Japanese steel s55c Japanese steel grades. Japanese steel will start with S. S55C carbon steel equivalent to China's quality 55 # steel. 45 # steel and belongs to the same carbon steel (1) High quality carbon steel properties. The steel is made furnace, open hearth, or oxygen converter steelmaking method of manufacturing a full static steel with superior workability, uniform microstructure features. The steel cheap, easily processed, suitable for induction hardening, flame hardening and other surface hardening treatment. The steel carbon content (mass fraction,%) ≥0.4, excellent wear resistance, but the ductility reduction, quenching deformation and cracking, it is extremely important quenching and tempering after quenching must, in order to avoid the occurrence of temper brittleness. The steel cutting difficult, need to improve ball handling cutting, tempering in principle to the hardness of 19 ~ 22HRC, to facilitate machining. (2) supply condition and hardness 149 ~ 192HBS, 183 ~ 255HBS, 229 ~ 285HBS. (3) the chemical composition (mass fraction,%) C 0.52 ~ 0.58, Si 0.15 ~ 0.35, Mn 0.60 ~ 0.90, P≤0.030, S≤0.035, Cu≤0.30, Ni≤0.20, Cr≤0.20. (4) Reference corresponding US steel AISI standard steel 1050/1055, JIS standard steel S50C / S55C, German DIN standard material number 1.1730. (5) Physical properties Tensile strength 735MPa, yield strength 372MPa, elongation δ522%, shrinkage of 38%, the impact toughness 35J / cm2, the compressive strength of 350MPa.