Low-Manganese Flux-Cored Welding Electrode for Tough Low-Fume Welds
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Solution Overview
Problem
Conventional gas-shielded flux cored welding electrodes with titanium dioxide based slag systems contain high manganese levels, exceeding emissions control regulations and impairing weld metal toughness and ductility when manganese content is reduced to meet environmental standards.
Innovation Solution
A gas-shielded flux cored welding electrode with a ferrous metal sheath and core composition of 0.25 to 1.50 manganese, 0.02 to 0.12 carbon, 0.003 to 0.02 boron, 0.2 to 1.5 silicon, and 0 to 0.3 molybdenum, along with titanium, magnesium, or aluminum, optimized to reduce manganese content while maintaining weld metal properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional gas-shielded flux cored electrodes include significant manganese levels, then weld metal toughness and tensile properties are improved, but emissions control regulations are violated
Solution Approach 1:
The patent applies parameter changes by reducing manganese content from conventional levels (typically 2.0-3.0%) to low levels (0.25-1.50%), and simultaneously adjusting other alloying element parameters (carbon: 0.02-0.12%, boron: 0.003-0.02%, silicon: 0.2-1.5%, molybdenum: 0-0.3%) to maintain weld metal mechanical properties while meeting emissions regulations
Solution Approach 2:
The patent uses composite materials by formulating a multi-element alloy system where low manganese is combined with optimized levels of carbon, boron, silicon, and molybdenum to create a composite alloy composition that achieves both low emissions and adequate mechanical properties
2Object-affected harmful factors
If manganese content is reduced to meet emissions regulations, then manganese emissions are decreased, but weld metal toughness and ductility deteriorate
Solution Approach 1:
The patent changes multiple parameters simultaneously: reduces manganese to 0.25-1.50%, optimizes carbon to 0.02-0.12%, boron to 0.003-0.02%, silicon to 0.2-1.5%, and molybdenum to 0-0.3%, creating a new parameter space where low emissions and adequate toughness coexist
Solution Approach 2:
The patent introduces boron and silicon as intermediary elements that can compensate for reduced manganese, providing alternative mechanisms for improving weld metal toughness and ductility through grain refinement and deoxidation effects
Data Source
AI summary
A gas-shielded flux cored welding electrode comprises a ferrous metal sheath and a core within the sheath enclosing core ingredients. The core ingredients and sheath together comprise, in weight percentages based on the total weight of the core ingredients and the sheath: 0.25 to 1.50 manganese; 0.02 to 0.12 carbon; 0.003 to 0.02 boron; 0.2 to 1.5 silicon; 0 to 0.3 molybdenum; at least one of titanium, magnesium, and aluminum, wherein the total content of titanium, magnesium, and aluminum is 0.2 to 2.5; 3 to 12 titanium dioxide; at least one arc stabilizer, where the total content of arc stabilizers is 0.05 to 1.0; no greater than 10 of additional flux system components; remainder iron and incidental impurities.