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      1. 歡迎訪問濟南立強模具有限公司!



        來源:http://www.lasagnafarm.com/ 日期:2021-12-24

        1) Tensile strength and yield strength
        Different types of dies focus on the specific mechanical properties required by forging die materials. At the same time, we should not only consider the mechanical properties at room temperature and ignore the more important performance indexes at actual working temperature; Do not pursue comprehensive high indicators that are blindly divorced from reality. For example, in the case of hard to deform alloy forgings with high cold forging deformation resistance, when the stress borne by the die exceeds the tensile strength of the forging die material at the service temperature, the die will be cracked and scrapped; If the stress borne by the die exceeds the yield strength of the forging die material at the service temperature, permanent deformation such as die collapse will be caused, resulting in out of tolerance of the forging. Under this condition, forging die materials with high tensile strength and yield strength should be selected. Generally, the tensile strength of forging die materials should be greater than 30% of the stress.
        2) Impact toughness, reduction of area and elongation
        Because the selection of impact toughness index of forging die material is closely related to the properties of forging load, for the dies used by impact load equipment such as forging hammer and screw press, if the impact toughness of forging die material is low, the dies may crack and be scrapped; Under this condition, forging die materials with high impact toughness should be selected.
        For forging die materials with high area shrinkage and elongation, they can continue to be used in the case of small cracks without breaking soon. Therefore, under the permission of tensile strength, yield strength and hardness indexes, the area shrinkage and elongation shall be improved as much as possible.
        3) Hardness
        In view of the fact that the hardness is not only related to the strength index, but also closely related to the wear resistance of the die, the hardness (or wear resistance) shall be improved as much as possible under the allowable conditions of impact toughness, reduction of area and elongation. The hardness and red hardness of forging die are important properties of forging die materials. The die should be able to keep its shape and size unchanged when working at high temperature.
        As we all know, there is a contradictory relationship between the tensile strength, yield strength, hardness, reduction of area, elongation and impact toughness of the same forging die material. If the former is improved, the latter must be sacrificed, which requires the corresponding performance matching to be selected according to the actual working environment of the specific die.
        It must be pointed out that the hardness of materials can not only reflect the strength level to a certain extent, but also have a corresponding relationship between hardness and wear resistance. Generally, materials with high hardness have good wear resistance. Therefore, many forging die materials usually only simply specify the requirements for hardness.
        2. Fatigue performance
        The fatigue properties of forging die materials include mechanical fatigue and cold and hot fatigue. The hot working die circulates alternately from high mechanical load to zero mechanical load and 200 ℃ ~ 600 ℃ temperature range for a long time. The superposition of stress caused by loading and unloading of these two pulses will cause microcracks on the surface of the die bore over time; The further development of microcracks will accelerate die wear and produce fragments, resulting in die failure. Therefore, it is required that the forging die material should have good mechanical fatigue resistance and cold and hot fatigue resistance.

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