Why do stainless steel fasteners lock during use? The reason is that a thin layer of chromium oxide is generated on the metal surface of stainless steel bolts and nuts during assembly and use, which has an anti-corrosion effect. When stainless steel fasteners are locked, the pressure and heat generated between the teeth will damage and erase the chromium oxide layer, causing the metal teeth to directly block/shear, leading to adhesion. When the stainless steel fastener is completely locked, it can no longer be removed or locked.

Stainless steel fasteners are locked in high-risk situations or industries

300 series fasteners have a high incidence of locking in situations such as flange connections (such as pump valves, printing and dyeing equipment), railway industry, curtain wall industry, and high-altitude locking operations, as well as electrical tool locking situations.

How to prevent locking of stainless steel fasteners

1. Choose products correctly. Before use, confirm whether the mechanical properties of the product meet customer needs (such as the tensile strength of bolts and the safety load of nuts)

2. The length of the bolt should be selected appropriately, based on 1-2 pitches of the exposed nut after tightening;

3. Before use, the product threads should be kept clean, and the product should be placed in a clean container

4. The nut must be rotated perpendicular to the axis of the bolt and must not tilt

5. During the tightening process, the force should not exceed the safe torque and should be uniform. Try to use a torque wrench or socket in conjunction

6. The locking speed should not be too fast, and it is recommended not to use an electric or pneumatic wrench

7. When using at high temperatures, it is necessary to cool down and do not rotate quickly to avoid rapid temperature rise and lock up.

8. Butter, molybdenum disulfide, graphite, mica, or talcum powder can be used to lubricate the internal and external tooth lines to reduce the occurrence of locking