27NCD5

Alloy Steel

27NCD5

French AFNOR Ni-Cr-Mo steel.

Chemical Composition (%)

C0.24
SI0.1
MN0.6
NI1.2
CR0.75
MO0.2
P0.025
S0.015

Applications

High-end / niche grade for aerospace, defense, tooling, bearing, gear or heavy shaft.

Available Forms

Bar, plate, sheet, tube, forgings, strip, wire, powder

Uses

Low-alloy engineering steel with enhanced hardenability and strength from alloying elements. Chromium (≈0.925%) improves hardenability, wear and corrosion resistance. Molybdenum (≈0.3%) raises high-temperature strength and prevents temper embrittlement. Nickel (≈1.4%) 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

Weldable with standard procedures; preheat may be needed for thick sections or higher-carbon/ alloy grades. Protect from decarburization during heating (controlled atmosphere or protective coating).

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