Hot-dip Galvanized Steel Sheet Al-Mn Alloy Phase Adhesion
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Solution Overview
Problem
Hot-dip galvanized steel sheets experience low-temperature adhesion embrittlement and galling issues, which degrade product stability and productivity, particularly in cold climates, and existing solutions either compromise surface quality or increase operational complexity.
Innovation Solution
A hot-dip galvanized steel sheet with an Fe-Al based inhibition layer, a hot-dip galvanized layer, and a discontinuous Al-Mn based alloy phase, formed through controlled cooling and alloy composition, to randomly orient the zinc growth direction and enhance adhesion and hardness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the average grain size of the galvanized layer is increased to improve low-temperature adhesion, then low-temperature adhesion is improved, but image clarity and surface exterior are deteriorated
Solution Approach 1:
The patent applies local quality by creating an Al-Mn based alloy phase specifically at the interface between the inhibition layer and hot-dip galvanized layer, rather than uniformly treating the entire galvanized layer. This localized alloy phase formation (with 20-40% area ratio at the interface) improves low-temperature adhesion through enhanced interfacial bonding while preserving the surface quality of the outer galvanized layer, thus resolving the contradiction between adhesion improvement and surface exterior maintenance.
2Object-generated harmful factors
If liquid particles are sprayed on the plating layer to refine grains and improve galling properties, then galling properties improve, but operational complexity increases and surface defects may occur
Solution Approach 1:
The patent extracts the grain refinement function from the complex external liquid spraying facility and integrates it into the galvanizing process itself by adding Mn element to the molten zinc bath. This allows in-situ formation of Al-Mn alloy phases that refine the grain structure during solidification, eliminating the need for separate liquid spraying equipment and operations, thus reducing facility complexity while achieving grain refinement and improved galling properties.
Solution Approach 2:
The patent introduces Mn as an intermediary element in the molten zinc bath that mediates the grain refinement process. The Mn forms Al-Mn alloy phases that act as nucleation sites for grain refinement during solidification, providing a simpler chemical-mediated approach compared to physical liquid particle spraying, thereby reducing operational complexity while achieving the desired grain structure and galling resistance.
3Manufacturing precision
If rapid cooling is applied to refine grains and beautify surface, then surface quality improves, but (0001) surface orientation increases causing low-temperature adhesion embrittlement
Solution Approach 1:
The patent changes the compositional parameter by adding Mn to the zinc bath, which alters the solidification behavior and phase formation. The Al-Mn alloy phase formation with controlled composition (20-40% area ratio at the interface) enables grain refinement and surface quality improvement without inducing excessive (0001) orientation, thus maintaining low-temperature adhesion properties while achieving beautified 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 solution improves low-temperature adhesion and workability by preventing embrittlement fractures and reducing galling, maintaining surface quality and productivity.
Implementation Method 1
an Al-Mn based alloy phase discontinuously formed between the inhibition layer and the hot-dip galvanized layer
Implementation Method 2
as a zinc growth direction (orientation) of a galvanized layer is irregularly arranged
Implementation Method 3
A hot-dip galvanized steel sheet is a product obtained by coating a steel sheet with metal zinc
Implementation Method 4
an inhibition layer including an Fe-Al based intermetallic alloy phase formed on a base steel sheet
Data Source
Figure 1
Figure 2~3
AI summary
A preferred aspect of the present invention provides a hot-dip galvanized steel sheet having excellent low-temperature adhesion and workability, and a manufacturing method therefor, the hot-dip galvanized steel sheet comprising: an inhibition layer formed on a base steel sheet and comprising an Fe-Al-based intermetallic alloy phase; a hot-dip galvanized layer formed on the inhibition layer; and an Al-Mn-based alloy phase discontinuously formed between the inhibition layer and the hot-dip galvanized layer.