Cast Iron Cooking Surface Nitriding for Durable Oil Film Retention
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Solution Overview
Problem
Conventional cooking utensils face issues with surface durability, rust resistance, and manufacturing complexity, particularly in achieving a high-strength, scratch-resistant surface that maintains an oil film without requiring frequent seasoning or complex coating processes.
Innovation Solution
A method of manufacturing a cooking utensil using spheroidal graphite cast iron with a nitride layer formed on a mill scale surface, which is maintained without polishing, combining a diffusion hardening layer and a compound layer to enhance durability and rust resistance, while simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fluorine resin coating is applied to prevent burning, then burning prevention and ease of operation are improved, but oil wettability deteriorates and uniform oil spreading is hampered
Solution Approach 1:
The invention uses a composite surface structure consisting of a fluorine resin coating layer combined with a microporous layer underlying it. The fluorine resin provides non-stick properties and burning prevention, while the microporous layer beneath allows oil to penetrate and spread uniformly, resolving the contradiction between burning prevention and oil spreading uniformity.
2Strength
If surface nitriding is performed to provide scratch resistance and high strength, then surface durability is improved, but manufacturing complexity increases due to multiple layers and processes
Solution Approach 1:
The invention creates a composite surface structure with a nitride layer formed over a microporous layer. The nitride layer provides scratch resistance and high strength, while the microporous layer underneath maintains oil wettability. This composite approach achieves both durability and simplicity by combining functional layers rather than requiring multiple separate treatment processes.
Solution Approach 2:
The invention applies different properties to different depths of the surface: the outer nitride layer provides hardness and scratch resistance, while the underlying microporous layer provides oil wettability and retention. This local differentiation of material properties allows each layer to perform its specific function optimally.
3Shape
If the mill scale surface is polished to create a smooth surface, then surface finish is improved, but oil film retention deteriorates
Solution Approach 1:
The invention performs preliminary action by forming the microporous layer in the mill scale surface before applying the fluorine resin coating and nitride layer. This pre-formed microporous structure ensures oil film retention capability is established beforehand, while subsequent layers provide their respective functions without compromising the microporous structure.
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 results in a cooking utensil with improved durability, rust resistance, and ease of oil film formation, reducing the need for seasoning and simplifying the manufacturing procedure, while maintaining a high-strength, scratch-resistant surface.
Implementation Method 1
a nitride layer formed on a mill scale surface
Implementation Method 2
the oxidation coating formed on this surface provides a rust-resistant frying pan
Data Source
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AI summary
A method of manufacturing a cooking utensil includes: forming a cooking utensil made of a cast iron by casting; and forming a nitride layer by performing a nitriding on a cooking surface of the cooking utensil made of the cast iron.