1. Technology Center， Xingtai Iron and Steel Co., Ltd., Xingtai 054027, Hebei, China 2. Hebei Province Wire Engineering Technical Research Center, Xingtai 054027, Hebei, China
Abstract：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.
2016, Vol. 26 
