基于普通螺栓扭矩系数的紧固力矩限值试验研究

EXPERIMENTAL RESEARCH ON TIGHTENING TORQUE LIMITED VALUE BASED ON COMMERCIAL BOLT TORQUE COEFFICIENT

在输电线路铁塔中,螺栓连接是节点的一种常用连接方式。为保证连接的可靠性,施工时常采用紧固力矩对预紧力进行控制。扭矩系数作为紧固力矩和预紧力关系的关键参数,对合适的紧固力矩范围的确定起着重要作用。输电线路相关规范规定了螺栓紧固力矩的下限,但未规定上限。对不同等级、不同规格、镀锌前后普通螺栓的屈服荷载和扭矩系数进行了测定,采用两种方法对紧固力矩的上限进行计算,并与工程机械相关规范给出的紧固力矩上限进行对比。结果表明:工程机械相关规范给出的紧固力矩上限普遍与试验值有较大程度的偏差,两种方法得到的预紧力也存在不同程度的偏差,产生这种偏差的主要原因是扭矩系数标准差的差异。

Bolts connection is a common way to connect joints in transmission line iron towers. Tightening torque has been widely used in construction to control pretension force in order to ensure the reliability of connection. As key parameter of relation between tightening torque and pretension force,torque coefficient plays an important role to determine suitable tightening torque range. Relevant regulations of transmission line stipulated the lower limit of bolt tightening torque,but did not define the upper limit. In the paper,the yield load and torque coefficient of ordinary bolts with different classes and specifications before and after galvanization were measured,and the upper limit of the tightening torque was calculated by two methods,which was compared with the tightening torque of engineering machinery. The results showed that the upper limit of the tightening torque was generally deviated from the test values and the pretension force of the two methods had a great deviation,and the main reason for the deviation was the differences of the standard deviation of the torque coefficients.