Layer Sintered Valve Seat Ring Creep Resistance
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Solution Overview
Problem
Layer-sintered valve seat rings experience significant relaxation when used in cast iron alloy cylinder heads, leading to a loss of press fit and potential engine failure due to the lower creep resistance of the cheaper support material compared to the function material.
Innovation Solution
A layer-sintered valve seat ring design incorporating a support material with specific compositions (C, Cr, Mo, W, V, Cu, Fe, and optional Mn, Si, Ni, Co, Ca, P, and S) that reduces relaxation, combined with a method involving uniaxial pressing, sintering under controlled atmospheres, and heat-treating to enhance mechanical properties, allowing for a stable press fit with cast iron alloy cylinder heads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a cheaper support material with lower creep resistance is used in layer-sintered valve seat rings, then material costs are reduced, but relaxation and loss of press fit occur during operation
Solution Approach 1:
The patent applies parameter changes by precisely controlling the chemical composition of the support material (specific ranges of C, Cr, Mo, W, V, Cu, Fe, Mn, and Si) to achieve optimal creep resistance. This allows the use of a cost-effective support material while maintaining sufficient high-temperature stability to prevent relaxation and press fit loss during engine operation.
2Quantity of substance
If a layer-sintered valve seat ring with support material and function material is used, then material costs are lowered, but relaxation occurs in cast iron alloy cylinder heads
Solution Approach 1:
The patent controls chemical composition parameters of the support material to achieve dimensional stability. The specific alloying elements and their ranges are designed to minimize thermal creep and plastic deformation, ensuring the valve seat ring maintains its outer diameter and press fit in cast iron cylinder heads during high-temperature operation.
Solution Approach 2:
The patent uses a composite structure with function material and support material in specific layers. The support material is engineered with specific composition to provide dimensional stability, while the function material provides tribological performance. This composite approach allows cost reduction through the support material while maintaining overall stability through the function material and optimized interface.
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 solution effectively prevents loosening or detachment of the valve seat ring during operation, maintaining a stable press fit and reducing the risk of engine failure by enhancing the support material's creep resistance and mechanical stability.
Implementation Method 1
a method involving uniaxial pressing, sintering under controlled atmospheres, and heat-treating
Implementation Method 2
a method involving uniaxial pressing, sintering under controlled atmospheres, and heat-treating to enhance mechanical properties
Data Source
AI summary
A layer-sintered valve seat ring is disclosed. The layer-sintered valve seat ring includes at least two materials including a function material for a tribological contact with an opposite runner and a support material for the function material. The support material includes: C: 0.5 to 1.8% by weight; Cr: 3 to 16% by weight; Mo: 1 to 5% by weight; W: 0.5 to 5.5% by weight; V: 0.4 to 4.0% by weight; Cu: 12 to 25% by weight; Fe: 41.3 to 82.6% by weight; Mn: up to 0.6% by weight; Si: up to 1.8% by weight; and a remainder of production-related contamination in the form of at least one of Ni, Co, Ca, P, and S that are present in contents of <0.3% by weight each.