In the heat treatment process, precision molds are often deformed. In order to prevent this bad phenomenon, it is possible to control the deformation of the mold by using different methods to grasp the deformation law and analyze the causes of the deformation. of. In general, the precise deformation of the complex mold can be taken to prevent the following methods.
(1) fair selection. On the precision of the complex mold should choose a good material micro-deformation of the mold steel (such as air quenching steel), carbide segregation of the mold steel should be a serious casting and carried out on the larger and can not cast mold steel can be solid solution double fine heat treatment The
(2) mold structure design should be fair, the thickness should not be too poor, the shape should be symmetrical, for the deformation of the larger mold to grasp the deformation law, reserved processing margin, for large, sophisticated complex mold can be used composite structure.
(3) precision complex mold to be pre-heat treatment, to eliminate the mechanical processing of the residual stress generated.
(4) fair choice of heating temperature, control the heating rate, for complex and complex mold can be slow heating, preheating and other methods of equal heating to reduce the mold heat treatment deformation.
(5) to ensure the hardness of the mold under the conditions, try to use pre-cooling, grading cooling quenching or quenching process.
(6) on the sophisticated complex mold, with the premise of permission in the case, try to use vacuum heating quenching and quenching after the cryogenic treatment.
(7) for some sophisticated and complex mold can be pre-heat treatment, aging heat treatment, quenching and tempering nitriding heat treatment to control the accuracy of the mold.
(8) in the repair mold sand eyes, pores, wear and other defects, the use of cold welding machine and other small heat affected repair equipment to avoid the repair process of deformation.
There are many ways to deal with heat treatment processes, including, for example, plugging, boring, mechanical fixing, suitable heating methods, accurate selection of the cooling direction of the mold and the direction of movement in the cooling medium, etc. The fair tempering heat treatment process also reduces the precision Effective measures of mold deformation.