3440
Alloy Steel3440
AISI/SAE 3440 carbon / alloy steel.
Chemical Composition (%)
| C | 0.4 |
|---|---|
| NI | 2.75 |
| CR | 0 |
| P | 0.03 |
| S | 0.03 |
Applications
International high-end steel grade for aerospace, oil & gas, defense or engineering machinery.
Available Forms
Bar, plate, sheet, tube, forgings, strip, wire, powder
Uses
Low-alloy engineering steel with enhanced hardenability and strength from alloying elements. Chromium (≈0.45%) improves hardenability, wear and corrosion resistance. Nickel (≈3.125%) increases toughness and impact strength at low temperature. Applied to gears, shafts, bolts, connecting rods, pressure parts and heavy forgings in automotive, energy and machinery sectors.
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.
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).
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