We manufacture forging ingots, billets, and blooms in alloy steel specifically for SCM420H, tailored for high-performance engineering and case hardening applications. SCM420H is a low carbon chromium-molybdenum alloy steel designed with controlled hardenability, making it ideal for components requiring uniform heat treatment response and consistent mechanical properties.
The “h” designation indicates controlled hardenability limits, ensuring predictable hardness distribution during quenching and tempering. Chromium enhances hardenability and wear resistance, while molybdenum improves fatigue strength and resistance to temper brittleness. SCM420H provides excellent machinability in the annealed condition and superior performance after carburizing, making it highly suitable for automotive and precision engineering applications.
This steel provides an excellent balance of surface hardness, core toughness, and process consistency.
| Element | Content (%) | Function / effect |
| Carbon (c) | 0.18 - 0.23 | Provides core toughness and supports carburizing |
| Manganese (Mn) | 0.60 - 0.85 | Improves hardenability and strength |
| Silicon (si) | 0.15 - 0.35 | Improves strength and elasticity |
| Chromium (cr) | 0.90 - 1.20 | Enhances hardenability and wear resistance |
| Molybdenum (mo) | 0.15 - 0.30 | Improves fatigue resistance and temperature stability |
| Phosphorus (p) | Max 0.030 | Impurity; lower content improves toughness |
| Sulphur (s) | Max 0.030 | Impurity; controlled content improves machinability |
(Properties may vary depending on section size and heat treatment conditions)
Controlled hardenability in SCM420H ensures consistent heat treatment performance across different section sizes.
SCM420H has several international near equivalents, including:
SCM420H is specially developed for applications requiring consistent heat treatment results and uniform mechanical properties. Its controlled hardenability ensures reliable performance, reduces distortion during heat treatment, and improves product quality. Additionally, its excellent carburizing response provides long service life and high wear resistance.
| Grade | Carbon (%) | Key applications | Heat treatment | Comments |
| SCM420H | 0.18 - 0.23 | Gears, shafts, automotive parts | Carburizing, quenching & tempering | Controlled hardenability steel |
| 20CrMo4H | 0.17 - 0.24 | Automotive and engineering components | Carburizing | European equivalent |
| AISI 4120H | 0.18 - 0.23 | Transmission and machinery parts | Carburizing | American equivalent |
| DIN 1.7243H | 0.18 - 0.23 | Precision engineering components | Carburizing | German equivalent |
SCM420H is a high-quality chromium-molybdenum carburizing alloy steel designed for case hardening applications where controlled hardenability is required. It provides excellent surface hardness, core toughness, and reliable performance for automotive and engineering components.