A heat treatment method for QCr0.8 copper alloy

Abstract

This invention discloses a heat treatment method for QCr0.8 copper alloy, comprising: vacuum solution treatment, cold treatment, and vacuum aging treatment of QCr0.8 copper alloy; the heat treatment method of this invention enables the finished QCr0.8 parts to obtain the required mechanical properties after finishing, and compared with traditional processes, it effectively improves the comprehensive mechanical properties and surface quality, resulting in significant economic benefits.

Description

Technical Field

[0001] This invention belongs to the field of copper alloy heat treatment technology, specifically relating to a heat treatment method for copper-based alloy QCr0.8, which can improve the comprehensive mechanical properties of copper-based alloy QCr0.8. Background Technology

[0002] Copper and copper alloys are widely used in fields such as power, electronics, communications, chemical industry, machinery, transportation, marine engineering, aerospace, and petrochemicals due to their excellent electrical and thermal conductivity and corrosion resistance. They are the third most widely used metal after iron and aluminum.

[0003] Chromium bronze QCr0.8 is a copper-based alloy with chromium as the main strengthening element. Due to its excellent electrical and thermal conductivity, good plasticity, high-temperature mechanical properties, weldability, fatigue performance, and corrosion resistance, it is widely used in power, electrical engineering, aerospace, and other fields. Currently, annealing is a common heat treatment process for QCr0.8 in engineering applications. However, annealed QCr0.8 often exhibits lower mechanical properties, failing to meet application requirements. Therefore, a heat treatment technology specifically designed to improve the mechanical properties of QCr0.8 alloy is needed. Summary of the Invention

[0004] The purpose of this invention is to overcome the aforementioned defects and provide a heat treatment method for QCr0.8 copper alloy, solving the technical problem that existing annealed QCr0.8 often exhibits low mechanical properties and fails to meet application requirements. This invention employs a heat treatment method that enables the QCr0.8 alloy to achieve the desired properties. Compared with previous processes, this effectively improves production efficiency, meets production needs, and offers significant economic benefits.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: A heat treatment method for QCr0.8 copper alloy, comprising: The QCr0.8 copper alloy was subjected to solution treatment, cold treatment, and aging treatment. The cold treatment process involves holding the temperature at -70 to -80℃ for 90 to 100 hours followed by air cooling.

[0006] Furthermore, the solution heat treatment process involves heating to 900-915℃ within 90-100 minutes, holding at 900-915℃ for 60-180 minutes, and then air cooling.

[0007] Furthermore, the solution heat treatment process is carried out in a vacuum heat treatment furnace, with a vacuum degree ≤1.33×10⁻⁶. -2 Pa.

[0008] Furthermore, in the solution heat treatment process, the gas cooling charging pressure is 1~2 bar.

[0009] Furthermore, the aging heat treatment process involves heating to 400-418℃ within 50-60 minutes, holding at 400-418℃ for 120-180 minutes, and then air cooling.

[0010] Furthermore, the aging heat treatment is carried out in a vacuum heat treatment furnace, with a vacuum degree ≤1.33×10⁻⁶. - 2 Pa.

[0011] Furthermore, during aging heat treatment, the air cooling pressure is 1~2 bar.

[0012] This application discloses a heat treatment method for QCr0.8 copper alloy, relating to the field of heat treatment. The heat treatment method includes improving the comprehensive mechanical properties of the QCr0.8 alloy through solution treatment, cold treatment, and aging heat treatment. Specifically, the method includes: firstly, performing solution heat treatment using a vacuum heat treatment furnace at a vacuum degree ≤1.33×10⁻⁶. -2 Solution treatment was performed in a vacuum environment at 1-2 bar, followed by heating to 900-915℃ for 90-100 min, holding at that temperature for 60-180 min, and then cooling with gas at a pressure of 1-2 bar. After solution treatment, a cold treatment process was conducted, involving holding at -70-80℃ for 90-100 h followed by air cooling to room temperature. Following the cold treatment, an aging heat treatment was performed using a vacuum heat treatment furnace at a vacuum level ≤1.33 × 10⁻⁶. -2 Aging is performed in a vacuum environment of 1-2 bar, with the temperature increased to 400-418°C for 50-60 minutes, held for 120-180 minutes, and then cooled by gas filling at a pressure of 1-2 bar. This invention can effectively improve the mechanical properties of QCr0.8 alloy.

