The causes of deformation of precision and complex molds are often complicated, but we only need to grasp the law of deformation, analyze the causes, and adopt different methods to prevent the deformation of molds, which can be reduced and controlled. Generally speaking, the following methods can be taken to prevent the heat treatment deformation of precision and complex molds.
(1) Reasonable selection of materials. For precision and complex molds, micro-deformed die steels with good materials (such as air-quenched steel) should be selected. For die steels with serious carbide segregation, reasonable forging and quenching and tempering heat treatment should be performed. For large and unforgeable die steels, solid solution double Refine the heat treatment.
(2) The mold structure design should be reasonable, the thickness should not be too wide, the shape should be symmetrical, the deformation law should be mastered for the larger deformed mold, and the machining allowance should be reserved. For the large, precise and complex mold, a combined structure can be used.
(3) Pre-heat treatment of precision and complex molds is required to eliminate residual stress generated during machining.
(4) Reasonably select the heating temperature and control the heating speed. For precision and complex molds, slow heating, preheating and other balanced heating methods can be adopted to reduce the heat treatment deformation of the mold.
(5) On the premise of ensuring the hardness of the mold, try to use pre-cooling, hierarchical cooling quenching or warm quenching process.
(6) For precision and complex molds, when conditions permit, try to use vacuum heating quenching and cryogenic treatment after quenching.
(7) Pre-heat treatment, aging heat treatment, tempering nitriding heat treatment can be used to control the precision of the mold for some sophisticated molds.
(8) When repairing mold blisters, pores, wear and other defects, use cold welders and other repair equipment with low heat impact to avoid deformation during the repair process.
In addition, correct heat treatment process operations (such as plugging holes, tying holes, mechanical fixing, appropriate heating methods, correct selection of the cooling direction of the mold and the direction of movement in the cooling medium, etc.) and reasonable tempering heat treatment processes are also reducing precision and complexity Effective measures for mold deformation.
Heat treatment process:
Annealing heat treatment
Vulcanization heat treatment
Hardening heat treatment
Stress relief