Study On Forging Technology And Microstructure And Properties Of Ventilated Forged Steel Brake Disc

The brake disc is an important component of the train brake system.It is related to the safe of railway transportation and plays a vital role in the development of rail transit.Its properties are affected by many factors,such as material,structure and forming process.In this thesis,the forging process,mechanical properties and metallographic structure of the ventilated shaft-mounted forged steel brake disc are studied.The main research contents and conclusions are as follows:(1)Hot upsetting test of low alloy steel for brake disc was carried out,and samples with different deformation were prepared.The mechanical properties and structure were analyzed.Combined with the simulation technology,the influence of different deformation on the microstructure and properties of low alloy steel for brake discs was investigated.It is found that the plastic toughness and microstructure of low alloy steel materials for brake discs are most affected by effective strain.(2)According to the structural characteristics of the brake disc,the brake disc die forging process design is completed.Through theoretical analysis and calculation,the structural elements such as the parting surface and the forging slope of the forging and the structure of the flashing groove are designed.The blank size required for the forming of the forging was calculated.And the press is selected according to the deformation force required to form the brake disc on the screw press.(3)The simulation process was used to simulate the process of forming the brake disc forging.The effects of blank size,fly-slot bridge height and initial forging temperature on the forming quality of forgings were investigated.The metal flow law,stress field,strain field,temperature field and load-displacement curve were analyzed.Finally,the brake disc blank size,mold structure and forging process parameters with good forming quality were obtained.(4)The brake disc forging test was completed under the guidance of the simulation results.The mechanical properties of different parts of the disc were tested after heat treatment.Metallographic structures and tensile fractures were also observed.The differences in strength,hardness and plastic toughness of different parts of the disc disk were studied.The performance of the disc body meets the requirements of the brake disc standard,and the material near the inner diameter of the disc body is in a three-way compressive stress state due to the formation,the structure is dense,and the elongation after impact and the impact energy are 30%higher than the outer edge portion of the disc.The research results of this thesis have important engineering guiding significance for the forging production process of ventilated forged steel brake discs.