1. Quality problems of burr forged products
Some mold shells only produce dozens of mold shells, so there will be gaps. Although it is very likely that only external specifications are ensured during forging, loose defects such as dendrites, cementite mixing, constricted pores and bubbles in the steel are widened along the processing method, resulting in a streamlined shape.

2. The drilling internal stress formed in the whole process of CNC lathe, cutting, scraper and other finishing processes can be removed according to the middle baking.
3. When grinding quenched steel, internal cutting stress is caused, friction heat is caused during cutting process, soft layer and carburized layer are produced, which reduces thermal fatigue limit, and is very easy to cause thermal cracks and premature cracks. For H 13 steel, heat to 510-570°C after cutting for 1 hour per 25 mm thickness, for internal stress relief and baking.
4. Internal stress of spark discharge machining. The surface layer of the mold shell causes a variety of white layers of electrical elements and electric polarization elements, and the hard and brittle layer itself has gaps and internal stress. In the whole process of spark discharge machining, it is necessary to use high frequency to avoid white layer as much as possible, remove the grinding and polishing method, carry out quenching treatment, and carry out at the tertiary quenching temperature.