≥ | Brinell hardness HBS ≤ |
|--------------|-------------------------------|------------------------|
| 45H | 4.3 | 197 |
| 20CrH | 4.5 | 179 |
| 40CrH | 4.2 | 207 |
| 45CrH | 4.1 | 217 |
| 40MnBH | 4.2 | 207 |
| 45MnBH | 4.1 | 217 |
| 20MnVBH | 4.2 | 207 |
| 22MnVBH | 4.2 | 207 |
| 20MnTiBH | 4.4 | 187 |
| 20CrMnMoH | 4.1 | 217 |
| 20CrMnTiH | 4.1 | 217 |
| 20CrNi3H | 3.9 | 241 |
| 12Cr2Ni4H | 3.7 | 269 |
| 20CrNiMoH | 4.3 | 197 |
**Heat Treatment and Impact Toughness of Boron-Containing Steels:**
| Brand | Sample blank size /mm | Normalizing Temp /°C | Coolant | Quenching Temp /°C | Coolant | Tempering Temp /°C | Coolant | Impact toughness ak / (J/cm²) ≥ |
|--------------|------------------------|----------------------|---------|--------------------|---------|--------------------|---------|----------------------------------|
| 40MnBH | 25 | 880–900 | Air | 850±20 | Oil | 510±30 | Water | 69 |
| 45MnBH | 59 | - | - | - | - | - | - | 69 |
| 20MnMoBH | 15 | 930–950 | - | 880±10 | - | 200±20 | Air/water | 69 |
| 20MnVBH | 860±20 | - | - | 200±10 | - | - | - | 69 |
| 22MnVBH | - | - | - | 200±20 | - | - | - | 69 |
| 20MnTiBH | - | - | - | - | - | - | - | - |
These steels are suitable for machining parts and are similar to high-quality carbon and alloy structural steels. For more information, visit [Hardware Business Network Information Center](http://news.chinawj.com.cn).
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