摘要
研究目的:目前我国主要的几条重载铁路铺设使用了当今世界上断面最大的75 kg/m钢轨,国外重载铁路发达的国家则大量使用美国铁路保养协会钢轨技术条件(AREMA-2004)中规定的136RE(68 kg/m)断面的钢轨,且较为成熟。因此开展68 kg/m钢轨的试验研究,可为我国重载铁路钢轨的铺用提供更多的选择,对发展我国重载铁路运输具有重要的意义。研究结论:热轧钢轨室温抗拉强度为1 080 MPa,轨顶面硬度达到300 HB;成品钢轨中的氢含量为0.5×10-4%,氧含量为12.3×10-4%;轨头踏面及轨角处的显微组织为片状珠光体及少量铁素体;轨底最大残余拉应力为200.2 MPa;-20℃断裂韧性KIC为32.5MPa.m1/2;裂纹尖端强度因子ΔK=10 MPa.m1/2及13.5 MPa.m1/2时疲劳裂纹扩展速率da/dN分别为9.55 m/Gc和31.98 m/Gc。由以上试验研究结果可知,我国68 kg/m热轧钢轨的各项性能指标均达到了《68 kg/m钢轨暂行技术条件》的要求,可以上道试铺。
Research purposes： Now 75 kg/m rails are applied on heavy haul railway lines in domestic, hut AREMA 136RE （68 kg/m） rails are applied widely and maturely on heavy haul railway lines in countries which have developed heavy haul railway network. It is necessary to investigate properties of 68 kg/m （136RE） rails in order to provide more type of rails for heavy haul railway in domestic. Research conclusions： The ultimate tensile strength at room temperature of hot - rolled rails is 1 080 MPa, and hardness of tread is up to 300 HB. The H and O contents of finished rails are 0.5 × 10^ -4% and 12.3 × 10^-4% respectively. The microstructure of tread and gauge corner is consist of pearlite and a little ferrite. The largest residual tensile stress in rails bottom is 200.2MPa. The fracture toughness （Kit） at - 20 ℃ is 32.5 MPa · m^1/2. When the stress intensity factor （△K） is 10 MPa · m^1/2 and 13.5 MPa ·m^1/2, the fatigue crack growth rate （da/dN） is respectively 9.55 m/Gc and 31.98 m/Gc All results show that the 68kg/m hot -rolled rails satisfy requirements of ＂ tentative technical specifications of 68kg/m rails＂, and could be laid on heavy haul railway line.
出处
《铁道工程学报》
EI
北大核心
2008年第9期30-34,共5页
Journal of Railway Engineering Society
