What's the deal with brake pads and steel backs?

Brake pads include steel backs, friction materials and other main parts and other auxiliary components, that is: steel backs are part of the brake pads.
The steel back mainly plays a fixed role. 1. In terms of manufacturing: the powder friction material (mostly) undergoes chemical and physical action at high temperature and high pressure, and is pressed onto the steel back to form a solid (some are also separately formed and then riveted), among which Some will add a cushion between the steel back and the friction material. This part has no friction effect, mainly for noise reduction, heat insulation and buffering. - that is, fixed left and right;
2. In terms of use: The braking process is mainly to generate friction between the fixed brake pad and the brake disc that rotates with the wheel to achieve the purpose of braking. The friction force is generated by the friction between the friction material and the brake disc. One force is to prevent the wheel. Turning and braking, the opposite force acts on the car to generate torque, and this force is transmitted to the car through the steel back (through the brake caliper), which is fixed to the force transmission.