Cracks in the mould after quenching are defects in the […]
Cracks in the mould after quenching are defects in the heat treatment, which will cause the mould to be unusable. Therefore, we should take relevant precautionary measures before mould quenching.
1. Strictly control the inherent quality of mould raw materials
2. Improve the forging and spheroidizing annealing processes, eliminate mesh, band, and chain carbides, and improve the uniformity of the spheroidizing structure. ,
3. The moulds after mechanical processing or cold plastic deformation should be subjected to stress-relief annealing (> 600 ℃) and then heated and quenched.
4. For moulds with complex shapes, asbestos should be used to block the threaded holes, bandage dangerous sections and thin walls, and graded or isothermal quenching should be used.
5. Annealing or high temperature tempering is required when repairing or refurbishing the mould.
6. the mould should be preheated during quenching and heating, precooling measures should be taken when cooling, and choose a suitable quenching medium.
7. the quenching heating temperature and time should be strictly controlled to prevent the mould from overheating and overburning.
8. The mould should be tempered in time after quenching, the heat preservation time should be sufficient, and the high alloy complex mould should be tempered 2-3 times.
9. Select the correct grinding technology and suitable grinding wheel.
10. Improve the mould EDM process and perform stress relief tempering.