32CrAlMo7
Alloy Steel32CrAlMo7
Nitriding steel.
Chemical Composition (%)
| C | 0.28 |
|---|---|
| SI | 0.15 |
| MN | 0.5 |
| CR | 1.5 |
| MO | 0.15 |
| AL | 0.8 |
| P | 0.025 |
| S | 0.03 |
Applications
High-end / niche grade used in aerospace, defense, tooling, bearing, gear or heavy shaft applications.
Available Forms
Bar, plate, sheet, tube, forgings, strip, wire, powder
Uses
Nitriding steel that develops an extremely hard, wear- and corrosion-resistant surface after nitriding with minimal distortion. Aluminium (≈0.95%) forms hard AlN nitrides, giving the highest surface hardness. Used for crankshafts, cylinder liners, screws, valves, die blocks and precision machine components.
Heat Treatment
Austenitize at 820–870 °C (oil or water quench depending on section) and temper at 400–650 °C to the required strength/toughness balance. Quench & temper first to ≈30–40 HRC, then gas/nitride at 480–540 °C for 10–60 h; no further quench needed — minimal distortion.
Precautions
Preheat and control interpass temperature when welding; post-weld heat treatment or stress relief is recommended to avoid hard-zone cracking. Use low-hydrogen electrodes. Protect from decarburization during heating (controlled atmosphere or protective coating). Machine the core stock before surface hardening; leave grinding allowance for the hardened case.
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