| 摘要 |
There is provided a steel material with superior surface pressure fatigue strength, comprising a machine structural steel used for power transmission components such as gears and shafts used in automobiles, industrial machines, and the like. The steel material comprises in mass %: C: 0.15 to 0.35%; Si: 0.30 to 0.95%; Mn: 0.10 to 1.00%; P: 0 to 0.030%; S: 0 to 0.030%; Cr: 0.80 to 2.30%; Cu: 0 to 0.30%; Al: 0.008 to 0.500%; O: 0 to 0.0030%; N: 0.0020 to 0.0300%; Ni: 0 to 3.00%; Mo: 0 to 0.29%; Ti: 0 to 0.200%; Nb: 0 to 0.20%; and B: 0 to 0.0050%; and the balance Fe and unavoidable impurities. The steel material has, in mass %, a parameter represented by Si+Cr-2Mn of 1.05 or more and a parameter represented by 0.7Si+2.5Mn+2.0Cr+2.5Ni+4.0Mo of 6.30 or less. |
