40Cr

Alloy Steel

40Cr

General-purpose Cr Q&T steel. (GB/T 3077; equiv GB 40Cr / DIN 41Cr4 / JIS SCr440). Nominal values—confirm mill certificate.

Chemical Composition (%)

C0.37
SI0.17
MN0.5
CR0.8
P0.035
S0.035

Mechanical Properties

Tensile:≥980 MPa;Yield:≥785 MPa;Elong:≥9%;RA:≥45%;Akv:≥47 J

Chinese Standard

T 3077 40Cr

Equivalent Grades

GB 40Cr / DIN 41Cr4 / JIS SCr440

Applications

通用调质铬钢。,"Bar

Available Forms

Forging"

Uses

Low-alloy engineering steel with enhanced hardenability and strength from alloying elements. Chromium (≈0.95%) improves hardenability, wear and corrosion resistance. 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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