高温自然冷却后Q460高强钢高强度螺栓受剪连接力学性能试验研究

Experimental study on mechanical properties of shear connection of Q460 high-strength steel after natural cooling from high temperature

为了评估Q460高强钢高强度螺栓受剪连接高温自然冷却后的力学性能,采用电炉对受剪连接试件加热至目标温度后再自然冷却至常温,通过拉伸试验研究了过火温度、过火处理方法对受剪连接试件力学性能的影响。结果表明:不同的过火温度和过火处理方法对试件内部的表观特征以及在拉伸试验中的试验现象、板材间和板材与螺栓间的接触状态的影响是不同的;自然组主要是由于高温导致螺栓预紧力减小,而后装组主要是由于高温后板材表面新产生的浮锈引起抗滑移系数改变。不同过火温度和过火处理方法对试件的极限荷载、极限位移和抗拉刚度有很大影响;自然组试件的极限荷载和抗拉刚度总体随着温度的升高而减小,极限位移总体随着温度的升高而增加;后装组试件的极限荷载总体随着温度的升高而减小,而极限位移随着温度的升高而增加,抗拉刚度与常温试件基本一致。试件在高温自然冷却后表现出了较好的延性,试件的破坏形态均为其中一侧芯板外侧螺栓孔处净截面拉断。

In order to evaluate the mechanical properties of shear connection of Q460 high-strength steel after natural cooling from high temperature,the influence of temperature and treatment method on the mechanical properties of the shear connection specimens was studied by tensile test after that heated to target temperature by electric furnace and then natural cooling to normal temperature.The results show that the internal apparent characteristics of the specimens,the test phenomena in tensile tests,the contact states between plates and between plates and bolts are different from the effects of different temperature and treatment methods.The natural group is mainly caused by the decrease of the pre-tightening force of the bolt caused by the high temperature and the assembled after fire group is mainly caused by the change of the antisliding coefficient caused by the newly generated floating rust on the plate surface after the high temperature in addition to the change of the mechanical properties of the material itself.The ultimate bearing capacity,ultimate displacement and tensile stiffness of the specimens are affected greatly by different temperature and treatment methods.The ultimate bearing capacity and tensile stiffness of specimens in the natural group generally decrease with the increase of temperature,while the ultimate displacement generally increases with the increase of temperature.The ultimate bearing capacity of specimens in the assembled after fire group generally decrease with the increase of temperature,while the ultimate displacement increases with the increase of temperature,and the tensile stiffness of the specimens is basically the same as that of the specimens at room temperature.The specimen exhibits good ductility after natural cooling from high temperature and the failure mode of the specimen is the net section tensile fracture at the bolt hole outside one core plate.