As an important part of material processing, heat treatment plays a key role in the performance and service life of locomotive main and auxiliary connecting rod forging. In this paper, the application of heat treatment in forging of main and auxiliary connecting rod of locomotive is discussed.
Heat treatment changes the internal structure of metal materials by controlling heating, insulation and cooling, so as to improve its mechanical properties, physical properties and chemical properties. Heat treatment is a key step to improve the strength, toughness and corrosion resistance of locomotive main and auxiliary link forging.
Application of heat treatment in forging of main and auxiliary connecting rod of locomotive
Preheating treatment: Preheating raw materials before forging helps to reduce the difficulty of forging, reduce the risk of cracking, and improve the formability of forgings.
Forging heating: In the forging process, the right heating temperature and heating time are crucial to ensure the quality of the forging. High temperature can improve the plasticity of the metal and facilitate forging, but too high temperature may cause the metal to overburn or reduce mechanical properties.
Solution treatment: By heating the connecting rod to a high temperature and holding it for a period of time, the alloying elements are fully dissolved into the matrix. This is followed by quenching, a rapid cooling that supersaturates the alloying elements in the matrix to improve strength and hardness.
Tempering treatment: Quenched links usually require tempering treatment to stabilize the structure, remove internal stress and improve toughness. According to the need, you can choose different tempering temperature and time.
Surface treatment: For some special purpose connecting rods, surface heat treatment may be required, such as carburizing, nitriding, etc., to improve the surface hardness and corrosion resistance.
Quality testing: The rod after heat treatment needs to undergo strict quality testing to ensure that its performance meets the requirements. It can be tested by metallographic microscope, hardness tester, tensile testing machine and other equipment.
Taking the heat treatment process of the main and auxiliary connecting rod forging of a certain type of locomotive as an example, the heat treatment process is analyzed in detail:
The forging is made of high strength alloy steel, first preheating treatment, preheating temperature is about 300℃, and heat preservation for a period of time to improve the plasticity of the material. During the forging process, the steel is heated to a suitable forging temperature (about 1200 ° C) and is cooled rapidly to maintain the desired shape and size. After forging is completed, solid solution treatment is carried out, heated to about 1050℃ and held for a period of time, so that the alloying elements are fully dissolved into the matrix. This is followed by a quenching process where the connecting rod is rapidly cooled to room temperature so that the alloying elements are supersaturated in the matrix. In order to stabilize the organization and improve toughness, tempering treatment is carried out, and the connecting rod is heated to about 550℃ and kept warm for a period of time. Finally, the surface treatment and quality control are carried out to ensure that the heat-treated connecting rod meets the performance indexes.
In this paper, the application of heat treatment in forging of main and auxiliary connecting rod of locomotive is deeply discussed, and the following conclusions and suggestions are drawn:
Strict control of heat treatment process parameters: appropriate heating temperature, holding time and cooling rate are the key to ensure the heat treatment effect. The heat treatment equipment should be checked and maintained regularly to ensure the accuracy of the process parameters.
Choose the right heat treatment method: for different materials and performance requirements, choose the right heat treatment method. For example, for high-strength alloy steel connecting rod, the hardness and toughness can be improved by quenching and tempering process.
Strengthen quality testing and control: the connecting rod after heat treatment should be strictly tested and controlled to ensure that its performance meets the requirements. The connecting rod can be tested by various testing means such as metallographic microscope, hardness tester, tensile test, etc.
Continuous improvement and innovation: pay attention to industry dynamics and new technology development, constantly optimize and improve the heat treatment process, improve the performance and service life of locomotive main and auxiliary connecting rod forgings. At the same time, strengthen exchanges and cooperation with domestic and foreign counterparts to jointly promote the development of heat treatment technology.