Heat treatment process of GH4169 alloy material for CT machine spring

Abstract

The invention provides a heat treatment process of a GH4169 alloy material for a CT (Computed Tomography) machine spring, which is characterized by comprising the following steps of: (1) preparing the GH4169 alloy material meeting the GB / T 14992 standard, and carrying out solution treatment; (2) aging treatment is carried out for the first time, the alloy material subjected to solution treatment is heated to 700-720 DEG C along with a furnace at the heating rate of 10-20 DEG C / min, heat preservation is carried out for 7-9 h, and then furnace cooling is carried out to 600-620 DEG C at the rate of 50 DEG C / h; and (3) finally, carrying out secondary aging treatment, namely, on the basis of the primary aging treatment, carrying out furnace cooling to 600-620 DEG C at the speed of 50 DEG C / h, carrying out heat preservation for 7-9 hours, then rapidly cooling to room temperature along with the furnace, and taking out of the furnace. Aiming at the defects in the prior art, the invention provides the heat treatment process of the GH4169 alloy material for the CT machine spring, and the structure property of the GH4169 alloy material for the CT machine spring can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of heat treatment, and particularly to a heat treatment process for GH4169 alloy materials used in CT machine springs. Background Art

[0002] Due to its excellent comprehensive properties, such as good strength, toughness, fatigue resistance, and corrosion resistance, GH4169 alloy is widely used in the fields of aerospace and new energy. In the manufacturing of CT machine springs, strict requirements are imposed on the microstructure and properties of GH4169 alloy. The springs need to have a high elastic limit, fatigue resistance, and dimensional stability to ensure the accurate and reliable operation of CT machines during long-term operation.

[0003] There are certain limitations in the traditional heat treatment process of GH4169 alloy in meeting the special performance requirements of CT machine springs. Common problems include poor uniformity of the internal microstructure of the alloy, resulting in large dispersion of material properties; unsatisfactory size and distribution of precipitated phases, affecting the strength and fatigue resistance of the alloy; incomplete elimination of residual stress, which is likely to cause stress concentration during the service of the spring and reduce the service life of the spring. Therefore, it is of great practical significance to develop a new heat treatment process for GH4169 alloy materials used in CT machine springs to improve their microstructure and properties. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides a heat treatment process for GH4169 alloy materials used in CT machine springs, which can effectively improve the microstructure and properties of GH4169 alloy materials used in CT machine springs.

[0005] To achieve the above object, the present invention provides a heat treatment process for GH4169 alloy materials used in CT machine springs, including the following steps: (1) Prepare GH4169 alloy materials that meet the GB / T 14992 standard and perform solution treatment; (2) Heat the solution-treated GH4169 alloy materials in the furnace at a heating rate of 10 - 20 °C / min to 700 - 720 °C, hold for 7 - 9 h, and then cool in the furnace at a rate of 50 °C / h to 600 - 620 °C. The purpose of this step is to promote the uniform and fine precipitation of γ' and γ" strengthening phases and improve the alloy strength; (3) Finally, perform two aging treatments. Cool in the furnace at a rate of 50 °C / h to 600 - 620 °C, hold for 7 - 9 h, and then quickly cool in the furnace to room temperature and take out of the furnace. The purpose of this step is to further adjust the size and distribution of precipitated phases, optimize the alloy microstructure, and at the same time eliminate residual stress, improve the fatigue resistance and dimensional stability of the alloy.

[0006] Further setting: In the solution treatment of step (1), first heat up to 600 °C at a rate of 10 - 20 °C / min in a vacuum furnace, hold for 20 - 30 min, then heat up to 900 °C at a rate of 10 - 20 °C / min and hold for 20 - 30 min, and finally heat up to 1070 - 1090 °C at a rate of 10 - 20 °C / min, hold for 60 - 70 min and then cool with argon. The inflation pressure is 2 - 5 bar and the inflation time is 1000 - 1400 s. After air quenching, air cool to room temperature and take out of the furnace. The purpose of this step is to fully dissolve alloying elements in the matrix, lay a foundation for the uniform precipitation of subsequent precipitated phases, and at the same time rapidly cool to avoid grain growth.

