The hardness of die steel is the main technical index of die steel. In order to keep its shape and size unchanged under high stress, the die must have enough hardness. The hot working die working at high temperature is required to maintain the stability of its structure and properties, so as to maintain enough high hardness. After a certain amount of heat treatment, die steel will change its own hardness. Next, Shandong die steel to share with you the common use of die steel hardness range.

除了模具钢本身质量不过关之外，模具钢的热处理硬度不够或者是过硬，都会使其使用寿命大大地减少。

In addition to the quality of die steel itself is not up to standard, the heat treatment hardness of die steel is not enough or too hard, which will greatly reduce its service life.

热处理硬度如果过高，就会导致材料开裂，裂纹等问题。在模具钢使用过程中也会大大的降低它的使用寿命。

If the hardness of heat treatment is too high, it will lead to material cracking, cracks and other problems. In the process of using die steel, its service life will be greatly reduced.

以上硬度一般为真空热处理高硬度，如超过此硬度，不但材料的性能方面不能保证，还会产生开裂与裂纹等问题。

The above hardness is generally high in vacuum heat treatment. If the hardness is exceeded, not only the performance of the material can not be guaranteed, but also cracks and other problems will occur.

1.模具截面大，钢材淬透性差，如大型模具选用了淬透性低的钢种。

1. The cross section of the die is large, and the hardenability of the steel is poor. For example, the steel with low hardenability is selected for the large mold.

方法：正确选用模具钢种，大型模具应选用淬透性高的高合金模具钢。

Solution: the correct selection of die steel, large-scale mold should choose high hardenability of high alloy die steel.

2.模具钢原始组织中碳化物偏析严重或组织粗大，钢中存在石墨碳和碳化物偏析、聚集。

2. Carbide segregation is serious or coarse in the original structure of die steel, and graphite carbon and carbide segregation and aggregation exist in the steel.

方法：加强原材料检查，确保原材料符合标准。对不良原材料钢材进行合理的锻造并进行球化退火处理，确保获得良好的组织。碳素工具钢不易多次退火，以防石墨化。

Solution: strengthen the inspection of raw materials to ensure that the raw materials meet the standards. Forging and spheroidizing annealing treatment should be carried out to ensure good microstructure. Carbon tool steel is not easy to be annealed many times to prevent graphitization.

3.模具锻造工艺不正确，锻造后未进行很好的球化退火，使模具钢球化组织不良。

3. The die forging process is not correct, and the spheroidizing annealing is not carried out well after forging, which makes the spheroidizing structure of die steel poor.

方法：严格执行锻造工艺和球化退火工艺，保证有良好的预备热处理组织。

Solution: strictly implement forging process and spheroidizing annealing process to ensure good preparation of heat treatment structure.

4.模具表面未除净退火或淬火加热时产生的脱碳层。

4. The decarburization layer produced during annealing or quenching heating is not removed from the die surface.

方法：热处理前应彻底模具表面的锈斑和氧化皮，并注意加热时的保护，尽量采用真空加热淬火或保护气氛加热淬火，盐浴加热时应进行良好的脱氧处理。

Solution: before heat treatment, rust spots and oxide scales on the mold surface should be completely removed, and attention should be paid to the protection during heating. Vacuum heating quenching or protective atmosphere heating quenching should be used as far as possible, and good deoxidation treatment should be carried out when heating in salt bath.