4130

Alloy Steel

4130

Low-alloy Cr-Mo steel, aerospace tubing. (AISI/SAE; equiv GB 25CrMo4 / DIN 25CrMo4 / JIS SCM430 / GB 30CrMo). Nominal values—confirm mill certificate.

Chemical Composition (%)

C0.27
MN0.3
SI0.15
CR0.75
MO0.15
P0.035
S0.04

Mechanical Properties

Tensile:≥560 MPa;Yield:≥460 MPa;Elong:≥21%

Equivalent Grades

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).

Applications

低合金铬钼钢，航空管材。,"Bar

Available Forms

Tube

Uses

Plate"

Heat Treatment

Low-alloy engineering steel with enhanced hardenability and strength from alloying elements. Chromium (≈0.975%) improves hardenability, wear and corrosion resistance. Molybdenum (≈0.2%) raises high-temperature strength and prevents temper embrittlement. Applied to gears, shafts, bolts, connecting rods, pressure parts and heavy forgings in automotive, energy and machinery sectors.

Precautions

Austenitize at 820–870 °C (oil or water quench depending on section) and temper at 400–650 °C to the required strength/toughness balance.

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