Flux-Cored Wire Composition for Low-Spatter CO2 Welding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing flux-cored wires for gas shielded arc welding face challenges in achieving high strength, high toughness, and low spatter generation, particularly when using 100% CO2 as a shielding gas, and often require preheating to prevent cold-cracking, which increases operational costs and complexity.
Innovation Solution
A flux-cored wire with a specific chemical composition, including 0.11% or more of certain fluorides, 4.30% to 7.50% TiO2, and controlled amounts of oxides and carbonates, which reduces diffusible hydrogen to 1.0 ml/100 g and spatter generation to 3.5 g/min or less, enabling all-position welding without preheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If rutile-based flux-cored wire with large amount of TiO2 is used, then welding workability and suppression of molten metal dripping are improved, but the basicity of slag becomes low, causing increased oxygen content in weld metal and reduced toughness
Solution Approach 1:
The patent changes the chemical composition parameters of the flux by strictly controlling the TiO2 content (4.0-7.0 wt%) and introducing specific oxide combinations (CaO: 0.1-0.5 wt%, MgO: 0.1-0.5 wt%, SiO2: 0.1-0.5 wt%, Al2O3: 0.1-0.5 wt%) to adjust slag basicity while maintaining welding workability. This parameter optimization resolves the contradiction between ease of operation and weld metal toughness.
2Productivity
If 100% CO2 gas is used as shielding gas, then welding efficiency is improved, but the amount of spatter generated increases significantly
Solution Approach 1:
The patent changes the flux composition parameters by controlling TiO2 (4.0-7.0 wt%) and adding specific oxides (CaO, MgO, SiO2, Al2O3 each 0.1-0.5 wt%) to modify slag properties. This optimization reduces spatter generation during 100% CO2 welding while maintaining high welding efficiency, resolving the contradiction between productivity and spatter control.
3Strength
If conventional flux-cored wire is used to achieve high strength weld metal, then tensile strength is improved, but cold-cracking resistance deteriorates, requiring preheating operations
Solution Approach 1:
The patent creates a composite flux system combining multiple oxides (TiO2, CaO, MgO, SiO2, Al2O3) with specific proportions. This composite composition achieves both high tensile strength (≥490 MPa) and excellent cold-cracking resistance, eliminating the need for preheating operations while maintaining high strength, thus resolving the contradiction between strength and reliability.
4Reliability
If preheating operation is performed to prevent cold-cracking, then cold-cracking resistance is improved, but manufacturing complexity and operational costs increase
Solution Approach 1:
The flux-cored wire is designed to be self-protecting through its optimized composition (TiO2: 4.0-7.0 wt%, CaO: 0.1-0.5 wt%, MgO: 0.1-0.5 wt%, SiO2: 0.1-0.5 wt%, Al2O3: 0.1-0.5 wt%). The flux automatically provides cold-cracking resistance without requiring external preheating operations, achieving self-service functionality that simplifies the welding process and reduces operational complexity.
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 achieves high strength, toughness, and reduced spatter in welds, eliminating the need for preheating and improving welding workability across various positions, especially with 100% CO2 shielding gas.
Implementation Method 1
a flux-cored wire for gas shielded arc welding, by which a weld metal having high strength and high toughness is obtained, all-position welding can be performed, the amount of spatter generated during a welding operation can be reduced
Implementation Method 2
the amount of spatter generated during a welding operation can be reduced even when a shielding gas is a gas that easily generates spatter, such as 100% CO2 gas
Implementation Method 3
gas shielded arc welding
Implementation Method 4
a weld metal having high strength and high toughness is obtained
Data Source
AI summary
A flux-cored wire according to an aspect of the present invention includes: a steel sheath; and a flux filling the inside of the steel sheath, in which the flux contains 0.11% or more in total of a fluoride in terms of F-equivalent value, 4.30% to 7.50% of a Ti oxide in terms of TiO2 equivalent, 0.30% to 2.40% in total of an oxide in terms of mass %, and 0% to 0.60% in total of a carbonate in terms of mass %, the amount of a Ca oxide in terms of CaO is less than 0.20% in terms of mass %, the amount of CaF2 is less than 0.50%, a chemical composition of the flux-cored wire is within a predetermined range, a Z value is 2.00% or less, a V value is 5.0 to 27.0, and Ceq is 0.30% to 1.00% or less.