高强度钢构螺栓连接副紧固轴力波动问题分析

针对ML20MnTiB生产的10.9级扭剪型钢构螺栓紧固轴力标准偏差大的问题进行了试验分析，通过进行螺母的磷皂化试验和螺栓热处理试验，表明螺母表面润滑状态、螺栓热处理工艺都影响紧固轴力检验结果，但不是造成紧固轴力标准偏差大的主要原因。通过更换新的车刀，将螺栓尾部凹槽位置螺栓直径由13.9减小为13.6 mm，凹槽底部曲率半径由0.17增大为0.5 mm，使紧固轴力平均值由176降低为167 kN，同时标准偏差由17.4降低为15.5以下，解决了紧固轴力标准偏差大的问题。

Analysis of tight axle strength fluctuation of high strength bolt sets for steel structures

For the problem of excess tight axle strength standard deviation of ML20MnTiB 10.9S torshear type bolt set used for steel structure, the phosphating and saponification experiment of nuts and the heat treatment experiment of bolts were carried out. The results showed that the lubrication condition of nut and the heat treatment process of bolt influenced the tight axle strength, but they were not the primary cause. After changing the lathe tool, the diameter of bolt tail groove reduced from 13.9 mm to 13.6 mm, and the radius of curvature of bolt tail groove enlarged from 0.17 mm to 0.5 mm. In consequence, the average of tight axle strength reduced from 176 to 167 kN, and the standard deviation of tight axle strength was reduced from 17.4 to 15.5 below.