压力机机身的预紧力很大,以采用热胀冷缩原理预紧为宣。我们在一台800吨的油压机上采用工频加热法,实现了机身的可靠预紧。所谓工频感应加热法,是在预紧前,先将拉杆上的螺母尽可能地拧紧,并在所有拉杆和螺母上画第一条线 OA(图1)以确定初 Presses the body preload a lot, in order to use the principle of thermal expansion and contraction preload to declare. We use a heating frequency of 800 tons of hydraulic machine, to achieve a reliable body preload. The so-called frequency induction heating method, before the pre-tightening, the first nut on the rod as much as possible tighten, and in all the drawbar and nut draw the first line OA (Figure 1) to determine the beginning