[0013] Compared with the prior art, the present invention has at least one of the following advantages: (1) The present invention provides a heat treatment method for QCr0.8 copper alloy. Through solid solution heat treatment, the solubility of Cr element in the alloy can be increased, and a supersaturated solid solution can be formed in the copper matrix. Then, the supersaturated solid solution can be stabilized at room temperature by rapid cooling. (2) The present invention heats the material to the uniform precipitation temperature of Cr by aging heat treatment, thereby producing aging desolvation, which strengthens the uniform distribution of the precipitated solute atoms Cr in the matrix and can significantly improve the strength of the material by hindering the movement of dislocations. (3) Through cold treatment, the present invention can induce phenomena such as grain rotation, dislocation movement and stress concentration in QCr0.8, which can promote grain boundary and grain breakage, thereby refining the grains and improving the strength; (4) The vacuum heat treatment and cold treatment in this invention do not affect the surface quality of QCr0.8 and can be used for QCr0.8 finished parts. Attached Figure Description

[0014] Figure 1 Microstructure of QCr0.8 alloy after heat treatment in Example 1; (a) OM; (b, c, d) SEM images at different locations; Figure 2 Microstructure of QCr0.8 alloy after heat treatment in Example 2; (a) OM; (b, c, d) SEM images at different locations; Figure 3 Microstructure of heat-treated QCr0.8 alloy (Comparative Example 1); (a) OM; (b, c, d) SEM images at different locations. Detailed Implementation

[0015] The features and advantages of the present invention will become clearer and more apparent from the following detailed description.

[0016] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments. Although various aspects of embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated otherwise.

[0017] The present invention discloses a heat treatment method for QCr0.8 alloy, which includes: solution treatment, cold treatment and aging treatment of QCr0.8 alloy to effectively improve the strength of the material.

[0018] In one specific embodiment, the solution heat treatment regime of the QCr0.8 alloy is 900~915℃ for 60~180 min followed by air cooling.

[0019] In one specific embodiment, the solution heat treatment of QCr0.8 alloy is carried out in a vacuum heat treatment furnace, with a vacuum level ≤1.33×10⁻⁶. -2 Pa.

[0020] In one specific embodiment, the QCr0.8 alloy undergoes a solution heat treatment process, with the temperature increased to 900-915℃ over 90-100 minutes.

[0021] In one specific implementation, the gas cooling charge pressure of the QCr0.8 alloy solution heat treatment process is 1~2 bar.

[0022] In one specific implementation, the cold treatment regime for QCr0.8 alloy is to hold at -70~-80℃ for 90~100 h followed by air cooling.

[0023] In one specific embodiment, the aging heat treatment regime for QCr0.8 alloy is 400~418℃ for 120~180 min followed by air cooling.

[0024] In one specific embodiment, the aging heat treatment of QCr0.8 alloy is carried out in a vacuum heat treatment furnace, with a vacuum level ≤1.33×10⁻⁶. -2 Pa.

[0025] In one specific embodiment, the QCr0.8 alloy undergoes an aging heat treatment process of 50-60 min, with the temperature increased to 400-418℃.

[0026] In one specific implementation, the air-cooled charging pressure of the QCr0.8 alloy aging heat treatment process is 1~2 bar.

