[0032] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described here are only used to illustrate and explain the present invention, and the present invention is not limited to the following specific embodiments.
[0033] figure 1 The brake beam preparation flow chart of an embodiment of the brake beam preparation method of the present invention, such as figure 1 As shown, the preparation method of the brake beam of the present invention may include:
[0034] S1, making and forming brake beam section steel;
[0035] S2, heating the brake beam section steel to a first preset temperature and maintaining the first preset temperature for a first preset time, where the first preset temperature is less than or equal to the phase transition temperature of the brake beam section steel material;
[0036] S3, further heating the brake beam section steel to a second preset temperature and maintaining it at the second preset temperature for a second preset time, where the second preset temperature is less than or equal to the brake beam section steel material and the Widmanite structure appears temperature;
[0037] S4, forging the brake beam section steel to form the brake beam;
[0038] S5: Put the brake beam into a cooling box and cool it to 280°C-320°C at a rate of less than or equal to 0.25°C/s, then remove it, and cool to normal temperature at room temperature.
[0039] Specifically, the method of manufacturing the brake beam section steel in step S1 may be a rolling method or a machining method, which is not specifically limited in the present invention. The steel used for the brake beam can be low-alloy high-strength steel Q460E.
[0040] In the process of heating the brake beam section steel to the first preset temperature and maintaining the first preset temperature for the first preset time, both the surface and the core of the brake beam section steel reach the first preset temperature. The first preset temperature is below the phase transition temperature of the material used for the brake beam section steel. And preferably, step S2 may specifically include: using an intermediate frequency induction heating device to heat the brake beam section steel at the first frequency, so that the surface and core of the brake beam section steel reach a phase transition temperature of 850°C or less for the brake beam section steel. The first preset temperature. The first frequency is 1KHz-4KHz, and the power output is 85%, so that the overall temperature (surface and core) of the brake beam section steel reaches the first preset temperature of 730℃-770℃, that is, the first heating is slow and long. Time heating method.
[0041] After completing step S2, the entire brake beam section steel is already above the first preset temperature. At this time, step S3 can be further implemented, that is, to continue heating the brake beam section steel to the second preset temperature and at the second preset temperature. Maintain the second preset time, where the second preset temperature is less than or equal to the temperature at which the Widmanite structure of the brake beam section steel material appears, so as to avoid the generation of coarse-grained Widmanite structure to improve the mechanical properties of the brake beam. Especially improve the impact performance of the brake beam.
[0042] Wherein, step S3 preferably adopts rapid heating, which may specifically be: using the intermediate frequency induction heating device to heat the brake beam section steel at a second frequency so that the brake beam section steel reaches a temperature less than or equal to a second preset temperature. The frequency of the intermediate frequency induction heating device can be, for example, 1KHz-20KHz, and the total power of the intermediate frequency induction heating device can be, for example, 450KW. The second preset temperature may be 960°C-1000°C, and an appropriate second preset time may be selected according to the second preset temperature value to avoid the generation of Widmanite, thereby preventing the impact performance of the brake beam from being affected.
[0043] After the second heating in step S3, the brake beam section steel can be forged to form the brake beam. Specifically, the heated brake beam section steel is cut, stretched, bent and shaped to form a brake beam with a preset size. In the process of slitting, stretching, bending and shaping, the heated brake beam is naturally cooled in the air, that is, normalized at the forging station to remove part of the internal stress of the material, increase the hardness of the material, and make the crystal Grain refinement.
[0044] After the brake beam is formed by mechanical processing, the brake beam can be placed in a cooling box and cooled to 280°C-320°C at a rate of less than or equal to 0.25°C/s, then removed, and cooled to normal temperature at room temperature. It is cooled in the cooling box to remove the residual stress in the forging process, ensure the external dimensions of the brake beam, and ensure the mechanical performance index of the brake beam, especially the impact energy of the brake beam. After cooling to 280°C-320°C in the cooling box, the size and structure of the brake beam have been shaped. Remove the cooling box and continue to cool to room temperature at room temperature, which improves the utilization efficiency of the cooling box and speeds up production.
