After removing the hot pressing plate, brush off the rust with a steel brush, and then remove the rust spots with dilute hydrochloric acid (concentration 15%-20%) to expose the metal color of the pressing plate.
(2) Surfacing in corrosion zone with 422 electrode of 5 mm. Because one-sided surfacing can cause bending of pressure plate, double-sided surfacing should be adopted to offset the overlaying stress.
(3) In the gantry planer, the overlay welded pressure plate is planed on both sides, and the planed amount is 0.5mm.
If the welding seam of the plug cracks due to planing, it needs to be repaired. That is, after double-sided planer, each pressure plate will be tested one by one by steam pressure test, found that there are water droplets, do a good job of marking. After turning off the test steam, long grooves or circular grooves are grinded by an angular polisher at the weld seam of the water ball, then surfacing is done, and then polished by a polisher.