09MnNb
Alloy Steel09MnNb
Chinese GB steel 09MnNb for structural, container, bridge or machinery.
Chemical Composition (%)
| C | 0.02 |
|---|---|
| SI | 0.1 |
| MN | 0.2 |
| CR | 0 |
| NI | 0 |
| MO | 0 |
| P | 0.04 |
| S | 0.04 |
Applications
International high-end steel for aerospace, oil & gas, defense or engineering.
Available Forms
Bar, plate, sheet, tube, forgings, strip, wire, powder
Uses
Spring steel with high elastic limit and fatigue strength for coils, leaf springs, clips and suspension parts. Silicon (≈1.3%) raises elastic limit and tempering resistance. Supplied as strip, wire and bar; shot-peened after forming for longer service life.
Heat Treatment
Austenitize 830–880 °C (oil quench) and temper at 400–520 °C; stress-relieve formed springs at 230–320 °C after coiling.
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). Shot-peen after coiling to improve fatigue life; avoid sharp bends and surface defects.
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