We manufacture forging ingots, billets, and blooms in boron-alloyed steel specifically for 20mncrb5, designed for case-hardened and heat-treated engineering applications requiring high surface hardness, excellent core toughness, and consistent hardenability. 20mncrb5 is a low carbon manganese-chromium boron steel that combines the benefits of case hardening with enhanced hardenability provided by boron addition. This grade is engineered to achieve a hard, wear-resistant surface with a tough and ductile core after carburizing, quenching, and tempering. The presence of manganese and chromium improves hardenability and wear resistance, while boron ensures uniform hardening even in thicker sections. 20mncrb5 is widely used in automotive and heavy engineering components where high fatigue strength and long service life are essential. This grade offers a cost-effective alternative to higher alloy case-hardening steels while maintaining excellent performance and reliability.
| Element | Content (%) | Function / effect |
| Carbon (c) | 0.17 – 0.23 | Provides core strength and case hardening response |
| Manganese (mn) | 1.00 – 1.30 | Improves hardenability and core toughness |
| Silicon (si) | 0.15 – 0.35 | Increases strength and elasticity |
| Chromium (cr) | 1.00 – 1.30 | Enhances wear resistance and hardenability |
| Boron (b) | 0.0005 – 0.003 | Significantly improves hardenability |
| Phosphorus (p) | Max 0.025 | Impurity; controlled to maintain toughness |
| Sulphur (s) | Max 0.025 | Impurity; controlled for machinability |
(Typical, depending on condition and heat treatment; properties may vary depending on case depth and heat treatment conditions)
The boron addition ensures consistent hardenability and uniform properties across section sizes.
20MnCrB5 has several international equivalents, including:
20mncrb5 is the ideal choice for case-hardened components requiring a hard, wear-resistant surface combined with a tough core. The boron addition ensures excellent hardenability, even in thicker sections, while maintaining cost efficiency and consistent performance in automotive and heavy engineering applications.
| Grade | Carbon (%) | Key applications | Heat treatment | Comments |
| 20mncrb5 | 0.17 – 0.23 | Gears, pinions, shafts | Carburizing + q&t | Boron-enhanced hardenability |
| 20mnCr5 | 0.17 – 0.23 | Transmission gears | Carburizing | No boron, lower hardenability |
| 16MnCr5 | 0.14 – 0.19 | Light-duty gears | Carburizing | Lower core strength |
20mncrb5 is a low carbon boron-alloyed case-hardening steel that offers high surface hardness, excellent core toughness, and superior fatigue resistance. It is a reliable and cost-effective material for gears and other highly stressed engineering components.