[0027] Example: This invention provides a method for improving the comprehensive mechanical properties of the copper-based alloy QCr0.8, comprising: By subjecting QCr0.8 alloy to solution treatment, cold treatment, and aging heat treatment, a material with comprehensive properties superior to that obtained by annealing is obtained. The solution heat treatment atmosphere for the QCr0.8 alloy is a vacuum. The vacuum degree required for the solution heat treatment of the QCr0.8 alloy is less than or equal to 1.33 × 10⁻⁶. -2 Pa; The QCr0.8 alloy was subjected to solution heat treatment, with the temperature increased to 900~915℃ in 90 min and held for 60~180 min. After the QCr0.8 alloy underwent solution heat treatment and heat preservation, it was purged and cooled to room temperature at a pressure of 1~2 bar. The QCr0.8 alloy is subjected to cold treatment after solution heat treatment; The QCr0.8 alloy was cold-treated at -70℃ for 100 h. The QCr0.8 alloy was air-cooled to room temperature after the cold treatment and heat preservation process was completed. The QCr0.8 alloy is subjected to aging heat treatment after cold treatment; The aging heat treatment atmosphere for the QCr0.8 alloy is a vacuum. The vacuum degree required for the aging heat treatment of the QCr0.8 alloy is less than or equal to 1.33 × 10⁻⁶. -2 Pa; The QCr0.8 alloy is subjected to aging heat treatment, with the temperature increased to 400~418℃ in 50 min and held for 120~180 min. After the QCr0.8 alloy undergoes aging heat treatment and heat preservation, it is purged and cooled to room temperature at a pressure of 1~2 bar.

[0028] This invention provides a heat treatment process for QCr0.8 alloy, resulting in improved mechanical properties of QCr0.8 alloy after heat treatment, achieving a 100% pass rate for the first heat treatment of QCr0.8 alloy.

[0029] Example 1 A heat treatment method for QCr0.8 alloy specifically includes the following steps: A QCr0.8 test bar with a specification of Φ30×300 mm was selected as the test piece. Before heat treatment, the shape, size and surface quality of the test piece were checked. No bumps or cracks were allowed. The QCr0.8 test piece was placed in a vacuum heat treatment furnace for solution heat treatment, with a vacuum degree less than or equal to 1.33 × 10⁻⁶. - 2 Pa, the regime is to heat to 900℃ in 90 min, hold for 60 min, and after holding, pressurize and cool to room temperature, with a pressurization pressure of 1~2 bar; After solution heat treatment, the QCr0.8 test piece was buried in dry ice and compacted, and then kept for 100 h for cold treatment. After the cold treatment, it was air-cooled to room temperature. The cold-treated QCr0.8 test piece was placed in a vacuum heat treatment furnace for aging heat treatment, with a vacuum degree less than or equal to 1.33 × 10⁻⁶. -2 The pressure is 1-2 bar. The temperature is increased to 400-418℃ in 50 minutes, held for 180 minutes, and then inflated and cooled to room temperature after the holding period.

[0030] In this embodiment, the microstructure of the QCr0.8 material after treatment was observed. Figure 1 As shown in Table 1, the mechanical properties of the QCr0.8 material after treatment in this embodiment were measured.

[0031] Table 1 Mechanical properties of QCr0.8 alloy in Example 1 Example 2 A heat treatment method for QCr0.8 alloy specifically includes the following steps: A QCr0.8 test bar with a specification of Φ30×300 mm was selected as the test piece. Before heat treatment, the shape, size and surface quality of the test piece were checked. No bumps or cracks were allowed. The QCr0.8 test piece was placed in a vacuum heat treatment furnace for solution heat treatment, with a vacuum degree less than or equal to 1.33 × 10⁻⁶. - 2 Pa, the regime is to heat to 915℃ in 90 min, hold for 90 min, and after holding, pressurize and cool to room temperature, with a pressurization pressure of 1~2 bar; After solution heat treatment, the QCr0.8 test piece was buried in dry ice and compacted, and then kept for 100 h for cold treatment. After the cold treatment, it was air-cooled to room temperature. The cold-treated QCr0.8 test piece was placed in a vacuum heat treatment furnace for aging heat treatment, with a vacuum degree less than or equal to 1.33 × 10⁻⁶. -2 The pressure is 1-2 bar. The temperature is increased to 400-418℃ in 50 minutes, held for 120 minutes, and then inflated and cooled to room temperature after the holding period.

