A heat treatment process for producing high-quality mold steel in a trolley furnace

Abstract

The invention discloses a heat treatment process for producing high-quality mold steel in a trolley furnace, which is characterized in that it comprises the following process steps: (1) stacking the mold steels in sequence from thick to thin and loading them into the trolley furnace; Steel support; (2) Keep warm for 2 hours after heating up to 300℃~350℃ at a heating rate of 40℃ / h; (3) Continue heating up to 630℃~660℃ at a heating rate of 40℃ / h and then keep warm for 8~12h; (4 ) Under the premise of keeping the reversing fan working, cool it to 300°C with the furnace and then release it. (5) In the above process stage, when the temperature difference between the two sides of the steel plate is greater than 20°C, the reversing fan is reversing. The heat treatment process described in the invention effectively solves the problems of low heating efficiency and poor temperature control precision of the trolley furnace. This process produces high-quality mold steel plates with good shape and hardness that meets the standard requirements. The hardness difference between the same plate is less than 5HB, and the hardness difference between different plates is less than 10HB. Uniform hardness, good cutting performance, suitable for processing complex molds.

Description

Technical field [0001] The invention relates to a heat treatment process of die steel used in industry, and belongs to the technical field of metallurgical processing. Background technique [0002] Moulds are the main processing tools for manufacturing parts in machinery manufacturing, radio instruments, motors, electrical appliances and other industrial sectors. With the gradual development of the industry, various industries have higher and higher requirements for the accuracy of parts, which puts forward higher requirements on the processing and forming performance of die steel. Hardness uniformity is an important indicator of the cutting performance of mold steel, that is, mold steel is required to have good hardness uniformity. Due to the high alloy content of the die steel, the internal stress generated by rolling is large, and a long heat preservation time is required to uniform the structure during heat treatment. The production of mold steel in a continuous furnace has...

AI Technical Summary

Problems solved by technology

Production of mold steel in continuous furnaces has low production efficiency and high cost, which seriously occupies the production capacity of the production plant, and the trolley furnace can solve this problem as an auxiliary heat treatment equipment

[0003] At present, the trolley furnace heats up in one stage, and there is no intermediate temperature buffer area during the temperature rise, resulting in a large deviation of the target temperature, causing the local temperature of the steel plate to be too high, and a long holding time is required to uniform the furnace temperature

There is no specific specification for the steel loading method of the trolley furnace, and insufficient attention has been paid to the production. The unscientific steel loading method is not conducive to the hot air circulation in the furnace, and it is difficult to control the uniformity of the furnace temperature.

After the heat preservation is over, the thermocouple and the reversing fan are directly turned off, and natural cooling is adopted, which cannot guarantee the uniformity of temperature drop in each area of ​​the furnace

The above problems lead to low heating efficiency of the trolley furnace, poor temperature control accuracy, uneven quality of finished products, and low pass rate, which seriously restrict the production of high-quality mold steel

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