On 2018-08-08 14:48:54
Heat treatment deformation prevention
The cause of deformation of sophisticated mold is often complex, but as long as we grasp the deformation law, analysis of its causes, using different methods to prevent mold deformation can be reduced, but also can be controlled. Generally speaking, the heat treatment deformation of precision complex mold can be taken the following methods to prevent.
(1) reasonable selection of materials. Micro deformation die steels with good materials (such as air quenching steel) should be selected for precision and complex dies. Mold steels with severe carbide segregation should be forged reasonably and tempered with tempering heat treatment. For large and unforged die steels, double refining heat treatment of solid solution can be carried out.
(2) mold structure design should be reasonable, thickness should not be too large, shape should be symmetrical, for large deformation mold to master the deformation law, reserved processing allowance, for large, sophisticated complex mold can be used combined structure.
(3) pre-heat treatment shall be carried out for sophisticated and complicated molds to eliminate residual stress generated during machining.
(4) reasonable selection of heating temperature, control of heating speed, for the sophisticated mold can be used to slow heating, preheating and other balanced heating methods to reduce the mold heat treatment deformation.
(5) under the premise of ensuring the hardness of the mold, precooling, graded cooling quenching or warm quenching process shall be adopted as far as possible.
(6) for precision and complex molds, if conditions permit, use vacuum heating and quenching and post-quenching cryogenic treatment as far as possible.
(7) preheat treatment, aging heat treatment and tempering nitriding heat treatment can be used to control the precision of some sophisticated molds.
(8) in the repair of mold sand hole, porosity, wear and other defects, choose cold welding machine and other repair equipment with small thermal impact to avoid deformation in the repair process.
In addition, the correct operation of heat treatment process (such as hole plugging, hole binding, mechanical fixation, appropriate heating method, correct choice of mold cooling direction and movement direction in the cooling medium, etc.) and reasonable tempering heat treatment process is also an effective measure to reduce the deformation of sophisticated mold.