Ni-Based Welding Wire Composition for Crack-Free High-Speed Joining
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Solution Overview
Problem
High-speed welding of Ni-based heat resistant alloy parts often results in weld metal cracking due to misrun of molten metal, inhibiting efficient production and repair of gas turbine components.
Innovation Solution
A welding wire with a specific composition (Cr: 14.0 to 21.5%, Co: 6.5 to 14.5%, Mo: 6.5 to 10.0%, W: 1.5 to 3.5%, Al: 1.2 to 2.4%, Ti: 1.1 to 2.1%, and controlled S and P impurities) and texture, featuring uniformly dispersed M6C and MC carbides in a γ phase matrix, is used to prevent weld metal cracking and enhance high-temperature tensile strength and ductility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If welding output power is increased to enhance welding speed, then productivity is improved, but weld metal cracking occurs due to misrun of molten metal
Solution Approach 1:
The invention changes the chemical composition parameters of the welding wire by precisely controlling the content ranges of Cr (18-22%), Co (10% or less), Al (0.2-0.7%), Ta/Mo/W (15-28%), C (0.09% or less), Zr (0.06% or less), and B (0.015% or less). This compositional parameter optimization modifies the molten metal's fluidity and solidification characteristics, preventing misrun and cracking while enabling high-speed welding without sacrificing reliability
Solution Approach 2:
The welding wire employs a composite alloy system combining multiple elements (Cr, Co, Al, Ta/Mo/W, C, Zr, B) in specific proportions to create a complex Ni-based heat-resistant alloy. This composite material design achieves synergistic effects where each element contributes specific properties: Cr for oxidation resistance, Al for strengthening, Ta/Mo/W for high-temperature strength, and B for grain boundary strengthening, collectively preventing weld metal cracking during high-speed welding
Data Source
AI summary
A wire for welding Ni-based heat resistant alloy, comprising: a composition containing, in mass %, Cr: 14.0 to 21.5%, Co: 6.5 to 14.5%, Mo: 6.5 to 10.0%, W: 1.5 to 3.5%, Al:l.2 to 2.4%, Ti:1.1 to 2.1%; Fe: 7.0% or less, B: 0.0001 to 0.020%, C: 0.03 to 0.15%, and a balance of Ni and unavoidable impurities, wherein a content of S and P contained in the unavoidable impurities is controlled to be, in mass%, S: 0.004% or less, and P: 0.010% or less, wherein the wire has a texture in which M6C type carbide and MC type carbide are uniformly dispersed in the matrix.