Cause analysis and preventive measures of die casting mould damage



In the manufacturing of aluminum die casting, cracking and splitting are common ways of abrasive damage. The ground stress is the key cause of die casting mold damage. Heat, mechanical equipment, organic chemistry and practical operation impact are all sources of ground stress, including the ground stress of mechanical equipment and welding stress.

Cause analysis and preventive measures of die casting mould damage

In the manufacturing of aluminum die castings, the common ways of abrasive damage are cracking and splitting. The geostress is the key reason for the damage of the die casting mold. The heat, mechanical equipment, organic chemistry and actual operation impact are all the sources of the geostress, including the geostress and welding stress of mechanical equipment. The geostress is caused by the following factors:

1、 In the whole process of mold manufacturing, production and manufacturing

1. The quality problem of the products forged by rough embryo. Some abrasives cracked after only a few hundred pieces were manufactured, and the cracks are developing rapidly. It may be that the appearance specification was only guaranteed during forging. The loose defects such as crystalline reticular structure, mixed cementite, shrinkage cavity, and bubble in the stainless steel plate were widened and elongated along the production and processing mode, resulting in streamline, which is extremely harmful to the deformation, cracking, embrittlement, and failure tendency of the subsequent Z-end heat treatment

2. The drilling geostress caused by turning, milling, planing and other final production and processing can be eliminated by intermediate quenching

3. The ground stress, friction heat, softened layer and carburized layer produced by cutting of hardened steel reduce the thermal fatigue limit and are easy to cause hot cracks and initial cracks. After polishing, h13 steel can be heated to 510-570 deg; C. Heat preservation and quenching shall be conducted every 25 mm to eliminate ground stress

4. Wire EDM cutting causes ground stress, and a layer of white and clean electric grade elements and electrolytic medium elements are produced on the surface of the grinding tool, which is hard and brittle. This layer itself will have cracks and ground stress. When wire EDM cutting, high frequency should be selected to reduce the white mesh layer to a minimum. It must be polished and polished to remove, and quenching liquid should be used to quench at the three-stage quenching temperature

2、 Improper heat treatment of abrasive tools will lead to cracking and premature damage of abrasive tools

In many cases, only heat treatment is used instead of heat treatment, and then the surface nitriding process is carried out. After a thousand times of die casting, aluminum will appear surface cracking and crazing. The ground stress generated by heat treatment of steel is the result of the accumulation of welding stress and systematic ground stress during the whole refrigeration process. The ground stress generated by heat treatment is the cause of deformation and cracking, and it needs to be quenched to eliminate the ground stress

3、 In the process of aluminum die casting, the abrasives should be heated to a certain temperature before manufacturing

Otherwise, high temperature metal materials will produce chilling when filled with liquid, which will expand the temperature field on the inner surface of the abrasive tool, generate welding stress, and cause the surface of the abrasive tool to crack or even crack. During the processing process, the mold temperature continues to rise. When the mold temperature exceeds the temperature, it is very easy to cause the failure of mold adhesion and fitness parts, resulting in damage to the surface of the abrasive tool. The software of the refrigeration temperature control system should be set to keep the working temperature of the abrasive tool within a certain range

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