Ferritic Stainless Steel Welding Wire Composition for Heat and Oxidation
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Solution Overview
Problem
Ferrite-based stainless steel welding wires face a challenge in balancing high-temperature strength and oxidation resistance due to the addition of elements like Nb, Mo, W, and Ti, which can deteriorate weldability and oxidation resistance.
Innovation Solution
A ferrite-based stainless steel welding wire with specific composition limits and additive balances, defined by formulas (1), (2), and (3), ensuring high-temperature strength and oxidation resistance, including elements like Nb, Mo, W, Si, Ti, and Al, while maintaining weldability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If Nb, Mo, W, and Ti are added to improve high-temperature strength, then high-temperature strength is improved, but oxidation resistance deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the composition ratios of Nb, Mo, W, and Ti within specific ranges defined by formulas (1), (2), and (3). Formula (1) ensures sufficient high-temperature strength through minimum combined content, while formulas (2) and (3) limit individual and total amounts to prevent oxidation resistance deterioration. This quantitative parameter optimization resolves the contradiction between strength improvement and oxidation resistance maintenance.
2Strength
If Ti is added to prevent Nb carbonitride formation, then high-temperature strength is maintained, but weldability deteriorates
Solution Approach 1:
The patent resolves this contradiction through parameter changes by strictly limiting Ti content to 0.001% to 0.150% and establishing formula (3) where [Ti]+[Al]≤0.15. This quantitative control prevents excessive Ti addition that would cause weldability deterioration while maintaining sufficient Ti to prevent Nb carbonitride formation and preserve high-temperature strength.
3Strength
If Mo and W are added to improve high-temperature strength, then high-temperature strength is improved, but oxidation resistance deteriorates
Solution Approach 1:
The patent applies parameter changes by defining formula (2) where [Mo]+[W]≤3.6 and setting specific content ranges for Mo (0.01% to 3.60%) and W (0.01% to 3.60%). This quantitative control ensures sufficient Mo and W content to achieve desired high-temperature strength while preventing excessive addition that would deteriorate oxidation resistance.
Data Source
AI summary
Provided is a ferrite-based stainless steel welding wire that has excellent oxidation resistance properties and high temperature strength. This ferrite-based stainless steel welding wire has a composition containing, in mass %, 0.001-0.050% of C, 0.01-2.00% of Si, 0.01-1.50% of Mn, 0.030% or less of P, 0.010% or less of S, 16.0-25.0% of Cr, 0.001-0.150% of Ti, 0.020% or less of O, and 0.05% or less of N, further containing at least one selected from 0.01-1.80% of Nb, 0.01-3.60% of Mo, and 0.01-3.60% of W, and satisfying formulae (1), (2), and (3), with a balance being Fe and unavoidable impurities. Formula (1): [Nb]+[Mo]+[W]+0.25[Si]≥2.2, formula (2): [Mo]+[W]≤3.6, formula (3): [Ti]+[Al]≤0.15, where [ ] in the formulae represents the content in mass % of the element indicated in [ ].