Locking occurs when assembling stainless steel screws and stainless steel nuts. What is lockup? Locking actually refers to the phenomenon that bolts and nuts are locked during the tightening process. Stainless steel screw manufacturers usually occur between the stainless steel screw and the stainless steel nut, so it is also called screw locking or seizure.
Why do non-standard stainless steel screws lock up? Analyzing the reasons, there are the following points:
1. The inclination angle of the thread fitting and the softer characteristics of stainless steel are likely to cause lockup. During the installation process, uneven force or inclination will maximize the inclination of the central axis of the screw and the nut, and the more likely it is to damage the tooth pattern and cause occlusion; the hardness of the stainless steel screw is relatively soft, and the iron will fall off if rubbed during the tightening process Chips will stick and not fall, thereby interfering with the smooth in and out of the threads, causing the bottom and top of the tooth to die.
2. Excessive locking force and low thermal conductivity of stainless steel can easily lead to thread locking. The stainless steel screw nut generates heat due to friction during rotation. The thermal conductivity of stainless steel is relatively low (basically in the range of 10-30w/mc°, about 1/3 of carbon steel), when the pressure and heat generated destroy the chromium oxide layer (the oxide layer that is not easy to rust for stainless steel) At this time, the metal tooth pattern is directly blocked/sheared, and the characteristics of stainless steel are soft, and then adhesion occurs. The greater the tightening force, the greater the heat generated, and the more easily the stainless steel in the screw shank part will be stuck.
Regarding the locking phenomenon of stainless steel screws, how to avoid the locking phenomenon?
1. Keep the center axis of the screw and nut perpendicular to the locked surface, and reduce the inclination angle of the center axis of the screw and nut;
2. Use torque wrenches or barrel wrenches as much as possible to avoid excessive force and control the torque within the torque range of the safety stock;
3. Try not to use electric wrenches, use manual wrenches to slow down the locking speed, keep the threads clean, reduce heat energy, and reduce adhesion;
4. Choose screws and nuts of different materials for coordinated use to avoid adhesion of the same material;
5. Choose anti-locking products or use anti-locking lubricants to reduce friction and avoid locking.