Die Repair-Welding Composition for Oxide-Resistant Wear Control
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Solution Overview
Problem
Existing repair-welding materials for dies, particularly those used in hot-stamping molding, suffer from rapid wear due to the formation of hard oxides or nitrides on the surface, which are exacerbated by high temperatures and friction with the material being molded, leading to significant scratch wear despite having high hardness.
Innovation Solution
A repair-welding material with a composition that limits the content of Si, Cr, Mo, N, and O to suppress the formation of hard oxides and nitrides, while maintaining a thermal conductivity of 30 W/(m·K) or more and a hardness of 45 HRC or more, thereby reducing the likelihood of surface oxidation and wear during high-temperature molding processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the hardness of the repair-welding material is increased to suppress wear, then wear resistance is improved, but scratch wear caused by oxides and nitrides on the surface increases
Solution Approach 1:
The invention changes the chemical composition parameters of the repair-welding material by strictly limiting the content of oxide-forming elements (Si≤0.10%, Cr≤0.10%, Mo≤0.10%) and nitrogen content (N≤0.010%). This parameter optimization prevents the formation of hard oxides and nitrides on the surface during welding and subsequent heating processes, thereby eliminating scratch wear while maintaining adequate hardness (45-60 HRC) for wear resistance.
Solution Approach 2:
The invention converts the harmful effect of high-temperature oxidation and nitration during welding into a beneficial outcome by pre-limiting the content of elements that form hard oxides and nitrides. By controlling the chemical composition before welding, the material resists forming harmful surface compounds even when exposed to high temperatures, thus transforming a potentially harmful process into one that produces a clean, wear-resistant surface.
2Strength
If alloying elements are added to increase hardness, then strength is improved, but thermal conductivity decreases
Solution Approach 1:
The invention optimizes the parameter balance by setting specific composition ranges: C (0.20-0.40%), Mn (1.00-2.00%), and controlled amounts of alloying elements (Si, Cr, Mo ≤0.10% each). This parameter combination achieves adequate hardness (45-60 HRC) while maintaining thermal conductivity of 30 W/(m·K) or more, resolving the trade-off between strength and thermal conductivity.
3Reliability
If the content of Si, Cr, and Mo is increased to improve hardness, then wear resistance is improved, but the formation of hard oxides and nitrides is promoted
Solution Approach 1:
The invention applies parameter optimization by inverting the conventional approach: instead of adding Si, Cr, and Mo to increase hardness, it strictly limits their content (each ≤0.10%). This parameter change prevents oxide and nitride formation during welding and heating, while hardness is maintained through optimized C (0.20-0.40%) and Mn (1.00-2.00%) content, along with V (0.10-0.50%) additions.
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 repair-welding material effectively suppresses scratch wear by preventing the formation of hard oxides and nitrides, ensuring a durable and wear-resistant surface even at lower hardness levels, while maintaining sufficient hardness and thermal conductivity for die functionality.
Implementation Method 1
maintaining a thermal conductivity of 30 W/(m·K) or more... suppressing the formation of hard oxides and nitrides... during high-temperature molding processes
Implementation Method 2
scratch wear by an oxide or nitride generated on the surface... suppression of wear is important... hardness of 45 HRC or more
Data Source
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AI summary
Provided is a repair-welding material for die having a composition containing, by mass%: 0.18%≤C≤0.35%, 0.01%≤Si≤0.20%, 1.30%≤Mn≤1.90%, 0.50%≤Cr≤1.50%, 1.50%≤Mo≤2.50%, 0.30%≤V≤1.00%, N≤0.020%, and 0≤0.0050%, with a balance being Fe and inevitable impurities.