钢网架螺栓球节点用高强度螺栓过火冷却后力学性能试验研究

螺栓球钢网架结构火灾后,其螺栓球节点用高强度螺栓剩余力学性能对结构整体安全至关重要.通过对螺栓球钢网架常用的10.9 s级40Cr和35CrMn螺栓球节点用高强度螺栓进行过火冷却后力学性能试验,主要控制参数为过火温度和冷却方式,并对其力学性能变化规律进行了分析,得到两种高强螺栓过火冷却后的抗拉强度变化规律.结果表明:4...

Experimental study on mechanical properties of high strength bolts used in steel grid bolted spherical joints after fire

After a fire, the residual mechanical properties of high strength bolts of bolt ball joints are very important to the overall safety of the structure. The mechanical properties of 40Cr and 35CrMo high strength bolts of 10.9s grade commonly used in grid structures were tested after fire. The main control parameters in this experiment were the fire temperature and the cooling mode, whose effects on the mechanical properties were analyzed. It is shown from the results that when the fire temperatures of 40Cr bolt and 35CrMo bolt are lower than 500℃ and 400℃, respectively, the fire temperature and cooling mode have little influence on the mechanical properties of high strength bolts. when the fire temperature of 40Cr bolt is between 500℃ and 800℃, or the fire temperature of 35CrMo bolt is between 400℃ and 800℃, the fire temperature has a great effect on the mechanical properties of high strength bolts, while the cooling mode only has a significant effect on the elongation. The cooling mode has a great effect on the mechanical properties of high strength bolts when the fire temperature is more than 800℃. The tensile strength of bolts can be calculated according to the fitting formulas proposed in this paper when the fire temperature is no more than 800℃. When the over fire temperature is less than 800℃, the tensile strength of bolts under different cooling methods can be calculated according to the formula in this paper. The maximum error of the formula is 3.78% for 40Cr bolt and 6.79% for 35CrMn bolt.