Steel Joint Interface Carbon Gradient for Strength and Wear Resistance
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Solution Overview
Problem
Existing methods for joining steels do not efficiently enhance joint strength and wear resistance of the outer periphery of the joint.
Innovation Solution
A steel joined body with a joint interface having a carbon concentration of 0.20 mass % or more and 2.10 mass % or less, and a concentration gradient layer with decreasing carbon concentration from the joint interface, is manufactured by disposing a carbonaceous material on the joining surfaces, overlapping them, and heating to a maximum temperature of 1150° C. or higher and 1500° C. or lower.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If carbonaceous material is applied to joining surfaces and steels are heated and pressed in a reducing atmosphere, then the steels are joined together, but the joint strength between the steels is not efficiently enhanced
Solution Approach 1:
The patent changes the chemical composition parameters by controlling carbon concentration in the joint interface to be 0.20-2.10 mass% and creating a concentration gradient layer. This parameter optimization resolves the contradiction by achieving high joint strength through precise compositional control rather than relying solely on traditional hot pressing methods
Solution Approach 2:
The patent applies local quality by creating a concentration gradient layer where carbon concentration varies with distance from the joint interface. This localized compositional variation enhances joint strength at the interface while maintaining appropriate properties in the bulk material, efficiently resolving the strength enhancement issue
2Reliability
If traditional hot joining method is used, then steels can be joined, but wear resistance of the outer periphery of the joint is not enhanced
Solution Approach 1:
The patent changes the carbon concentration parameter to 0.20-2.10 mass% at the joint interface and maintains a concentration gradient, which simultaneously enhances both joint strength and wear resistance. This parameter optimization achieves improved reliability without requiring additional manufacturing steps
Solution Approach 2:
The concentration gradient layer creates local quality variation where the outer periphery of the joint has enhanced carbon content for improved wear resistance, while the interior maintains appropriate properties. This localized enhancement achieves the wear resistance goal without increasing overall process 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 method efficiently enhances the joint strength and wear resistance of the steel joined body, suppressing crystallization of hard and brittle solidification structures and enhancing the hardness of the joint interface.
Implementation Method 1
heating the steels having the joining surfaces overlapped at a maximum temperature of 1150° C. or higher and 1500° C. or lower, the carbonaceous material being disposed to generate a liquid phase on the joining surfaces at the maximum temperature
Implementation Method 2
the steel joined body including a concentration gradient layer having a carbon concentration decreasing with distance from the joint interface
Data Source
AI summary
A method for manufacturing a steel joined body having a plurality of steels joined together, the method comprising: disposing a carbonaceous material on at least one joining surface of steels to be joined together; overlapping joining surfaces of the steels to be joined together having the carbonaceous material interposed between the joining surfaces; and heating the steels having the joining surfaces overlapped at a maximum temperature of 1150° C. or higher and 1500° C. or lower, the carbonaceous material being disposed to generate a liquid phase on the joining surfaces at the maximum temperature, the carbon concentration in a joint interface after high frequency induction heating was adjusted to 0.20 mass % or higher and 2.10 mass % or lower by controlling a heating and holding time at the maximum temperature.