In die casting production, the most common forms of mold damage are cracks and cracks. Stress is the main cause of mold damage. Thermal, mechanical, chemical, and operational shock are all sources of stress, including mechanical and thermal stresses. Stresses arise from:

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Analysis of Causes for Damage of Die-casting Mold and
Preventive Measures
Translated By Jasmine HL
In die casting production, the most common forms of mold damage are cracks and cracks. Stress
is the main cause of mold damage. Thermal, mechanical, chemical, and operational shock are all
sources of stress, including mechanical and thermal stresses. Stresses arise from:
First, in the mold manufacturing process
1. The quality problem of blank forging. Some molds cracked after only a few hundred pieces
were produced, and cracks developed quickly. It may be that only the external dimensions are
guaranteed during forging, and dendritic crystals, inclusion carbides, shrinkage pores, bubbles
and other loose defects in the steel are extended and stretched along the processing method to
form streamlines. The final quenching deformation, cracking, brittle cracking during use, and
failure tendency have a great influence.
2. Cutting stress generated during turning, milling, planing, and other final processing. This stress
can be eliminated by intermediate annealing.
3. Grinding stress occurs during grinding of quenched steel, frictional heat is generated during
grinding, and a softened layer and a decarburized layer are generated, which reduces the thermal
fatigue strength and easily causes hot cracking and early cracking. After finishing the h13 steel, it
can be heated to 510-570 °C and maintained at a thickness of 25mm for one hour for stress relief
annealing.

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4. EDM produces stress. A bright white layer rich in electrode elements and dielectric elements is
produced on the surface of the mold, which is hard and brittle. This layer has cracks and stress.
EDM should use high frequency to minimize the white bright layer. It must be polished and
removed by tempering. Tempering is performed at the third tempering temperature.
2. Improper heat treatment during mold processing will lead to mold cracking and premature
scrap.
In particular, only the quenching and tempering is used, and then the surface nitriding process is
not performed, and surface cracking and cracking will occur after several thousands of die casting.
The stress generated during the quenching of steel is the result of the superposition of thermal
stress during cooling and the structural stress during phase transformation. Quenching stress is
the cause of deformation and cracking, and it must be tempered to eliminate the stress.
3. During the die-casting production process, the mold should be preheated to a certain
temperature before production. Otherwise, when the high-temperature metal liquid is filled, it
will cause chilling, which will cause the temperature gradient inside and outside the mold to
increase, forming thermal stress, and cracking the mold surface And even cracking. During the
production process, the mold temperature keeps rising. When the mold temperature is too hot, it
is easy to produce sticky molds, and the moving parts fail to cause damage to the mold surface. A
cooling temperature control system should be set to keep the working temperature of the mold
within a certain range.