A method for hot isostatic pressing net shaping of powder near molten state

Abstract

The invention discloses a powder near-molten state hot isostatic pressing net forming method. The method comprises the following steps that according to the requirements for the material, the performance and the structure of a component needing to be subjected to hot isostatic pressing forming, a hot isostatic pressing forming sheath material and a controlled-shape core material, and corresponding dies are designed and machined; a hot isostatic pressing forming die is assembled, and after powder is added in the hot isostatic pressing forming die and vibrated tightly, the hot isostatic pressing forming die is subjected to vacuum pumping and seal welding; and according to the character of the formed powder, the hot isostatic pressing technology is determined, the near-molten state of the powder under hot isostatic pressing forming is ensured, the hot isostatic pressing forming die is subjected to hot isostatic pressing forming treatment, the die is removed, a non-matched face is machined, and a needed product is obtained. The filling performance of the powder in the hot isostatic pressing process is greatly improved, and the low-density phenomenon of a complex structure, especially a narrow and long thin-wall structure in a traditional hot isostatic pressing forming method is avoided; and meanwhile, the near-molten state powder is formed under the action of high pressure, the hole loosing defect does not exist inside a component, and the comprehensive performance of the final product is improved.

Description

Technical field [0001] The present invention belongs to the field of hot isostatic pressing, and more specifically, relates to a method for net hot isostatic pressing of powder near molten state, which can avoid complex structures, especially long and narrow thin-walled structures, in traditional hot isostatic pressing methods. The phenomenon of low density, there are no holes and loose defects inside the parts, and the overall performance of the final parts is improved. Background technique [0002] The working blades, turbine discs, combustion chambers, missile intake cylinders and other key parts of aerospace engines have extremely strict requirements on materials. They not only require good high-temperature oxidation and corrosion resistance, but also require high high-temperature strength and creep resistance. Variable strength and good fatigue performance. Superalloys are widely used in the aerospace field because of their good comprehensive properties. Nickel-based alloy...

AI Technical Summary

Problems solved by technology

[0003] However, aerospace engine parts and missile parts have complex structures, and it is very difficult to form them compared to ordinary parts.

Traditional material forming methods such as casting, forging, machining, etc. have corresponding defects: casting has good overall formability and effectively improves material utilization, but due to serious segregation of parts, many parts with loose holes and poor mechanical properties, At the same time, the formability of thin-walled and complex large parts is average; die forging can effectively overcome the defects of poor casting performance, but due to the high deformation resistance of superalloys, expensive precision molds and high-power forging equipment are required, and the process is very difficult to control; Machining can form more complex part structures, but nickel-based superalloys have high hardness and are difficult to cut, and will waste a lot of precious alloy materials. It is difficult to form parts with the characteristics of complex structure, many arc transitions, etc.

[0005] The existing hot isostatic pressing technology utilizes the deformation of the sheath under the action of high temperature and high pressure to drive the powder inside the sheath to move, thereby densifying the parts. However, further research shows that most of the shape-controlling cores in the prior art are made of carbon steel materials, while carbon steel materials are prone to deformation under the action of high temperature and high pressure, and the shape control accuracy is poor. At the same time, due to the different rigidity of different positions of the sheath, the deformation under pressure is difficult to predict and control, and the deformation degree of different positions of the sheath There is a large difference, which leads to different densification degrees of the powder at different positions of the part driven by the sheath. Usually, in order to ensure the forming quality of the part and ensure that the global densification of the part is uniform, most of the traditional hot isostatic pressing will leave more This results in unnecessary waste of powder; and when using the traditional hot isostatic pressing process to form complex parts, often due to the complexity of the parts, the powder in key positions such as the corners of the parts and the narrow and long flow channels during the isostatic pressing process Due to the difficulty of flow, the mechanical properties of the key parts of the parts are reduced, and the overall performance of the hot isostatic pressing parts is reduced

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