718 mold steel dimensions

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The structure of steel
The cast structure includes skeletal, carbide flakes and martensite or troostite alternately arranged ledesite, as well as black structure (& segregation) and white Structure (martensite and retained austenite). The as-cast structure and chemical composition of high-speed steel are particularly uneven and cannot be changed by heat treatment. Therefore, pressure processing must be performed to break the coarse eutectic carbides and distribute them evenly, and then use them to make various cutting tools and cutting tools. Mold "Wuchang Metal"
Forging Process
High-speed steel is prone to overburning when heated. Forging close to this temperature range is prone to cracking, and the heating temperature should be strictly controlled.
). Forging temperature range
It belongs to high alloy steel, which is characterized by slow heating rate and narrow forging temperature range. The initial forging temperature is ~&C, and the final forging temperature is ~&C.
). Determination of heating time
Steel has poor thermal conductivity and generally needs to be heated in sections. The heating temperature in the low temperature section is ~&C, and the heating time is generally calculated. Rapid heating at high temperature, heating time is generally calculated. When heating, in order to prevent overheating or overburning, the upper limit temperature must be strictly controlled. At the same time, the billet in the furnace must be filled with an appropriate amount and must be turned over continuously to ensure uniform temperature inside and outside.
Heat treatment process
The pre-treatment of the heat treatment process is annealing at a temperature of ~ degrees, holding for ~ hours, then preheating at one level, quenching in stages from one degree to one, and then tempering three times again. The heat preservation during fire is small.
Contains a large amount of alloy elements: poor plasticity and poor thermal conductivity. The thermal stress during rapid heating will cause it to deform and crack. Therefore, it must be preheated once it is heated to the quenching temperature. For those with complex shapes , should also be preheated at a time. The elements that mainly improve the red hardness need to be dissolved at a very high temperature, but too high a temperature will make the grains coarse, and the alloying elements will shrink the area, making the total The precipitation and eutectic temperatures increase, so one degree is chosen. Direct air cooling will precipitate secondary carbides, thereby reducing the red hardness of the steel.