[0007] The advantages of adopting the above technical solution are as follows: Through three key steps of solution treatment, primary aging treatment and secondary aging treatment, by precisely controlling parameters such as temperature, heating rate, cooling rate and holding time, the microstructure of the alloy is improved, its comprehensive mechanical properties are enhanced, the hardness of GH4169 alloy material can be increased, and the hardness dispersion can be improved. At the same time, the present invention can refine grains, eliminate twins, improve the tissue uniformity, and the structure after heat treatment is that γ' and γ" strengthening phases are uniformly and dispersedly distributed on the austenite matrix. Brief Description of the Drawings

[0008] Figure 1 is the heat treatment heating curve of the present invention; Figure 2 is the metallographic structure diagram of GH4169 alloy after heat treatment by traditional process; Figure 3 is the metallographic structure diagram of GH4169 alloy after heat treatment of the present invention; Detailed Embodiments

[0009] An embodiment of the heat treatment process of GH4169 alloy material for CT machine springs of the present invention is as Figures 1-3 shown: Take a GH4169 alloy material with a specification of 10 mm × 10 mm × 50 mm and meeting the GB / T 14992 standard. Its heat treatment steps are as follows: 1. Put the GH4169 alloy specimen into a vacuum heating furnace, heat up to 600 °C at a rate of 20 °C / min, hold for 30 min, then heat up to 900 °C at a rate of 20 °C / min and hold for 30 min, and finally heat up to 1080 °C at a rate of 20 °C / min, hold for 60 min and then cool with argon. The inflation pressure is 3 bar and the inflation time is 1200 s. After air quenching, air cool to room temperature and take out of the furnace.

[0010] 2. First, heat the solution-treated GH4169 alloy material in the furnace at a heating rate of 20 °C / min to 720 °C, hold for 8 h, and then cool in the furnace at a rate of 50 °C / h to 620 °C.

[0011] 3. On the basis of the first aging treatment, cool in the furnace at a rate of 50 °C / h to 620 °C, hold for 8 h, and then quickly cool in the furnace to room temperature and take out of the furnace.

[0012] An embodiment of the heat treatment process of the GH4169 alloy material for the CT machine spring in the present invention is as Figures 1-3 shown: 1. Put the GH4169 alloy specimen into a vacuum heating furnace, first heat it to 600 °C at a rate of 10 °C / min, hold for 30 min, then heat it to 900 °C at a rate of 10 °C / min and hold for 30 min, and finally heat it to 1070 °C at a rate of 10 °C / min. After holding for 60 min, cool it with argon. The inflation pressure is 3 bar, the inflation time is 1200 s, and after air quenching, air cool it to room temperature and take out of the furnace.

[0013] 2. First, heat the solution-treated GH4169 alloy material in the furnace at a heating rate of 10 °C / min to 700 °C, hold for 8 h, and then cool in the furnace at a rate of 50 °C / h to 600 °C.

[0014] 3. On the basis of the first aging treatment, cool in the furnace at a rate of 50 °C / h to 600 °C, hold for 8 h, and then quickly cool in the furnace to room temperature and take out of the furnace.

[0015] Finally, after testing, the hardness of the GH4169 alloy material treated by the present invention is 45 - 47 HRC, which is about 3 HRC higher than that of the traditional heat treatment process, and the hardness dispersion is greatly improved. At the same time, the present invention can refine grains and eliminate twins. Figure 3 This is the metallographic structure diagram of the GH4169 alloy after heat treatment in the present invention, and its structure is: γ' and γ" strengthening phases are evenly and dispersedly distributed on the austenite matrix, and the tissue uniformity is significantly improved.

[0016] The above examples are only one of the preferred specific examples of the present invention, and the common changes and substitutions made by those skilled in the art within the scope of the technical solution of the present invention are included in the protection scope of the present invention.

Claims

1. A heat treatment process for GH4169 alloy material used in the springs of a CT machine, characterized in that, It includes the following steps: (1) Prepare GH4169 alloy materials that meet the GB / T 14992 standard and conduct solution treatment; (2) Then conduct one aging treatment. Heat the alloy materials after solution treatment in the furnace at a heating rate of 10 - 20 °C / min to 700 - 720 °C, hold for 7 - 9 h, and then cool in the furnace to 600 - 620 °C at a rate of 50 °C / h; (3) Finally, conduct two aging treatments. The process is based on the first aging treatment, cool in the furnace to 600 - 620 °C at a rate of 50 °C / h, hold for 7 - 9 h, and then quickly cool in the furnace to room temperature and take out of the furnace.

2. The heat treatment process of the GH4169 alloy material for the CT machine spring according to claim 1, characterized in that: The heating rate in step (1) is 10 - 20 °C / min. First, heat to 600 °C, hold for 20 - 30 min, then heat to 900 °C at a rate of 10 - 20 °C / min and hold for 20 - 30 min. Finally, heat to 1070 - 1090 °C at a rate of 10 - 20 °C / min, hold for 60 - 70 min, and then cool with argon. The inflation pressure is 2 - 5 bar, the inflation time is 1000 - 1400 s, and after air quenching, air cool to room temperature and take out of the furnace.

Images