How to loosen stainless steel screws and nuts?

If you have a liquid wrench or rust remover, WD-40, you can spray it and soak it for half a day, and combine the following methods to solve the problem:
1. Shock: For rusty screws and nuts, do not use a wrench to tighten them hard to prevent slipping the hexagonal corners of the screws and nuts, breaking the screws or damaging the wrench. At this point, a hammer can be used to gently shake the handle of the wrench. Generally, rusted screws can be shaken and unscrewed.
2. Knocking: Using a square top hammer to strike the edge of a rusted stainless steel nut can easily loosen the nut. For example, the fixing bolts and nuts at both ends of the bicycle pedal can be determined based on the thickness and metal structure of the pedal, and the amount of force used to strike the nut.
Non standard nuts on cast iron parts can be applied with slightly more force, while plastic parts should be lightly tapped. If it still doesn’t work, use a hammer to rotate and tap the nut in a circle in the direction to easily remove it.
3. Burn: Some screws are severely corroded and the above method is still ineffective, so “fire attack” can be used. Use a gas welding oxidation flame to fully grill non-standard screws and nuts, and then apply a little oil to the burnt red screws.
The purpose of heating screws is to cause them to expand under heat. The purpose of dripping oil is to quickly shrink the screw when cold, increase the gap between the screw and the stainless steel nut, and once the oil flows in, the nut can be unscrewed. However, if there are plastic devices nearby, use this method with caution.
4. Punching: The top of some stainless steel screws on some devices is corroded and deformed, making it impossible to remove them with a wrench or wire pliers, which can be done using impact method. Firstly, use a hammer and a turbine top screwdriver to strike a V-shaped groove vertically at the top of the screw.
Then, adjust the angle of the punching cone and impact along the direction of the screw. After loosening, you can use wire pliers to unscrew the screws. When the “one” or “ten” shaped screw slides, this method can also be used in conjunction with wire pliers to screw out the screw.
5. Welding: It is not uncommon to break screws when disassembling components. For screws with broken tops, electric drills are generally not used, as a slight mistake can damage the wire holes. A better way is to weld a long iron block onto the broken wire using electric welding. The cross-section of the iron block is determined by the diameter of stainless steel screws.