回火工艺对贝氏体辙叉心轨钢组织性能影响研究

Study on Effect of Tempering on Microstructure and Properties of Bainitic Rail Steels for Switch- Point Component

研究了Si—Mn—Cr低碳贝氏体钢在正火和回火过程中的组织转变和性能变化。结果表明:经350℃回火后具有良好的强韧配合,新型贝氏体钢屈服强度为1 196 MPa,抗拉强度为1 437 MPa,伸长率和断面收缩率分别为13%和50%,冲击韧性为72 J/cm^2,强韧性配合明显高于普通及淬火珠光体钢轨钢。而在450℃～600℃回火时出现明显的回火脆性。通过研究回火后的组织转变及残余奥氏体热稳定性、机械稳定性的变化,探讨了无碳贝氏体韧化及脆化机理,提出了适于该钢的最佳回火工艺。

Microstructure and mechanical properties of a kind of new low alloy bainitic steel was studied after normalizing and tempering.The results of tensile test and Charpy U notch(CUN) impact test showed that,when the bainitic steel was tempered at 350℃,it has better technical behavior:its yield strength,ultimate tensile strength,elongation,reduction of area and Charpy U notch(CUN) impact toughness were 1,196MPa,1,437MPa,13%,50%and 72J/cm2,respectively.The steels appear obviously temper brittleness when tempered ...