Submerged Arc Welding Wire Composition for Low-Temperature Toughness
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Solution Overview
Problem
The high cost of Ni-based solid wires for submerged arc welding, which are essential for achieving low-temperature toughness in weld metals, necessitates the development of an inexpensive alternative that maintains excellent low-temperature toughness without compromising mechanical properties.
Innovation Solution
A solid wire composition with a reduced Ni content and increased Mn content, along with other elements like Cr and B, is formulated to achieve a weld metal with excellent low-temperature toughness, where the total (Mn+Ni) content is 5.0% or more, and the fraction of fcc determined by magnetic induction is 70% or more, ensuring austenite single-phase formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Ni content is increased to 70% to secure low-temperature toughness of weld metal, then low-temperature toughness is improved, but manufacturing cost increases significantly
Solution Approach 1:
The patent changes the chemical composition parameters by reducing Ni content from 70% to 1.0-30.0% and increasing Mn content to 4.1-30.0%, while controlling the total (Mn+Ni) to 5.0% or more and (Mn+Ni+Cr) to 15.0% or more. This parameter optimization maintains austenite single-phase formation (fcc fraction ≥70%) and low-temperature toughness while significantly reducing manufacturing cost.
Solution Approach 2:
The patent replaces expensive Ni-based wire with a cheaper Mn-based wire composition. By using Mn as the primary austenite stabilizing element instead of Ni, the invention achieves the same low-temperature toughness performance at a fraction of the material cost, making the wire economically viable for widespread use.
2Ease of manufacture
If Mn content is increased to replace Ni to reduce cost, then manufacturing cost decreases, but toughness deteriorates and mechanical properties cannot be secured
Solution Approach 1:
The patent creates a composite chemical composition system combining Mn (4.1-30.0%), Ni (1.0-30.0%), and Cr (0-10.0%) with controlled totals of (Mn+Ni)≥5.0% and (Mn+Ni+Cr)≥15.0%. This composite approach leverages the synergistic effects of multiple elements: Mn provides cost reduction and austenite stabilization, Ni contributes to low-temperature toughness, and Cr enhances strength, achieving both cost efficiency and mechanical properties.
Solution Approach 2:
The patent optimizes multiple compositional parameters simultaneously: Mn content (4.1-30.0%), Ni content (1.0-30.0%), Cr content (0-10.0%), and their combined totals. By carefully balancing these parameters and controlling the fcc fraction to 70% or more, the invention achieves both cost reduction and maintained toughness, resolving the contradiction between using cheap Mn and preserving mechanical properties.
3Ease of manufacture
If only Mn is increased to reduce Ni content, then manufacturing cost decreases, but stacking fault energy decreases and toughness deteriorates
Solution Approach 1:
The patent controls the total (Mn+Ni) to 5.0% or more and (Mn+Ni+Cr) to 15.0% or more, preventing excessive Mn addition that would lower stacking fault energy. By maintaining these minimum totals and controlling the fcc fraction at 70% or more, the invention ensures adequate stacking fault energy is preserved while still achieving cost reduction through reduced Ni content.
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 proposed solid wire composition results in a weld metal with high strength and toughness, providing a cost-effective solution for submerged arc welding applications while maintaining excellent low-temperature properties.
Implementation Method 1
a fraction of fcc as determined by a magnetic induction method is 70% or more
Data Source
AI summary
A solid wire for submerged arc welding, in which a chemical component of the solid wire includes, by mass %, C: from 0% to 0.650%, Si: from 0.03% to 0.50%, Mn: from 4.1% to 30.0%, P: from 0% to 0.050%, S: from 0% to 0.050%, Cu: from 0% to 5.0%, Ni: from 1.0% to 30.0%, Cr: from 0% to 10.0%, Mo: from 0% to 10.0%, Nb: from 0% to 1.00%, V: from 0% to 1.00%, Co: from 0% to 1.00%, Pb: from 0% to 1.00%, Sn: from 0% to 1.00%, Al: from 0% to 0.10%, Ti: from 0% to 0.10%, B: from 0% to 0.1000%, N: from 0% to 0.5000%, O: from 0% to 0.0050%, and balance: Fe and impurities, (Mn+Ni) is 5.0% or more, (Mn+Ni+Cr) is 15.0% or more, and a fraction of fcc is 70% or more.