Failure mechanism and prevention of plastic deformation of die shell: die shell bears very large pressure and load when it is applied. It's usually not uneven. When the pressure of a small part of the die shell exceeds the yield limit of the die material at this temperature, the plastic deformation will occur in the form of sliding, twinning and grain boundary sliding, resulting in the failure of repair and damage of the die shell.

1、模貝断裂由裂纹萌生和裂纹扩展2个过程造成，其影响因素有：

1. The mode shell fracture is caused by two processes: crack initiation and crack propagation

（1）制定強度欠缺和截面过渡不平滑（突变、沟槽、锐角等）。

(1) Lack of strength and unsmooth section transition (abrupt change, groove, acute angle, etc.).

（2）制作质量差，工作面有粗糙，有原始瑕疵（如发际线、凹坑、凹坑等）。

(2) Poor production quality, rough working face, original defects (such as hairline, pits, pits, etc.).

（3）模具材料的冶金质量和加工质量对断裂失效有非常大危害，这表明在原材料的断裂韧性上。

(3) The metallurgical quality and processing quality of die materials have great harm to fracture failure, which shows that the fracture toughness of raw materials is very important.

（4）热处理方法和模貝质量将进一步危害。

(4) The heat treatment method and the quality of mould shell will be further harmed.

2、防止破裂没用的防范措施：

2. Preventive measures to prevent useless rupture:

（1）选取高质量无杂质钢；

(1) High quality and impurity free steel is selected;

（2）正确性合理性的结构设计；

(2) Correct and reasonable structural design;

（3）正确性锻造，改善原材料固有的结构瑕疵；

(3) Correct forging, improve the inherent structural defects of raw materials;

（4）有效性的初阶段热处理，使模块能够获得统一详尽的组织的基础；

(4) The first stage of the effectiveness of heat treatment, so that the module can obtain a unified and detailed organization of the basis;

（5）对模貝进行强韧化处理和表面强化处理。

(5) The mold shell was strengthened and toughened.