Fused Tuckstone Skin Microstructure for Thermal Stress Resistance
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Solution Overview
Problem
Glass furnace tuckstones face challenges in resisting thermal stresses, cracking, and corrosion, leading to reduced service life and potential defects in glass products due to insufficient thermomechanical strength and resistance.
Innovation Solution
A fused tuckstone with a skin microstructure on specific surfaces, particularly the lower transition surface, and a curved junction surface between the superstructure and tank arms, along with a constant thickness and minimal machining to retain the skin microstructure, enhances thermomechanical strength and corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional fused refractory products are used for tuckstones, then the furnace can operate at high temperatures, but the tuckstones are insufficiently resistant to thermal stresses and cracking
Solution Approach 1:
The patent applies local quality by creating a skin microstructure specifically on the lower transition surface of the tuckstone, which is the area subjected to highest thermal stress. This localized microstructural modification (higher crystal density in the skin layer) provides enhanced resistance to cracking at the critical stress point without requiring the entire tuckstone to have uniform high-strength properties, thus resolving the contradiction between overall strength and localized crack resistance.
2Reliability
If the tuckstone is made with high zirconia content to improve corrosion resistance, then the service life increases, but the thermomechanical strength may be compromised
Solution Approach 1:
The patent resolves this contradiction by creating a differentiated microstructure where the skin layer has higher crystal density (improving strength) while the bulk material maintains the corrosive-resistant composition. The skin microstructure is formed on the surface exposed to thermal stress, while the interior retains the zirconia-rich composition for corrosion resistance, allowing both properties to coexist in their respective locations.
3Manufacturing precision
If the lower transition surface is heavily machined to ensure precise fit, then the assembly precision improves, but the skin microstructure is removed reducing corrosion resistance
Solution Approach 1:
The patent applies partial action by performing minimal machining only on the horizontal support surface to ensure precise fit with the metallic structure, while deliberately leaving the lower transition surface (the inclined surface) with its skin microstructure intact. This selective approach achieves sufficient assembly precision without removing the protective skin layer from the corrosion-prone inclined surface.
4Ease of manufacture
If the tuckstone design includes sharp corners and ridges for structural definition, then the manufacturing is easier, but the stress concentration increases leading to cracking
Solution Approach 1:
The patent applies curvature by specifying that the lower transition surface should have a radius of curvature of at least 5 mm, eliminating sharp corners and ridges. This rounded geometry distributes thermal stresses more evenly across the surface, preventing stress concentration that would lead to cracking, while still allowing for straightforward manufacturing of the curved surface.
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 skin microstructure significantly improves the tuckstone's thermomechanical strength and corrosion resistance, extending the service life of the furnace and preventing defects in glass products by maintaining structural integrity under varying temperatures and corrosive conditions.
Implementation Method 1
The tuckstone must tolerate high thermal stresses since the superstructure arm 30 is partially in an environment at temperatures close to ambient temperature, generally thanks to blown air cooling, while the tank arm 32, partially inside the furnace, is exposed to temperatures of around 1500° C.
Implementation Method 2
The tuckstone must also be resistant to corrosion from the aggressive vapors of the furnace and condensates.
Implementation Method 3
the upper transition surface, at the junction between the superstructure and tank arms, comprises a curved surface, i.e. not flat, with no ridges
Implementation Method 4
the tuckstone undergoes thermal cycles due to alternating operation of the burners and maintenance operations
Data Source
AI summary
Fused tuckstone defining lower and upper surfaces. The lower surface includes a support surface to rest on metallic structure of a glass furnace, a tank surface intended to face an upper edge of a tank of the furnace, and a lower transition surface connecting the support and tank surfaces. The upper surface includes a superstructure surface to receive a side wall of a superstructure of the furnace and an upper transition surface connecting the superstructure and lower surfaces. At least a part of the lower transition surface has a crystal density of more than four times the crystal density at a depth of 4 centimeters below the lower transition surface, a crystal density being evaluated by the number of crystals having a surface area of more than 12 μm2 per mm2 of surface after polishing, the crystal density at the depth being evaluated after cutting of the tuckstone.