Integrated Turbine Disc Alloy Control for Mixed Crystal Prevention
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Solution Overview
Problem
Existing disc-shaft integrated turbine discs for aerospace engines suffer from mixed crystals, failing to meet high-temperature durability and low-cycle fatigue performance requirements due to wide composition ranges and unstable manufacturing processes.
Innovation Solution
A manufacturing method involving vacuum induction melting, vacuum arc remelting, and triple smelting is employed to control the precise composition and microstructure of a nickel-base superalloy, ensuring uniform fine grains and optimal distribution of carbides and γ' phases, with controlled contents of C, Cr, Co, Al, Ti, O, N, S, and P to enhance mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional smelting and forging processes are used for disc-shaft integrated turbine discs, then manufacturing complexity is reduced, but the resulting microstructure contains mixed crystals which deteriorate high-temperature durability and low-cycle fatigue performance
Solution Approach 1:
The smelting process is divided into three separate stages (vacuum induction melting, vacuum arc remelting, and electroslag remelting) rather than using a single conventional smelting process. This segmentation allows each stage to address specific microstructure control requirements, ultimately producing uniform fine grains without mixed crystals while improving high-temperature durability and low-cycle fatigue performance
Solution Approach 2:
The patent implements triple smelting with controlled cooling rates and temperature parameters at each stage. The vacuum induction melting uses specific temperature ranges, followed by vacuum arc remelting with controlled solidification, and electroslag remelting with regulated cooling. These parameter changes throughout the multi-stage process ensure uniform fine grain structure formation, eliminating mixed crystals and improving reliability
2Strength
If wide composition ranges are used in the alloy, then manufacturing flexibility is improved, but the microstructure becomes unstable with mixed crystals, deteriorating mechanical properties
Solution Approach 1:
The patent specifies precise local composition ranges for each alloying element (C: 0.03-0.08%, Cr: 18.0-22.0%, Co: 12.0-16.0%, Mo: 3.0-6.0%, Al: 1.0-2.0%, Ti: 2.0-4.0%, etc.) rather than using wide composition ranges. This local quality control at the compositional level ensures stable microstructure formation during triple smelting, producing uniform fine grains without mixed crystals while maintaining manufacturing flexibility
Solution Approach 2:
The patent uses triple smelting processes (vacuum induction melting, vacuum arc remelting, electroslag remelting) with controlled parameters to achieve homogeneous distribution of alloying elements throughout the ingot. This homogeneity in composition prevents segregation and mixed crystal formation, resulting in stable microstructure with uniform fine grains and improved mechanical properties
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method produces a turbine disc with uniform fine grains, improved mechanical properties, and enhanced durability and fatigue resistance, meeting aerospace engine requirements at high temperatures with consistent performance across different parts.
Implementation Method 1
vacuum induction melting (VIM) includes: S1.2.1: raw material loading: loading a carbon powder, a cobalt block, and a molybdenum strip into a vacuum induction furnace
Implementation Method 2
after furnace materials are completely melted, electromagnetically stirring a resulting alloy liquid
Implementation Method 3
vacuum arc remelting (VAR) includes: S1.4.1: arranging an electrode in a crystallizer, conducting a centering treatment, and completing electrode welding in a vacuum arc furnace
Data Source
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AI summary
The present disclosure discloses a disc-shaft integrated turbine disc, and a manufacturing method thereof, and belongs to the technical field of turbine discs. The present disclosure solves the problem that the existing disc-shaft integrated turbine discs have mixed crystals and thus are difficult to meet the comprehensive requirements of high-temperature durability and low-cycle fatigue (LCF) performance. The disc-shaft integrated turbine disc includes a disc portion (1) and a shaft portion (2) penetrating through the disc portion (1), where the disc portion (1) and the shaft portion (2) are integrally formed; and the disc-shaft integrated turbine disc includes the following components in mass percentages: C: 0.02% to 0.04%, Cr: 18.5% to 20.0%, Co: 13.0% to 14.0%, Mo: 4.0% to 4.90%, Al: 1.3% to 1.6%, Ti: 2.80% to 3.25%, Ti/Al: 2.25 to 2.38, (Al + Ti): 4.35% to 4.58%, O: less than or equal to 20 ppm, N: less than or equal to 20 ppm, S: less than or equal to 10 ppm, P: less than or equal to 80 ppm, and nickel: the balance. The disc-shaft integrated turbine disc of the present disclosure has excellent comprehensive properties.