Zn-Al-Mg Coated Checkered Steel Plate for Flatness and Coating Uniformity
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Solution Overview
Problem
Checkered steel sheets used outdoors require improved corrosion resistance and flatness due to deformation caused by temperature changes, especially when coated with Zn—Al—Mg alloy, which has lower viscosity, leading to variations in coating layer thickness and deteriorated formability.
Innovation Solution
A Zn—Al—Mg alloy coated checkered steel sheet with specific chemical composition and controlled layer thickness ratios, along with controlled heating and cooling rates to minimize deformation and uniform coating application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hot-dip coating is applied to improve corrosion resistance, then corrosion resistance is improved, but deformation occurs due to temperature change between convex and flat parts, deteriorating flatness
Solution Approach 1:
The patent applies controlled heating and cooling rates as process parameters to minimize thermal deformation. By optimizing the heating rate to 5-20°C/s and cooling rate to 5-20°C/s, the temperature difference between convex and flat parts is reduced, preventing excessive deformation while maintaining corrosion resistance through hot-dip coating
Solution Approach 2:
The patent performs preliminary heating and cooling treatments before the hot-dip coating process. This preliminary thermal treatment stabilizes the sheet by reducing temperature gradients between convex and flat parts, preventing deformation during the subsequent coating process
2Reliability
If Zn—Al—Mg alloy coating is applied, then corrosion resistance is improved, but coating layer thickness varies due to lower viscosity, deteriorating formability
Solution Approach 1:
The patent optimizes the heating rate (5-20°C/s) and cooling rate (5-20°C/s) to control the viscosity characteristics of the Zn-Al-Mg alloy coating during the coating process. This parameter control ensures uniform coating thickness despite the inherently lower viscosity of the alloy, maintaining both corrosion resistance and formability
3Ease of operation
If convex parts are formed for anti-slip properties, then anti-slip performance is improved, but local thickness difference causes deformation during coating, deteriorating flatness
Solution Approach 1:
The patent controls the heating rate (5-20°C/s) and cooling rate (5-20°C/s) to minimize thermal expansion and contraction differences between convex and flat parts. This parameter optimization maintains the anti-slip convex structure while preventing deformation that would compromise flatness during the coating process
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 provides enhanced flatness, corrosion resistance, and formability by ensuring uniform heating and cooling of convex and flat parts, reducing coating layer variations.
Implementation Method 1
a difference occurs in an expansion amount and a shrinkage amount due to a temperature change between the convex part and the flat part of the checkered steel sheet
Data Source
AI summary
Provided is a Zn—Al—Mg alloy coated checkered steel sheet having on the sheet surface thereof convex part and flat part, wherein: the coating layer has a predetermined chemical composition, and when observing a cross section of cutting edge orthogonal to a longitudinal direction of the convex part and taken along a sheet thickness direction at a central part in the longitudinal direction of the convex part, a layer thickness ratio of the coating layer of the flat part on left and right of the convex part (layer thickness of left coating layer/layer thickness of right coating layer) is from 0.2 to 5.0, and a convex height T−t, where T is a sheet thickness of the substrate checkered steel sheet at the convex part and t is a sheet thickness of the substrate checkered steel sheet at the flat part, and a gap height x between a stationary surface and a sheet surface of the coated checkered steel sheet opposite to the stationary surface in a case in which the coated checkered steel sheet is placed in a stationary position satisfy the following Formulas 1 and 2 below.x/(T−t)≤1.5 Formula 1:0.5<T−t≤t Formula 2: