Large-size high-niobium high-temperature 706 alloy ingot and smelting process thereof

Abstract

The invention discloses a large-size high-niobium high-temperature 706 alloy ingot and a smelting process thereof. The problems that the serious melting loss of Al and Ti elements is prone to occurring to an existing smelting process and metallurgical defects of black spots and white spots are prone to occurring to the prepared high-niobium high-temperature 706 alloy ingot are solved. The smeltingprocess comprises the steps that vacuum induction melting is carried out, a plurality of vacuum induction ingots with the same component are prepared, then electroslag electrodes with the same numberare prepared, (CaF2-CaO-Al2O3-TiO2) quaternary slag is used for exchanging electroslag remelting, then prepared electroslag ingots are used for preparing consumable electrodes, and then the consumable electrodes are used as initial raw materials to perform twice vacuum consumable remelting. By adopting the smelting process, the high-niobium high-temperature 706 alloy large-size ingot with the ingot weight of more than 15 tons and the diameter of more than 800mm can be prepared, the formation of the metallurgical defects of the black spots and the white spots is restrained to the utmost extent, and the melting loss rate of the Al and Ti elements is reduced.

Description

technical field [0001] The invention relates to the technical field of large-size high-niobium alloys, more specifically, it relates to a large-size high-niobium high-temperature 706 alloy ingot and its smelting process. Background technique [0002] 706 superalloy is a special alloy, which causes the distortion of the base metal lattice by adding elements (chromium, tungsten, molybdenum, etc.) that are different in size from the base metal atoms (such as nickel) in the raw material, and the energy can be reduced by adding Elements with stacking fault energy (such as cobalt) in the alloy matrix and elements (tungsten, molybdenum, etc.) that can slow down the diffusion rate of matrix elements are added to strengthen the matrix. After aging treatment, the steel ingot can precipitate the second phase (γ′, γ″, carbide, etc.) from the supersaturated solid solution to strengthen the alloy. The structure of the γ′ phase is the same as that of the matrix, both of which are face-cent...

AI Technical Summary

Problems solved by technology

However, the preparation of large-sized electroslag ingots by double-arm exchange electrode remelting method is easy to form a series of quality defects such as injection, flow steel, composition fluctuations and inclusions during the electrode exchange process, even after subsequent high-temperature diffusion annealing And electrode forging can not completely eliminate the above quality defects

In the subsequent vacuum consumable remelting process, when smelting to the electrode joint, the above-mentioned quality defects will cause fluctuations in the smelting parameters of the consumable remelting process, and the 706 alloy with a high degree of alloying has a great influence on the consumable remelting process parameters. Very sensitive, parameter fluctuations can easily produce smelting defects such as black spots and white spots, which will affect the metallurgical quality of consumable ingots