“20MnTiB钢冷镦高强度螺栓”是由铁道部科学研究院、大冶钢厂、上海市标准件制造公司、上海先锋螺丝厂、大桥局桥梁科学技术研究所、清华大学等单位共同研制成功的,1980年7月通过部级鉴定。产品质量完全达到日本同类产品的标准。我国在铁路桥梁、工业建筑等钢结构中使用高强度螺栓连接已有20多年历史了。这种高强度螺栓以往几乎都是用40B钢采用热镦工艺制造的。采用热镦工艺制造高强度螺栓的缺点是螺栓头部容易脱炭,表面光洁度差,外形尺寸难以保证,费钢料,产量低,工人劳动强度大,劳动条件差等。采用冷镦工艺制造高强度螺栓,表面光洁度高、外形尺寸准确、不会产 “20MnTiB steel cold heading high strength bolt” is jointly developed by the Ministry of Railways Science and Technology Research Institute, Daye Steel, Shanghai Standard Parts Manufacturing Company, Shanghai Pioneer Screw Factory, Bridge Bureau of Bridge Science and Technology, Tsinghua University and other units jointly developed In July 1980, it passed ministerial appraisal. Product quality fully meet the standards of similar products in Japan. Our country has used steel bolts of high strength for more than 20 years in railway bridges, industrial buildings and other steel structures. In the past, almost all of these high-strength bolts were made from hot-forged steel using 40B steel. The disadvantage of using hot upsetting technology to manufacture high strength bolts is that the head of the bolt is easy to decarburize, the surface finish is poor, the external dimensions are difficult to be guaranteed, the cost of steel material is low, the labor intensity of workers is heavy, and the working conditions are poor. Cold heading process for the manufacture of high strength bolts, surface finish, accurate dimensions, will not produce