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Chongqing Xicheng Hardware Manufacturing Co., Ltd.
Landline：023-42466988
Mobile phone：15909303966
Address：No. 7, Gusheng Road, Caojie Industrial Park, Hechuan District, Chongqing
Website：www.cqxiecheng.com.cn
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| Causes and preventive measures of die casting mould damage |
| Release time：2023/2/20 Source：Chongqing Xicheng Hardware Manufacturing Co., Ltd. Read：780Second |
1、 Causes of die casting production mold damage: In die casting production, the common forms of mold damage are cracks and cracks. Stress is the main cause of die damage. Thermal, mechanical, chemical and operational impact are all sources of stress, including mechanical stress and thermal stress, which are generated from:
（1） During mold processing and manufacturing
1. The quality of blank forging. Some molds have cracks after only a few hundred pieces have been produced, and the cracks develop rapidly. It is possible that the shape and size are only preserved during forging, while the loose defects such as dendritic crystal, carbide inclusion, shrinkage cavity and bubble in the steel are extended and elongated along the processing method to form a streamline, which has a great impact on the subsequent quenching deformation, cracking, embrittlement and failure tendency during use.
2. The cutting stress generated during final machining such as turning, milling and planing can be eliminated by intermediate annealing.
3. Grinding stress is generated during grinding of quenched steel, and friction heat is generated during grinding, resulting in softening layer and decarburization layer, which reduces the thermal fatigue strength and easily leads to hot crack and early crack. After finishing grinding, the h13 steel can be heated to 510-570 ℃, and the stress relief annealing can be carried out by holding for one hour every 25mm in thickness.
4. EDM produces stress. A layer of white bright layer rich in electrode elements and dielectric elements is produced on the surface of the mold, which is hard and brittle. This layer itself will have cracks and stress. High frequency shall be adopted during EDM to minimize the white bright layer, which must be removed by polishing and tempered at the third tempering temperature.
（2） Improper heat treatment in the process of die treatment will lead to die cracking and premature scrapping, especially if only quenching and tempering, no quenching, and surface nitriding process are used, surface cracking and cracking will occur after several thousand die casting times. The stress produced during steel quenching is the result of the superposition of the thermal stress during cooling and the structural stress during phase transformation. The quenching stress is the cause of deformation and cracking. Therefore, tempering must be carried out to eliminate the stress.
（3） During die casting production
1. Mold temperature The mold should be preheated to a certain temperature before production, otherwise when the high temperature metal liquid fills the mold, it will cause chilling, resulting in the increase of the temperature gradient of the inner and outer layers of the mold, forming thermal stress, causing the mold surface to crack, or even crack. During the production process, the mold temperature keeps rising. When the mold temperature is overheated, it is easy to cause mold sticking, and the failure of moving parts will lead to mold surface damage. A cooling temperature control system should be set to keep the working temperature of the mold within a certain range.
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