Petrochemical forging is an important part of petrochemical equipment, its quality and performance have an important impact on the safety and efficiency of petrochemical production. However, in the manufacturing process of forgings, there are often residual austenite problems, which will have adverse effects on the mechanical properties and corrosion resistance of forgings. Therefore, the research and application of residual austenite elimination method is of great significance for improving the quality and performance of petrochemical forgings.
Residual austenite refers to the austenite structure that has not been completely transformed into martensite during the cooling process of the forging. Its presence will have the following adverse effects on the mechanical properties and corrosion resistance of forgings:
Reduced strength and hardness: The presence of residual austenitic structures can lead to reduced strength and hardness of forgings, which affects their carrying capacity and service life.
Reduce toughness: The presence of residual austenitic structure will reduce the toughness of the forging, making it prone to cracks and brittle fractures.
Reduced corrosion resistance: The presence of residual austenitic structures reduces the corrosion resistance of forgings, making them vulnerable to chemical and electrochemical corrosion.
In order to solve the problem of residual austenite in petrochemical forgings, the following methods can be adopted to eliminate:
Quenching and tempering treatment: Through quenching and tempering treatment, the residual austenite tissue can be decomposed and transformed, thereby reducing its amount. During the quenching process, the appropriate quenching medium and quenching temperature should be selected to ensure that the austenite can be completely transformed into martensite. In the tempering process, the appropriate tempering temperature and tempering time should be selected to ensure the stability and refinement of martensite.
Cryogenic treatment: Cryogenic treatment is a method of eliminating residual austenite by cooling the forgings to extremely low temperatures. During the cryogenic treatment process, the residual austenitic tissue in the forgings will undergo martensitic transformation, thereby reducing its amount. Cryogenic treatment can choose liquid nitrogen as the cooling medium, but attention needs to be paid to controlling the cooling speed and temperature to avoid cracks in the forging.
Mechanical treatment: Mechanical treatment is a method of removing residual austenite by mechanical force. For example, through mechanical treatment methods such as shot peening and rolling, compressive stress can be introduced on the forging surface to promote the transformation of residual austenite. This method requires attention to select the appropriate mechanical treatment and processing parameters to avoid damage to the forging.
Chemical treatment: Chemical treatment is a method of removing residual austenite by chemical methods. For example, through chemical treatment methods such as carburizing and nitriding, elements such as carbon and nitrogen can be introduced on the surface of the forgings to promote the transformation of residual austenite. This method requires attention to the selection of appropriate chemical treatment methods and processing parameters to ensure the treatment effect and forging quality.
In order to evaluate the effectiveness of residual austenite elimination methods, the following methods can be used for detection and evaluation:
Metallographic inspection: The microstructure of the forgings and the distribution of residual austenite can be observed through metallographic inspection to evaluate the effect of the elimination method.
Hardness testing: The hardness testing can evaluate the hardness and strength changes of the forging, so as to judge the effect of the elimination method.
Corrosion resistance test: The corrosion resistance test can evaluate the change of the corrosion resistance of the forging, so as to judge the effect of the elimination method.
The method of eliminating residual austenite in petrochemical forgings is one of the important measures to improve the quality and performance of forgings. In practical application, the appropriate elimination method should be selected according to the specific situation and requirements of forging, and the effect evaluation and optimization. In the future, with the continuous progress of science and technology and the improvement of green manufacturing requirements, we expect more efficient and environmentally friendly residual austenite elimination methods to be developed and provide a strong guarantee for the sustainable development of the petrochemical industry.
