Nickel-based high temperature alloy forging parts, the heat treatment process introduction
Nickel-based high-temperature alloy forging parts have high strength, good toughness and oxidation resistance, and are widely used in aviation, shipbuilding, petrochemical, nuclear power, turbine, pressure vessel and other fields. Its important performance parameters and service characteristics are fully determined by the proper design of the heat treatment process. This article mainly introduces the heat treatment process of nickel-based high-temperature alloy forgings.
1. Heat treatment process
The heat treatment process of nickel-based high temperature alloy forging parts mainly includes annealing, normalizing, tempering, quenching and tempering, so as to obtain the desired structure and performance.
1.1 Annealing
Annealing can be heated to the austenitization temperature of 1050 ~ 1200℃, and then cooled at a suitable rate to obtain a single-phase austenitic structure. The purpose of annealing is to reduce the hardness of the parts, improve the dimensional accuracy and improve the process performance of the parts.
1.2 Normalizing
The normalizing heat treatment of nickel-based high-temperature alloy forged parts can be performed by air cooling after normalizing. The purpose of normalizing is to obtain a higher organization, make the structure more uniform, and improve the mechanical properties of the forged parts.
1.3 tempering
Tempering is the heat treatment of nickel-based high-temperature alloy forging parts after forming by heating to 550 ~ 725℃, soaking for a period of time and then cooling in still air or oil. The purpose of tempering is to refine the organization and improve the strength and ductility of the forged parts.
1.4 Quenching and tempering
The quenching and tempering heat treatment of nickel-based high-temperature alloy forgings is to heat the parts to the austenitizing temperature, and then quench to obtain a single austenitic structure. And then heat to about 500-650℃ for reheating and tempering treatment, so that it can obtain stable work performance.
2. Heat treatment process control
The heat treatment process of nickel-based high temperature alloy forging parts is an important process to obtain the desired structure and performance. In order to improve the performance and quality of the forging parts, it is necessary to control the heat treatment process in particular. If the heat treatment process is not controlled, it will not only reduce the performance of the forging parts, but also cause serious safety accidents due to poor quality of the forging parts.
2.1 Temperature control
In the heat treatment process of nickel-based high temperature alloy forging parts, the temperature control is particularly important. When the temperature is not qualified, the phase transformation of the forgings will be affected, thereby affecting the performance and quality of the forgings. Therefore, temperature control must be done during the heat treatment process.
2.2 cooling rate
In order to obtain the desired internal structure of nickel-based high temperature alloy forging parts, the cooling rate should be properly controlled during the heat treatment process, otherwise the performance of the parts will be affected. The cooling rate is usually different for different austenitizing temperatures and different parts.
2.3 Aging
The aging process of nickel-based high-temperature alloy forging parts is an important process to adjust the performance and structure of the forging parts. During the aging process, the aging temperature and holding time should be strictly controlled, otherwise the performance and quality of the forging parts may not meet the requirements.
3. Conclusion
Nickel-based high-temperature alloy forging parts have high strength, good toughness and oxidation resistance, and are widely used in aviation, shipbuilding, petrochemical, nuclear power, turbine and pressure vessel industries. The heat treatment process of nickel-based high temperature alloy forging parts is the most important process to obtain the desired product performance. According to the characteristics of nickel-based high-temperature alloy, the heat treatment process must pay attention to temperature control, cooling rate and aging temperature and time.
