A method for obtaining gh4169 alloy ultra-fine grain forging

Abstract

The invention discloses a method for obtaining a GH4169 alloy ultrafine-grained forging. The steps of the method are as follows: (1) the GH4169 forging billet is subjected to solution treatment and aging treatment successively to obtain a uniform structure containing a certain amount of delta phase; (2) The forging billet after solid solution and aging treatment is forged and deformed, the deformation temperature is controlled between 950°C and 1010°C, and the strain rate is not less than 0.05s ‑1 , the equivalent strain is not less than 0.35; (3) The obtained forging is subjected to aging treatment again, the aging temperature is controlled between 880°C and 920°C, and the aging time is 9h to 24h; (4) The forging is subjected to continuous cooling. For recrystallization heat treatment, the starting temperature of cooling is controlled between 990°C and 1030°C, the cooling rate is between 1°C / min and 3°C / min, and the ending temperature of cooling is controlled between 950°C and 990°C. The method proposed by the invention can obtain GH4169 alloy ultra-fine grain forgings, and provides an effective way for manufacturing high-quality forgings.

Description

technical field [0001] The invention relates to a method for obtaining GH4169 alloy ultra-fine grain forgings, which belongs to the technical field of forging. Background technique [0002] GH4169 alloy is a precipitation-strengthened nickel-based alloy, which has good comprehensive properties at -253°C to 650°C, high yield strength, good fatigue resistance, oxidation resistance, and corrosion resistance, so it is widely used in the manufacture of turbine disks and other high-quality aero-engine parts. These components have been in service for a long time under the harsh conditions of high temperature, high pressure, high speed and alternating load, so extremely high requirements are put forward for their performance. Grain refinement is an important way to improve the strength, plasticity and formability of parts. The key to obtaining a uniform and fine forging grain structure is to increase the recrystallization nucleation rate while reducing the grain growth rate. [0...

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Problems solved by technology

However, the technical solutions disclosed above still have the following problems: (1) Although the deformed mixed crystal structure can be uniformly refined to a certain extent through two annealing treatments, the structure is still not uniform and fine.

After the annealing treatment, the grain size of the alloy can only reach ASTM10 grade, and there are still relatively coarse grains in the structure, which makes the structure uneven; (2) The second annealing treatment adopts a constant temperature annealing process, and the process parameter window is narrow , process optimization is difficult

The annealing temperature must be strictly controlled at about 980°C to obtain a better grain refinement effect, and it is difficult to further optimize the process parameters to improve the uniform refinement of the structure

If the annealing temperature is higher, although the recrystallization nucleation rate can be increased, it is obviously also conducive to the growth of recrystallized grains and the rapid dissolution of the second phase, resulting in the formation of coarse grains.

However, when the annealing temperature is low, the recrystallization nucleation rate is insufficient, and the mixed crystal state of the alloy after hot deformation cannot be effectively improved.

In summary, although the two annealing processes mentioned in this method can refine the grains to a certain extent and improve the uniformity of the deformed mixed crystal structure, due to the constant temperature annealing process used in the second annealing process, it cannot be effectively passed. Process parameter optimization further increases the grain size of the alloy and improves the uniformity of the grain structure, it is difficult to obtain a uniform ultra-fine grain structure

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