The mould steel cannot be heated too quickly

Update:28-11-2019
Summary:

The durability has a close relationship with the use of […]

The durability has a close relationship with the use of the die.If the durability is not good, it will lead to the early damage of the die and cannot be used normally. Therefore, when we use the die, we must understand what factors affect the durability of the die, which can not only improve the durability of the die. The performance of the die can also extend the life of the die.

1. Unreasonable impact of structural design

The structure of the die is the key to the durability of the die. The irrational structure can easily cause poor rigidity and uneven wall thickness distribution, and surface defects (such as surface oxidation, decarburization, cracks, and scars) will affect the performance of the material and cause early failure of the die .

2. the impact of die material selection

Choosing the right die material can prevent early die failure. Inclusions cause cracks inside the die, causing brittle fracture. In further heat treatment and use, the cracks further expand and cause the die to crack. When the steel is hot-worked and annealed, the decarburized layer sometimes remains after re-machining. Due to the different internal and external layer structures, the heat treatment cooling rate is not consistent, cracks are generated, and die cracks are caused. Containing higher carbon and alloy elements, there are more eutectic compounds, which cause cracks distributed along the band of carbides during quenching, and the cracks further expand during the use of the die, causing the die to crack.

3. Impact of die machining

The cavity part of the die or the fillet part of the punch often leaves a tool mark due to too deep penetration in the machining process, causing stress concentration, and cracks in the corresponding part of the die are further expanded during quenching, causing the die to crack. During electromachining, the die is heated to a high temperature, which causes the structure to change, that is, the abnormal layer of the electromachining is repeatedly affected by alternating stress, and the microcrack becomes a large crack, which causes the die to crack and be scrapped. Grinding will cause overheating of the grinding surface, or cause surface softening and reduced hardness, which will cause severe wear of the die in use, or grinding cracks due to thermal stress, * leading to early failure of the die.

4. the impact of die heat treatment specifications

After machining, the die should be heat treated such as quenching and tempering. Improper selection of process parameters such as heating temperature, length of time, cooling rate, protective atmosphere, etc. will affect the durability of the die. The mould steel contains more carbon and more alloying elements, which has poor thermal conductivity and cannot be heated too quickly.

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