Prevention measures of stainless steel bolt and nut seizing

From the previous analysis, it can be seen that it is very inconvenient to disassemble the stainless steel fastener after it is killed. Even some methods or special tools are time-consuming and laborious, so it is particularly important to prevent the stainless steel fastener from being killed. The following introduces several methods to prevent the stainless steel fastener from seizing.

1) Select bolts and nuts of different materials to match.
2) To improve the performance of fastener itself, such as adding film on the fastener thread to prevent it from seizing, but this method has high cost and is rarely used at present.
3) Clean the thread, check whether the dentition is complete and continuous, and there is no impurity between the dentition.
4) Apply lubricant to the thread, such as molybdenum disulfide, grease, etc., evenly, and fill the thread bottom, covering the length of bolt head about (10 ~ 15) mm.
5) During fastening operation, screw the nut or bolt into (2-3) thread by hand first, and then screw it with torque wrench or socket wrench. The tightening force shall be uniform, and the tightening direction shall be perpendicular to the bolt axis, and the movable wrench or electric or pneumatic wrench shall not be used as far as possible.
6) When the electric or pneumatic wrench is used for pre tightening, excessive torque or speed shall be avoided. It shall be ensured that the nut will stop using when it contacts the gasket, and then the torque wrench shall be used for tightening. The tightening torque shall not exceed the specified torque value.

Through the analysis and summary, the stainless steel bolt and nut seizure is mainly caused by the excessive pressure and high temperature between the threads, which causes the oxide layer on the surface of the teeth to be damaged, and leads to the direct contact of the metal materials, further blocking, shearing and bonding. Therefore, in the process of using stainless steel fasteners, we not only need to understand the symptoms of fastener seizure, but also need to understand the principles and causes, as well as how to solve the problem after the occurrence of seizure, so as to better take preventive measures for stainless steel fastener seizure. In this way, the service life of stainless steel fasteners can be extended.