Two metal plates, one copper, one carbon steel, with an area of 20mm*20mm, need to be welded face to face, and then the temperature should be 300℃, want to use silver welding, personal manual operation can do it?

There are some differences in linear thermal expansion coefficient. It is not recommended to weld the whole contact surface. The temperature will release the stress and affect the solder joint strength.It is suggested to spot weld the two pieces in the middle and around with the electric welding machine for a circle, and then do silver brazing at intervals, so that the stress is released through the gap, temperature resistance is basically no problem.