The working principle of the stainless steel nut is self-locking by the friction between the stainless steel nut and the bolt. However, the reliability of this self-locking will be reduced in dynamic loads. In some important occasions, we will take some anti-loosening measures to ensure the reliability of the locking of stainless steel nuts. Among them, locking stainless steel nuts is one of the anti-loosening measures.
In fact, anyone who knows chemistry understands that all metals react with oxygen in the atmosphere to form an oxide film on the surface. Unfortunately, the iron oxide formed on ordinary carbon steel continues to oxidize, causing the corrosion to continue to expand and eventually forming holes. You can use paint or oxidation-resistant metals (such as zinc, nickel and chromium) for electroplating to ensure the surface of carbon steel, but, as people know, this protection is only a thin film. If the protective layer is damaged, the steel below will begin to rust. The corrosion resistance of stainless steel depends on chromium, but because chromium is one of the components of steel, the protection methods are different.
Due to the essential difference between stainless steel and carbon steel, stainless steel has good ductility, and improper use can easily cause the stainless steel screw and nut to be unable to unscrew after being matched. It is commonly known as "locking" or "seizing". Therefore, pay attention to the following points when using:
(1) The nut must be screwed perpendicularly to the axis of the screw, do not tilt.
(2) During the tightening process, the force must be uniform, and the force must not exceed the safe torque. (safe torque table attached)
(3) Use tuft wrenches or socket wrenches as much as possible, and avoid using adjustable wrenches or electric wrenches.
(4) It must be cooled when used in a high temperature state, and do not rotate quickly during use, so as to avoid the rapid rise in temperature and cause lockup.