On 2018-08-08 14:48:54
The cause of die deformation in heat treatment
In this paper, the deformation status and causes of the precision and complex die are studied, and the measures to reduce and control the deformation of the precision and complex die are discussed, so as to improve the quality and service life of the die products.
Causes and preventive measures of die deformation after heat treatment
It is often found in the factory that some molds with complex shape and high precision require large deformation after heat treatment. After careful investigation, it is found that there is no pre heat treatment in the machining and final heat treatment of the molds.
1. Cause of deformation:
The superposition of the residual stress and the stress after quenching in the machining process increases the deformation of the die after heat treatment.
(1) After rough machining and before semi finish machining, one stress relief annealing shall be carried out, i.e. (630-680) ℃× (3-4) H furnace cooling to below 500 ℃ air cooling, or 400 ℃ × (2-3) H stress relief treatment.
(2) Reduce quenching temperature and residual stress after quenching.
(3) The quenched oil is used for air cooling (graded quenching) at 170 ° C.
(4) The quenching residual stress can be reduced by using the isothermal quenching process.
The above measures can reduce the residual stress and the deformation of the die after quenching.