Flux Cored Wire Composition for High-Strength Steel Welding
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Solution Overview
Problem
Current gas shielded arc welding technologies for high-strength steels with proof stresses of 690MPa or more face challenges in achieving efficient all-position welding with excellent cracking resistance, as existing flux cored wires often result in low welding efficiency and poor impact toughness due to high hydrogen content and slag component limitations.
Innovation Solution
A seamless flux cored wire composition with specific mass percentages of elements like C, Si, Mn, Ni, B, Cr, Al, TiO2, SiO2, ZrO2, and Al2O3, along with controlled hydrogen levels, optimized to enhance strength, toughness, and cracking resistance, allowing for high-efficiency all-position welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gas shielded arc welding using flux cored wire is adopted for high-strength steel, then welding efficiency is improved, but cracking resistance deteriorates due to high hydrogen content
Solution Approach 1:
The patent applies parameter changes by strictly controlling the chemical composition parameters of the flux cored wire, including limiting C content to 0.03-0.10%, Si to 0.25-0.70%, Mn to 1.00-3.00%, and particularly controlling total hydrogen content to 15ppm or less. This compositional parameter optimization resolves the contradiction by enabling high welding efficiency while maintaining excellent cracking resistance through reduced hydrogen content.
Solution Approach 2:
The patent employs composite material principles by creating a multi-component flux cored wire system with specific combinations of alloying elements (C, Si, Mn, Ni, B, Cr, Al) and oxide components (TiO2, SiO2, ZrO2, Al2O3). This composite formulation achieves both high welding efficiency and superior cracking resistance by synergistically combining elements that control hydrogen content, improve mechanical properties, and enhance weld metal quality.
2Adaptability or versatility
If flux cored wire with slag components is used, then all-position welding is enabled, but impact toughness deteriorates compared to other welding processes
Solution Approach 1:
The patent applies parameter changes by optimizing the oxide content parameters in the flux composition, specifically controlling TiO2 at 2.5-7.5%, SiO2 at 0.10-0.50%, ZrO2 at 0.20-0.90%, and Al2O3 at 0.10-0.40%. These parameter optimizations enable all-position welding through appropriate slag characteristics while simultaneously improving impact toughness by controlling slag inclusion formation and weld metal microstructure.
Solution Approach 2:
The patent applies local quality principles by creating distinct functional zones within the flux cored wire structure, with specific alloying elements and oxide components localized to perform different functions. The flux composition is designed with localized regions containing deoxidizers, slag formers, and hydrogen getters that work synergistically to provide both all-position welding capability and high impact toughness in the weld metal.
3Productivity
If high welding current is used for flux cored wire welding, then deposition efficiency is improved, but molten metal sagging occurs in positional welding
Solution Approach 1:
The patent applies parameter changes by optimizing the flux composition parameters to achieve appropriate slag viscosity and solidification characteristics. The controlled content of TiO2 (2.5-7.5%), SiO2 (0.10-0.50%), and other oxides ensures that the slag maintains proper viscosity at welding temperatures to support molten metal, while solidifying at appropriate rates to prevent sagging. This enables high welding current usage with good positional welding performance.
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 solution enables high-efficiency all-position welding with excellent cracking resistance and low-temperature toughness, improving weld metal quality and reducing hydrogen-induced cold cracking sensitivity.
Implementation Method 1
gas shielded arc welding of high-strength steel
Implementation Method 2
molten metal
Implementation Method 3
a slag component having a high melting point added in the cored wire solidifies upon welding in advance of a weld metal to thereby hold the weld metal
Implementation Method 4
an amount of diffusible hydrogen such as resulting from moisture contained in a flux material and resulting from moisture absorption during storage of the flux cored wire
Data Source
AI summary
The present invention provides a flux cored wire for gas shielded arc welding of high-strength steel having proof stress of 690MPa or more, which is capable of all-position welding with a higher efficiency and exhibits an excellent cracking resistance. The flux cored wire comprising a steel sheath, and a flux filled therein, wherein the flux cored wire comprises, by mass% with respect to the total mass of the flux cored wire: C: 0.03 to 0.10%, Si: 0.25 to 0.7%, Mn: 1.0 to 3.0%, Ni: 1.0 to 3.5%, B: 0.001 to 0.015%, Cr: limited to 0.05% or less, and Al: limited to 0.05% or less, and in the flux, TiO2: 2.5 to 7.5%, SiO2: 0.1 to 0.5%, ZrO2: 0.2 to 0.9%, and Al2O3: 0.1 to 0.4%; and the remainder comprising: Fe, arc stabilizer, and unavoidable impurities; and wherein the total mount of hydrogen in the flux cored wire is in 15ppm or less.