Selections: First, the cause of die-casting die-casting production damage: die-casting production, the most common form of mold damage is cracking, cracking. Stress is the main cause of mold damage. Thermal, mechanical, chemical, operational impact is the source of stress, including mechanical stress and thermal stress, stress generated in: (a) in the mold manufacturing process precision mold frame

1, rough forging quality problems. Some molds produce cracks on only a few hundred pieces, and cracks develop rapidly. It may be forged only to ensure the appearance size, and dendrites in steel, inclusions carbide, shrinkage, bubbles and other loose defects along the processing method is extended to form a streamline, this streamline after the The final quenching deformation, cracking, the use of brittle fracture, the failure of a great influence.

2, in the car, milling, planing and other finishing the cutting stress generated, this stress can be eliminated by intermediate annealing.

3, hardened steel grinding grinding stress, grinding friction heat, resulting in softening layer, decarburization layer, reducing the thermal fatigue strength, easily lead to thermal cracking, early cracks. H13 steel after grinding, heating can be taken to 510-570 ℃, with an insulation thickness of 25mm per hour for stress relief annealing.

4, EDM stress. Die surface layer of a collection of electrode elements and dielectric elements enriched white bright, hard and brittle, this layer itself will have cracks, stress. EDM should be used in high frequency, so that the white layer to minimize the polishing method must be removed, and tempering, tempering temperature in the tertiary.

(B) mold processing process

Improper heat treatment will lead to mold cracking and premature scrapped, especially only with quenching and tempering, and then the surface nitriding process, surface die cracking and cracking after die-casting thousands of molds.

Steel quenching stress, the cooling process is the thermal stress and phase transition when the stress superimposed on the organization, quenching stress is the cause of deformation, cracking, solid must be tempered to eliminate stress.

(C) in the die-casting production process

1, mold temperature

Mold before production should be preheated to a certain temperature, or when the high temperature liquid metal filling chilling, resulting in increased temperature gradient inside and outside the mold, the formation of thermal stress, the mold surface cracking, or even cracking.

In the production process, the mold temperature continues to rise, when the mold temperature is too hot, prone to sticky mold, moving parts failure resulting in mold surface damage.

Should set the cooling temperature control system to maintain the mold temperature in a certain range.