Smelting process of high-niobium high-temperature alloy large-size ingot and high-niobium high-temperature alloy large-size ingot

Abstract

The invention discloses a smelting process of a high-niobium high-temperature alloy large-size ingot and the high-niobium high-temperature alloy large-size ingot. The problems that metallurgical defects of black spots and white spots are formed by anabatic segregation due to expansion of diameter or weight of the high-niobium high-temperature alloy large-size ingot, steel ingots are exploded due to large heat stress and the weight of the steel ingots cannot be increased due to the tonnage restriction of vacuum induction melting equipment are solved. The smelting process comprises the steps that 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 number are prepared, exchanging electroslag remelting is carried out, then prepared electroslag ingots are used for preparing consumable electrodes, and then the consumable electrodes are used as initial raw materials to perform multiple 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, the element segregation degree is reduced, and the steelingots are effectively prevented from being exploded.

Description

technical field [0001] The present invention relates to the technical field of high-niobium superalloy large-size ingot casting, more specifically, it relates to a high-niobium superalloy large-size ingot smelting process and the high-niobium superalloy large-size ingot produced by the smelting process . Background technique [0002] With the improvement of thermal efficiency and power of industrial gas turbines, the turbine disc material of advanced heavy-duty gas turbines above 200MW is gradually upgraded from alloy steel to superalloy. Compared with alloy steel, the yield strength of high-temperature alloys at 500°C is increased by more than 40%, and the durability strength at 550°C for 100,000h is increased by more than 300%, which can significantly improve the high-temperature strength and long-term durability of heavy-duty gas turbine wheels, which is conducive to simplifying the structure Designed to improve reliability and thermal efficiency of gas turbines. [000...

AI Technical Summary

Problems solved by technology

[0007] In view of the deficiencies in the prior art, the first object of the present invention is to provide a smelting process for large-size ingots of high-niobium superalloys, which can effectively solve the problems caused by the expansion of the diameter or weight of large-size ingots of high-niobium superalloys. Segregation intensifies to form metallurgical defects of black spots and white spots, steel ingots burst due to high thermal stress, and the weight of steel ingots cannot be increased due to the tonnage limit of the electrode arm of the electroslag remelting equipment, so that the ingot weight of more than 15 tons can be realized 1. The preparation of large-size high-niobium superalloy ingots with a diameter of more than 800mm can suppress the formation of black spots and white spot metallurgical defects to the greatest extent, reduce the degree of element segregation, and effectively prevent steel ingots from bursting