Floating Seal Material Composition for Hardness and Seizure Resistance
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Solution Overview
Problem
Existing floating seal materials face issues with low moldability, seizure resistance, and hardness, particularly in high-load applications, due to the composition and production process of Ni hard cast iron, which leads to casting defects and low chemical stability.
Innovation Solution
A floating seal material composed of specific ranges of Fe, C, Si, Mn, Cr, and Mo, with controlled carbide formation and a phase-separated structure, produced through centrifugal casting, to enhance moldability and seizure resistance while maintaining high hardness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If Ni hard cast iron is used to achieve high hardness, then wear resistance is improved, but seizure resistance deteriorates due to low chemical stability and residual austenite
Solution Approach 1:
The patent changes the chemical composition parameters by replacing Ni with Mo and adjusting Cr content, controlling C in 2.3-3.8%, Si in 0.7-2.5%, Mn in 0.3-1.3%, Cr in 3-13%, and Mo in 1.8-15%. This parameter optimization eliminates residual austenite while maintaining high hardness (64-68 HRC) and improves seizure resistance through enhanced chemical stability.
Solution Approach 2:
The patent creates a composite microstructure consisting of martensite matrix with dispersed carbides (M3C, M7C3, M6C). This composite structure combines the high hardness of martensite with the wear resistance and seizure resistance provided by the carbide particles, achieving balanced performance across multiple properties.
2Reliability
If high-Cr cast iron is used to improve seizure resistance, then seizure resistance is enhanced, but moldability deteriorates due to intense oxide generation during atmospheric melting
Solution Approach 1:
The patent optimizes Cr content to 3-13% (avoiding excessive Cr that causes intense oxidation) and introduces Mo (1.8-15%) which provides seizure resistance without the same oxidation problems. The controlled composition reduces oxide inclusion formation during atmospheric melting, improving moldability while maintaining seizure resistance.
Solution Approach 2:
Molybdenum acts as an intermediary element that provides seizure resistance through carbide formation without the intense oxide generation associated with high Cr content. Mo serves as a mediator that achieves the desired reliability without compromising ease of manufacture.
3Strength
If Ni hard cast iron is used to achieve high hardness, then wear resistance is improved, but moldability deteriorates due to casting defects like oxide inclusion and pinhole generation
Solution Approach 1:
The patent controls the chemical composition within specific ranges (C: 2.3-3.8%, Si: 0.7-2.5%, Mn: 0.3-1.3%, Cr: 3-13%, Mo: 1.8-15%) to optimize both hardness and moldability. This balanced composition achieves high hardness (64-68 HRC) while minimizing oxide inclusion and pinhole formation during casting, thereby improving moldability.
Solution Approach 2:
The martensite-carbide composite structure provides high hardness through the martensite matrix while the controlled carbide distribution and reduced oxide content improve casting quality and moldability.
4Strength
If the material composition is optimized for high hardness, then wear resistance is improved, but seizure resistance deteriorates under high-load applications
Solution Approach 1:
The patent optimizes the chemical composition to eliminate residual austenite (which causes seizure under high load) while maintaining high hardness. The controlled C, Si, Mn, Cr, and Mo content ensures martensitic structure formation with enhanced chemical stability, preventing seizure even under high-load conditions.
Solution Approach 2:
The martensite-carbide composite structure provides both high hardness for wear resistance and improved chemical stability for seizure resistance under high load. The dispersed carbides strengthen the matrix and prevent plastic flow that leads to seizure.
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 material achieves excellent moldability and seizure resistance under high loads, with a hardness of at least 64 HRC, reducing casting defects and improving wear resistance.
Implementation Method 1
produced through centrifugal casting
Data Source
AI summary
Provided is a floating seal material containing at least Fe, C, Si, Mn, Cr, and Mo, in which the content of C is 2.3% by weight or more and 3.8% by weight or less, the content of Si is 0.7% by weight or more and 2.5% by weight or less, the content of Mn is 0.3% by weight or more and 1.3% by weight or less, the content of Cr is 3% by weight or more and 13% by weight or less, the content of Mo is 1.8% by weight or more and 15% by weight or less, and the remainder is made up of Fe and unavoidable impurities.