Prevention of deformation during heat treatment

  The causes of deformation of precision and complicated molds are often complicated, but as long as we master the deformation rules and analyze the causes, the use of different methods to prevent mold deformation can be reduced and controlled. In general, the following methods can be used to prevent heat treatment deformation of precision and complex molds.

 1. Reasonable selection of materials. For precision and complicated molds, choose good-deformation mold steel (such as air quenched steel), and forge mold carbide with severe segregation of carbides for reasonable forging and quenching and tempering heat treatment. For large and unforgeable mold steels, solid solution double Refine heat treatment.

  2. The design of the mold structure should be reasonable, the thickness should not be too wide, the shape should be symmetrical, the deformation rules should be mastered for the molds with large deformation, and the processing allowance should be reserved. For large, precise and complex molds, a combined structure can be used.

  3. Precise and complex molds should be pre-heat treated to eliminate the residual stress generated during the machining process.

  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 used to reduce mold heat treatment deformation.

  5. Under the premise of ensuring the hardness of the mold, try to use pre-cooling, graded cooling quenching or warm quenching process.

  6. For precise and complex molds, as far as conditions permit, try to use vacuum heating quenching and cryogenic treatment after quenching.

  7. For some sophisticated molds, pre-heat treatment, aging heat treatment, tempering and nitridation heat treatment can be used to control the precision of the mold.

  8. When repairing defects such as die trachoma, blowhole, wear, etc., use cold welding machines and other repair equipment with small thermal impact to avoid deformation during repair.

  In addition, correct heat treatment process operations (such as plugging holes, binding holes, mechanical fixing, suitable 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 process are also reduced precision and complexity Effective measures for mold deformation.

 

Heat treatment sub-process

Annealing Heat treatment

Vulcanization Heat treatment

Hardening Heat treatment

Relieve stress Heat treatment