Heat treatment method for GH99 alloy annular forgings

Abstract

The invention belongs to the technical field of heat treatment of high-temperature alloy forgings, and discloses a heat treatment method for GH99 alloy annular forgings, which comprises the following steps: heating the forged GH99 alloy forgings to 1100 DEG C, preserving heat for 1-3 hours, carrying out air cooling and precooling on the forgings for 1-5 minutes after discharging, and then carrying out water cooling. Compared with a conventional GH99 alloy heat treatment method, layered staggered placement is adopted for heat treatment charging of the annular forge piece, it is guaranteed that each face of the forge piece is cooled uniformly, the treated forge piece is uniform in structure, and the hardness of the surface and the core of the forge piece is uniform; according to the method, after solid solution heat preservation is finished, the cooling mode that air cooling and pre-cooling are conducted firstly, and then water cooling is conducted is adopted for cooling, so that the difference between the surface cooling rate and the core cooling rate of the forge piece is reduced, the hardness HB (d) of the treated forge piece is within the range of 3.6-3.9 mm, the strength surplus amount is large, and the delivery and use requirements are met.

Description

technical field [0001] The invention belongs to the technical field of heat treatment of high-temperature alloy forgings, and in particular relates to a heat treatment method for GH99 alloy ring forgings. Background technique [0002] GH99 alloy is an aging-strengthened nickel-based deformed superalloy. It is based on Ni and Cr, solid solution strengthening with W, Mo and Co, aging strengthening with Al and Ti, and grain boundary strengthening with B, Ce and Mg. The alloy material is mainly used for components such as combustion chambers, baffles, ribs and aircraft fixtures of aero-engines whose operating temperature does not exceed 1000°C. [0003] Ring forgings produced by GH99 alloy require forging hardness HB(d)≥3.51mm after solution treatment, and tensile strength requirements ≥930MPa. After conventional heat treatment, forging surface hardness HB(d)3.51mm~3.9mm often occurs, If the hardness of the corresponding core is above 4.0mm, the room temperature tensile streng...

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Problems solved by technology

[0003] Ring forgings produced by GH99 alloy require forging hardness HB(d) ≥ 3.51mm after solution treatment, and tensile strength requirements ≥ 930MPa. After conventional heat treatment, forging surface hardness HB(d) 3.51mm ~ 3.9mm often occurs, The hardness of the corresponding core is above 4.0mm, the tensile strength of the forging at room temperature is unqualified, and the surface hardness of the forging is uneven, and the hardness HB(d) of the same forging is between 3.51 and 4.3, which affects the production progress and delivery

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