MEDIUM-CARBON STEEL WITH ELEVATED CUTTING ABILITY Russian patent published in 2005 - IPC

FIELD: metal-working.

SUBSTANCE: invention relates to steel, used, for example, in manufacture of ball wrists, pull shaft tips, and spherical joints of car suspension by cold die forging methods. Medium-carbon steel according to invention contains following components, wt %: carbon 0.35-0.42, manganese 0.50-0.80, silicon 0.17-0.37, chromium 0.80-1.10, sulfur 0.020-0.040, vanadium 0.005-0.020, calcium 0.001-0.010, oxygen 0.001-0.015, iron and inevitable impurities - the rest. Oxygen-to-calcium ratio is 1÷4.5 and calcium-to-sulfur ratio ≥0.065. Above-mentioned impurities, in particular, are: Ni up to 0.25, Co up to 0.25, Mb up to 0.10, As up to 0.08, P up to 0.035, and N up to 0.015. Nonmetallic inclusions have two-layer structure: sulfide with oxide shell.

EFFECT: enhanced cutting ability and enabled cross hardenability of profiled iron up to 25 mm in diameter at the same process plasticity.

3 cl, 2 tbl