Colored Stainless Steel Plate Surface Control for Press Moldability
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Solution Overview
Problem
Cold-rolled stainless steel plates with high strength are poor in moldability, leading to increased machining cracks and galling, and existing countermeasures using chlorine-based or high-viscosity oils pose environmental concerns and increase costs.
Innovation Solution
A colored stainless steel plate with a color coating layer thickness of 0.05 μm to 1.0 μm and Vickers hardness of 250 to 550 is achieved through cold-rolling, enhancing press moldability and galling resistance without using chlorine-based oils, by forming a deformed band with fine unevenness on the surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If cold-rolling is performed to increase strength, then Vickers hardness increases, but press moldability deteriorates and galling increases
Solution Approach 1:
The invention changes the surface condition parameter by creating fine unevenness with specific Ra values (0.03μm to 3μm) through controlled cold-rolling. This surface parameter modification allows the material to maintain high strength while improving press moldability and reducing galling, as the fine unevenness affects the friction and contact characteristics during pressing operations.
2Reliability
If chlorine-based extreme-pressure agents are used to prevent galling, then galling resistance improves, but environmental harm increases
Solution Approach 1:
The invention converts the potentially harmful cold-rolling process into a beneficial treatment by controlling the surface unevenness to specific parameters. This transforms what could be a source of galling into a mechanism that reduces galling and improves moldability, eliminating the need for harmful chlorine-based extreme-pressure agents.
Solution Approach 2:
The cold-rolling process itself creates the protective surface condition (fine unevenness with specific Ra values) that provides galling resistance. The material's own processing history becomes the source of protection, eliminating the need for external chemical agents and enabling self-protection against galling.
3Reliability
If high-viscosity press forming oil is used to improve galling resistance, then galling resistance improves, but cost increases
Solution Approach 1:
The controlled surface unevenness created during cold-rolling provides inherent galling resistance through modified friction characteristics. This self-generated protection eliminates the need for expensive high-viscosity press forming oils, reducing manufacturing costs while maintaining reliability.
4Adaptability or versatility
If thin plate is used for miniaturization, then functionality improves, but rigidity decreases
Solution Approach 1:
The invention modifies the surface parameter (Ra value) to create fine unevenness that enhances the mechanical properties of thin plates. This surface parameter change improves rigidity and reduces galling in thin-walled molded articles, enabling miniaturization while maintaining structural integrity.
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 improves press moldability and galling resistance, reducing the risk of machining cracks and environmental impact while maintaining high strength, thus enhancing productivity and reducing costs.
Implementation Method 1
The oxide film (color coating layer) 102 functions as an optical interference film. The stainless steel (color stainless steel plate) 100 exhibits various colors. More specifically, incident light L0 to the stainless steel 100 is divided into reflected light L1 reflected on the surface of the oxide layer 102 and reflected light L2 reflected on the surface of the stainless base material 101. The reflected lights L1 and L2 of two types interfere with each other due to the characteristics of wave to enhance light of a color depending on the thickness of the oxide layer 102.
Implementation Method 2
a deformed band which is formed on a surface of the color coating layer by cold rolling
Data Source
AI summary
A color coating layer is formed on the surface of a stainless steel plate by a chemical coloring method or an electrolytic coloring method. Thereafter, a colored stainless steel plate having the color coating layer is cold-rolled, the thickness of the color coating layer is adjusted to between 0.05 μm and 1.0 μm, and an entire plate thickness is adjusted to 0.5 mm or less. By the cold rolling a Vickers hardness Hv is between 250 and 550 to form a deformed band. As surface roughness, an arithmetic average roughness Ra is adjusted to between 0.05 μm and 5.0 μm. In this manner, the strength and rigidity of a thin colored stainless steel plate can be secured, and a color stainless steel plate and a colored stainless steel coil which do not easily cause galling and are excellent in press moldability can be obtained.