55SiCr

Alloy Steel

55SiCr / A21553

55SiCr grade supplied by Shanxi Youte Steel (jlhsteel.net).

Chemical Composition (%)

C0.51
SI1.2
MN0.5
P0.025
S0.02
CR0.5
NI0.35
CU0.25

Available Forms

Bar, Plate, Tube, Forging, Wire

Uses

Spring steel with high elastic limit and fatigue strength for coils, leaf springs, clips and suspension parts. Silicon (≈1.4%) 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.

Comments 0