Method for improving microstructure uniformity of GH4169 disk forgings

Abstract

The invention belongs to the field of forging hot working, and in particular relates to a method for improving the microstructure uniformity of GH4169 disk forgings. The method can realize forming bymeans of two-heating-number forging. The method comprises the steps that the mold cavity of an upper die is M-shaped, and the mold cavity of a lower die is W-shaped; a die and a finish forging die ensure that the minimum equivalent strain in the finish forging process is not less than 0.25; billets are made by die forging, the forging temperature is controlled at 980-1020 DEG C, the forging rate is controlled in 1-20mm / s, and the die heating temperature is controlled at 300-500 DEG C; surface defects such as oxide scale and forging cracks on prefabricated billets are removed by a sand blowingand grinding method; and finally, finish forging forming of the disk forgings is carried out, the forging temperature is controlled at 990-1010 DEG C, the forging rate is controlled in 0.5-5mm / s, andthe die heating temperature is larger than or equal to 350 DEG C. The method can effectively improve the microstructure uniformity of the GH4169 disk forgings, and further improve the consistency of the performances of different parts of the forgings.

Description

technical field [0001] The invention belongs to the field of forging thermal processing, and in particular relates to a method for improving the uniformity of the structure of a GH4169 disk forging. Background technique [0002] my country's advanced aero-engines use a large number of GH4169 alloys to manufacture key rotating discs such as compressor discs and turbine discs. The quality of the alloy disc forgings determines the safety of aero-engines to a certain extent. The microstructure of GH4169 alloy is very sensitive to the thermal processing process, and improper process control can easily lead to uneven microstructures such as mixed grains and coarse grains, which in turn affect the comprehensive performance of forgings. The current forging process of GH4169 disc forgings is usually manufactured by upsetting cake + die forging. In the upsetting cake process, the upper and lower flat dies are used to vertically compress the cylindrical bar. Due to the friction between...

AI Technical Summary

Problems solved by technology

The microstructure of GH4169 alloy is very sensitive to the thermal processing process. Improper process control can easily lead to uneven microstructures such as mixed grains and coarse grains, which will affect the overall performance of forgings.

The current forging process of GH4169 disc forgings is usually manufactured by upsetting cake + die forging. In the upsetting cake process, the upper and lower flat dies are used to vertically compress the cylindrical bar. Due to the friction between the upper and lower surfaces of the bar, the entire bar is deformed during compression. There is a very large difference in the deformation amount of each part, resulting in a dead zone of deformation on the upper and lower end faces or a small deformation zone and a large deformation zone in the center. The recrystallization degree of each part is very different, which leads to uneven structure of the preform. The uniform structure is further inherited into the forging, resulting in the uneven structure of the forging

To solve this problem, the domestic method usually used is to machine the billet after upsetting the cake, and adjust the deformation of each part of the forging during the die forging process. For disc forgings with large differences in plate and disc edge thickness, this method is difficult to apply. In addition, changing the shape of the blank through machining increases the machining man-hours, and at the same time increases the loss of materials, resulting in an increase in manufacturing costs; in order to improve the GH4169 alloy disc forging The uniformity of the overall structure, the hot die forging and isothermal forging forming methods have also been developed in China. The increase of the mold temperature can reduce the temperature drop during the forging process of the forging, promote lubrication, and improve the metal fluidity, but it still cannot change the upsetting cake. The problem of uneven deformation, and because the mold needs a long time to preheat, the manufacturing cycle is prolonged and the manufacturing cost is increased

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