55SiMnVB

Alloy Steel

55SiMnVB / A77552

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

Chemical Composition (%)

C0.52
SI0.7
MN1
P0.035
S0.035
CR0.35
NI0.35
CU0.25

Available Forms

Bar, Plate, Tube, Forging, Wire

Uses

Low-alloy engineering steel with enhanced hardenability and strength from alloying elements. Chromium (≈0.35%) improves hardenability, wear and corrosion resistance. Nickel (≈0.35%) 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 760–820 °C and quench (oil/water) then temper at 150–400 °C for high hardness; spheroidize anneal (680–720 °C) improves machinability of the as-rolled bar.

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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