[0032] In this embodiment, the microstructure of the QCr0.8 material after treatment was observed. Figure 2 As shown in Table 2, the mechanical properties of the QCr0.8 material after treatment in this embodiment were measured.

[0033] Table 2 Mechanical properties of QCr0.8 alloy in Example 2 Comparative Example 1 A heat treatment method for QCr0.8 alloy specifically includes the following steps: A QCr0.8 test bar with a specification of Φ30×300 mm was selected as the test piece. Before heat treatment, the shape, size and surface quality of the test piece were checked. No bumps or cracks were allowed. The QCr0.8 test piece was placed in an air heat treatment furnace for annealing heat treatment at a temperature of 500℃ for 240 min. After the heat treatment, it was air-cooled to room temperature. The microstructure of the QCr0.8 material after the comparative treatment was observed, such as... Figure 3 As shown in Table 3, the mechanical properties of the QCr0.8 material after the comparative example treatment are measured.

[0034] Table 3 Mechanical properties of QCr0.8 alloy (Comparative Example 1) Comparison reveals that, compared to Comparative Example 1, Examples 1 and 2, by changing the original annealing heat treatment to solution treatment, cold treatment, and aging heat treatment, show a significant improvement in mechanical properties. This is because the improved performance of the QCr0.8 alloy is due to the solution heat treatment, which allows the strengthening phase to fully dissolve, forming a uniform supersaturated solid solution, laying the foundation for subsequent precipitation strengthening. Cold treatment causes the matrix to shrink, increasing the lattice distortion energy and promoting the diffusion of supersaturated atoms, providing heterogeneous nucleation sites for subsequent aging and significantly refining the size of the precipitated phases. The final aging heat treatment, occurring near the peak precipitation temperature of the strengthening phase, ensures uniform precipitation of the strengthening phase, which is dispersed throughout the matrix, significantly improving strength. The most significant difference between Examples 1 and 2 is that Example 2 shortens the aging time. While this improves production efficiency, insufficient aging reduces the precipitation of the strengthening phase. Simultaneously, the extended solution temperature and time result in coarse grains, thus reducing overall strength. However, comparing Example 2 with Comparative Example 1, it can be found that under room temperature conditions, the tensile strength of Example 2 is still significantly better than that of Comparative Example 1. At the same time, the production time is shortened compared with Example 1. Therefore, in actual production, the heat treatment system can be selected according to the needs.

[0035] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

[0036] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A heat treatment method for QCr0.8 copper alloy, characterized in that, include: The QCr0.8 copper alloy was subjected to solution treatment, cold treatment, and aging treatment. The cold treatment process involves holding the temperature at -70 to -80℃ for 90 to 100 hours followed by air cooling.

2. The heat treatment method for QCr0.8 copper alloy according to claim 1, characterized in that, The solution heat treatment process involves heating to 900-915℃ within 90-100 minutes, holding at 900-915℃ for 60-180 minutes, and then air cooling.

3. The heat treatment method for QCr0.8 copper alloy according to claim 1, characterized in that, The solution heat treatment process was carried out in a vacuum heat treatment furnace, with a vacuum level ≤1.33×10⁻⁶. -2 Pa.

4. The heat treatment method for QCr0.8 copper alloy according to claim 2, characterized in that, In the solution heat treatment process, the gas cooling charging pressure is 1~2 bar.

5. The heat treatment method for QCr0.8 copper alloy according to claim 1, characterized in that, The aging heat treatment process involves heating to 400-418℃ within 50-60 minutes, holding at 400-418℃ for 120-180 minutes, and then air cooling.

6. The heat treatment method for QCr0.8 copper alloy according to claim 1, characterized in that, The aging heat treatment is carried out in a vacuum heat treatment furnace, with a vacuum level ≤1.33×10⁻⁶. -2 Pa.

7. The heat treatment method for QCr0.8 copper alloy according to claim 5, characterized in that, During aging heat treatment, the air cooling pressure is 1~2 bar.

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