在高压蒸汽鍋爐、高压容器的凸緣,變号載荷的構件;尤其是在內燃机,以及其他類似地方的螺丝和螺栓,必須正確地擰緊。这对於避免故障來说,有很大意义。在这些工作情况下,螺絲擰得过紧和过鬆都有同样的危險。在螺帽上所施扭矩大於計算值,对於低碳鋼螺絲能產生硬餘變形;而对高碳合金鋼螺丝(如連桿螺絲),則產生高的初应力而常常拉斷。為了消除这种現象,现在採用測力計扳手。本文所叙述者,卽為作者所建议的定值扭矩 In high pressure steam boilers, flanges of high pressure vessels, variable-load components; especially in internal combustion engines, and other similar places, the screws and bolts must be properly tightened. This is great for avoiding problems. In these conditions, the screws are too tight and too loose are the same danger. The torque applied on the nut is greater than the calculated value, for the low-carbon steel screws can produce hardened deformation; and high-carbon alloy steel screws (such as connecting rod screws), the resulting high initial stress and often pulled off. In order to eliminate this phenomenon, now use a dynamometer wrench. As described in this article, 卽 is the recommended torque rating by the author