3A21

Other

3A21 / (LF21)

3A21 grade supplied by Shanxi Youte Steel (jlhsteel.net).

Chemical Composition (%)

FE0.7
SI0.6
MN1
CU0.2
TI0.15
MG0.05

Available Forms

Bar, Plate, Tube, Forging

Uses

Low-alloy engineering steel with enhanced hardenability and strength from alloying elements. 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

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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