Method for controlling grain size of high-temperature alloy forge piece through heat treatment

Abstract

The invention discloses a method for controlling the grain size of a high-temperature alloy forge piece through heat treatment, which comprises the following steps of 1) carrying out two stages of sub-temperature homogenizing annealing and slow cooling, heating a forge piece to 600 DEG C, and keeping the temperature for 2 hours; raising the temperature to 1000 DEG C within 5 hours, and keeping thetemperature for 2 hours; raising the temperature to 1155 +/-5 DEG C within 2 hours, and keeping the temperature for 24 hours; raising the temperature to 1200 +/-10 DEG C within 1 hour, and keeping the temperature for 96 hours; cooling the high-temperature alloy forge piece along with a furnace; 2) carrying out the solid solution and grading failure treatment after forging, heating to 600 DEG C, and keeping the temperature for 1 hour; raising the temperature to 970 +/-8 DEG C within 0.5 hour, and keeping the temperature for 1.5 hours; air cooling; heating to 600 DEG C, and keeping the temperature for 1 hour; raising the temperature to 720 +/-5 DEG C within 0.5 hour, and keeping the temperature for 8 hours; cooling to 620 +/-5 DEG C within 2 hours, and keeping the temperature for 8 hours; air cooling. By adopting the two stages of long-time sub-temperature homogenizing annealing treatment, the brittle laves phases and delta phases in the steel ingot are eliminated, and the formation ofa low-melting-point eutectic phase is avoided; a trace delta phase is separated out during the solid solution treatment process, and the high-temperature lasting notch sensitivity is eliminated; and by carrying out the aging treatment twice, the gamma ''-phase and gamma '-phase particles are dispersed and separated out.

Description

technical field [0001] The invention relates to the field of forging and heat treatment, in particular to a method for controlling the grain size of a superalloy forging through heat treatment. Background technique [0002] The mechanical properties at high temperature cannot be the same as the mechanical properties at room temperature. On the basis of the mechanical properties at room temperature, they are also related to temperature and time. Therefore, the mechanical properties at high temperature are the comprehensive factors of the relationship between temperature, time, stress and strain. When the temperature rises, the grain and grain boundary strength will decrease, but due to the irregular arrangement of atoms on the grain boundary, diffusion is easy to proceed through the grain boundary, so the grain boundary strength decreases rapidly. The temperature at which the grains and grain boundaries are equal in strength is called the isointense temperature. When the temp...

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Problems solved by technology

[0004] The temperature range of superalloy forging is narrow (1 / 3~1 / 2 of that of carbon steel), and superalloy forgings are prone to serious problems such as overheating, overburning, local coarse grains, and uneven deformation during hot forming, which ultimately affect Its service performance and life

Simply relying on experience, it is difficult to realize the comprehensive control of fine grain and microstructure homogenization of large-scale superalloy forgings

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