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A technology for preparing heat treatment and heat treatment equipment, which is applied in the field of heat treatment of metal materials, can solve the problems of large floor space, difficulty, and high cost of isothermal normalizing production lines, and achieve the effects of reducing floor space, reducing technical difficulty, and saving production costs
Pending Publication Date: 2022-07-22
CHONGQING CHANGZHENG HEAVY IND
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The hardenability of 17CrNiMo6 steel is good. After preparatory heat treatment by conventional normalizing + tempering, there will be many quality defects. For example, there is bainite in the structure of 17CrNiMo6 steel, and the hardness value of 17CrNiMo6 steel is higher than 220HBW , resulting in large differences in microstructure and hardness between different parts or different positions of the same part, resulting in deterioration of cutting performance and increased heat treatment deformation, thereby reducing the accuracy level and performance of 17CrNiMo6 steel, which cannot meet the production specification requirements of 17CrNiMo6
[0003] In order to meet the preparatory heat treatment technical requirements of 17CrNiMo6, in the preparatory heat treatment process of 17CrNiMo6 materials, the isothermal normalizing process is used in the isothermal normalizing line (equipment) to carry out 17CrNiMo6 preparatory heat treatment, although it can improve the 17CrNiMo6 preparatory heat treatment to a certain extent. Quality, so that the treated 17CrNiMo6 meets the quality requirements, but there are still some problems, such as high cost of isothermal normalizing production line, large floor area, difficult control of process setting parameters, especially in the middle cooling stage for furnace loading and rapid cooling. 1. It is very difficult to precisely control the rapid cooling time, which leads to the fact that the general factory is not equipped with this production line, which brings great difficulty to the preparatory heat treatment of 17CrNiMo6 materials
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Embodiment 1
[0033] The example is basically as attached figure 1 Shown: a 17CrNiMo6 material preparatory heat treatment method, comprising the following steps:
[0034] Step S1, prepare the 17CrNiMo6 material to be heat treated and the heat treatment equipment, adjust the parameters of the heat treatment equipment, install the parts to be processed on the heat treatment equipment, and control the single processing capacity of the parts to be no greater than the maximum loading capacity of the heat treatment equipment;
[0035] Step S2, the temperature in the heat treatment equipment is raised to within the first preset temperature range at the first preset heating speed, after the temperature rise is completed, the heat preservation for a preset time is performed, and the heating equipment is stopped after the heat preservation time reaches the process heat preservation time, and the heat treatment is turned off. Equipment heating source, fully open the switch door of the heat treatment e...
Embodiment 2
[0055] This embodiment is basically the same as the first embodiment, the difference is that a circulating fan, specifically a blower, is fixedly installed inside the trolley furnace.
[0056] The specific implementation process of this embodiment is basically the same as that of the first embodiment, and the difference is:
[0057] The second step is to open the natural gas valve of the trolley furnace, and raise the temperature in the trolley furnace to 950 ℃ at 180 ℃ / h. The temperature in the trolley furnace of the valve console is kept at 950 °C for 45 minutes. During the heating and heat preservation period, the power of the blower is turned on synchronously, so that the blower can stir the heat in the trolley furnace.
[0058] The third step, after the holding time reaches 45min, close the natural gas valve to stop heating the trolley furnace, turn off the power supply of the blower, fully open the furnace door of the trolley furnace, and completely open the heated parts...
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Abstract
The invention relates to the technical field of metal material heat treatment, and discloses a 17CrNiMo6 material preheat treatment method, which comprises the following steps: heating a 17CrNiMo6 material, pulling out the heated 17CrNiMo6 material along with heat treatment equipment, cooling, returning a part into the heat treatment equipment again when the 17CrNiMo6 material is cooled to a certain temperature range, and equalizing the temperature of the part by utilizing the temperature difference between the inside and the outside of the part, and then the 17CrNiMo6 material is pulled out together with the heat treatment equipment to be cooled and returns to the equipment again to be subjected to temperature equalization after being cooled, cooling and temperature equalization are conducted repeatedly, the temperature of the 17CrNiMo6 material is controlled to be changed evenly, and the internal structure of the 17CrNiMo6 material is controlled to be changed evenly. Heating the 17CrNiMo6 material to a certain temperature range again after multiple times of cooling and temperature equalization, and then preserving heat for a certain period of time; and finally, taking out the 17CrNiMo6 material and naturally cooling the 17CrNiMo6 material in air. The method has the beneficial effects that the heat treatment technical difficulty of the 17CrNiMo6 material is reduced, the production cost of the 17CrNiMo6 material is saved, and the heat treatment efficiency and quality of the 17CrNiMo6 material are improved.
Description
technical field [0001] The invention relates to the technical field of heat treatment of metal materials, in particular to a preparatory heat treatment method for 17CrNiMo6 materials. Background technique [0002] At present, the key parts of high-power fans and internal combustion engines, such as gears, input / output shafts, etc., are made of 17CrNiMo6, which is a low-carbon alloy carburized steel. Machining is critical. The normalized structure of such forgings is required to be ferrite and pearlite, the hardness value is 160-200HBW, and the grain size is greater than or equal to 5. The hardenability of 17CrNiMo6 steel is good. After the conventional normalizing + tempering method is used for preparatory heat treatment, there will be many quality defects, such as bainite in the structure of 17CrNiMo6 steel, and the hardness value of 17CrNiMo6 steel is higher than 220HBW , resulting in large differences in the structure and hardness of different parts or at different posi...
Claims
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Application Information
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