[0045] In the preparation method of the brake beam in this embodiment, the brake beam section steel is subjected to two-stage heating treatment. The first section uses intermediate frequency induction heating equipment to heat the brake beam section steel at a frequency of 1KHz-4KHz for 100s-120s so that the surface and the core of the brake beam section Reach 730℃-770℃; The second stage uses intermediate frequency induction heating equipment to heat at a frequency of 10KHz-20KHz for 20s-40s so that the temperature of the brake beam section steel reaches the second preset temperature of 960℃-1000℃ to avoid unfavorable metallography After forging to form a brake beam and normalizing by forging waste heat, the brake beam is cooled in a cooling box, cooled to 280℃-320℃, and removed, and cooled to normal temperature at room temperature to make the brake beam not Air-cooling and tempering treatment is carried out to further avoid the appearance of coarse grain structure and ensure the impact performance of the brake beam; finally realize the control of the size of the brake beam, so that the processed brake beam can meet the requirements of the brake beam The performance index requirements ensure the dimensional qualification rate of the brake beam, and also improve the preparation efficiency of the brake beam.
[0046] Further, the above step S5 may specifically be: when the temperature of the brake beam is greater than or equal to 600° C., the brake beam is placed in a cooling box for cooling, so as to effectively ensure the impact performance of the brake beam.
[0047] In the foregoing embodiment, the first frequency heating and the second frequency heating are produced in a single cycle, ensuring that each brake beam has consistent heating and cooling conditions, and avoiding the heating of the brake beam section steel of the furnace heating before and after the furnace. The problem of inconsistent heat preservation time effectively guarantees the consistency of brake beam products.
[0048] Another embodiment of the present invention also provides a cooling box used in the brake beam preparation method described in any of the above embodiments. figure 2 It is a schematic diagram of the cooling box structure of the present invention. Such as figure 2 As shown, the cooling box includes a box body 1 and a guide rail 3. The box body 1 includes a top wall 11 and a first side wall 12, a second side wall 13 and a third side wall 14 connected to the top wall 11. The top wall 11 and the first A side wall 12, a second side wall 13 and a third side wall 14 jointly enclose a semi-closed accommodating space, wherein the bottoms of the two opposite first side walls 12 and the second side walls 13 are provided with grooves 15, and the grooves 15 is used to cooperate with the guide rail 3 so that the cooling box 1 moves along the guide rail 3 so as to wrap the brake beam cooling frame 2 in the semi-closed containing space. The forged brake beam is placed in the space 21 of the brake beam cooling frame 2, and the cooling box 1 is moved so that the brake beam cooling frame with the brake beam is contained in the semi-enclosed accommodating space of the cooling box 1. The top wall 11 , The first side wall 12, the second side wall 13 and the third side wall 14 are all provided with a thermal insulation layer, so that the brake beam is slowly cooled at a cooling rate lower than the air-cooling cooling speed to ensure the impact performance of the brake beam. Specifically, the top wall and side walls of the cooling box are metal plates, which can be steel or iron, which is not specifically limited in the present invention. The thermal insulation layer can be a high-temperature resistant calcium silicate shell or a high-temperature resistant ceramic fiber to achieve a good thermal insulation effect, while also being resistant to high temperatures without significant qualitative changes in a high-temperature environment.
[0049] After the inventor’s experiment, it is found that steel materials with different element contents are selected according to the element content standard of GB/T 1591-2008 low-alloy high-strength steel, and the brake beam preparation method of the present invention is used to process the brake beam, which can meet the requirements of manufacturing The performance index requirements of the moving beam. By adopting the air cooling and tempering process of the brake beam in the prior art, the outer dimension of the brake beam has changed greatly, and the dimensional qualification rate is only 70%. However, the size of the brake beam formed by the preparation method of the brake beam of the present invention The pass rate can reach at least 96%.
