Stainless steel has slow heat conduction and large friction coefficient. The heat generated during tightening will weld the metal particles together, resulting in locking. There are three ways to avoid it: first, slow down, it is strictly forbidden to install high-speed electric tools, and it needs to be screwed in at low speed; second, lubricate, apply butter, wax or special anti-seizure agent to the threads before installation; third, washer, use flat pad Or spring washer separates the nut and the connected part to reduce friction and heat generation. If it is slightly locked, do not forcibly spin it out, but drip rust remover and try again.