Plug shell mold quenching crack causes and preventive measures

In order to improve the service life of the plug shell mould, mould processing during the template for heat treatment. But often will appear the template quenching crack in the hot place, what is the cause of this phenomenon? And how to prevent? Plug shell mold quenching crack reasons: 1) Template materials exist serious meshy carbide segregation. 2) Templates are mechanical processing or cold plastic deformation stress. 3) Template improper heat treatment operation ( Heating or cooling too quickly, improper selection, cooling quenching cooling medium temperature is too low, the cooling time is too long, etc. ) 。 4) Template complex shape, thickness, with sharp corners and threaded hole, etc. , make the thermal stress and organization stress is too large. 5) Template quenching heating temperature is too high cause overheating or burnt. 6) Template after quenching tempering time insufficient tempering heat preservation time. 7) Quench heating template repair, without intermediate annealing and quenching again. 8) Template of the heat treatment, improper grinding technology. 9) Template edm after heat treatment, have higher tensile stress exist in the hardening layer and microscopic cracks. The plug shell mold quenching crack prevention measures: 1) Strictly control the immanent quality of mold material 2) Improve forging and spheroidizing annealing process, eliminate mesh, belt, chain carbide, improve spheroidizing together all of the organization. 3) After machining or after cold plastic deformation of mould should be to stress annealing (> 600℃) After quenching. 4) Of complicated shape template should use asbestos jams threaded hole, bandaging and thin wall, the dangerous section and using level of quenching and isothermal quenching. 5) Repair or refurbish templates require annealing or high temperature tempering. 6) Template should take when quenching heat preheating, cooling the precooling measures, and select suitable quenching medium. 7) Should strictly control the quenching heating temperature and time, to prevent overheating and burnt mould. 8) Template shall promptly tempering after quenching, heat preservation time to fully, high alloy complex mould should be 2 - tempering 3 times. 9) Select the correct grinding process and the appropriate grinding wheel. 10) Improve the edm process templates, and to stress tempering.