Hot-Stamped Steel Body With Zinc-Retaining Plated Coating
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Solution Overview
Problem
Existing hot stamping processes result in the evaporation of zinc from the metal coating, leading to deteriorated sacrificial corrosion resistance and red rust resistance in the hot stamped product.
Innovation Solution
A plated steel sheet with a specific element composition in the plated layer, subjected to steam oxidation during forming, forms an alloy layer that suppresses zinc evaporation and enhances corrosion resistance and coating adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a steel sheet with a metal coating containing zinc is heated for hot stamping, then the steel material can be accurately formed into a complicated shape with sufficient strength, but zinc is evaporated from the coating leading to deteriorated corrosion resistance and coating adhesion
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the metal coating. Specifically, it controls the zinc content within 2.0-24.0 wt%, silicon content within 7.1-12.0 wt%, and magnesium content within 1.1-8.0 wt%, while maintaining an Al/Zn ratio of more than 2.9. These parameter optimizations prevent zinc evaporation during hot stamping while preserving the required strength and improving corrosion resistance and coating adhesion.
2Productivity
If zinc is evaporated from the metal coating during heating, then the hot stamping process can be completed, but sacrificial corrosion resistance performance and red rust resistance are deteriorated
Solution Approach 1:
The patent employs composite materials by creating a multi-element metal coating system comprising zinc, silicon, magnesium, and aluminum. This composite coating structure, with specific compositional ratios, prevents zinc evaporation during hot stamping while enhancing both sacrificial corrosion resistance and red rust resistance, thus maintaining reliability throughout the manufacturing process.
3Reliability
If the metal coating composition is optimized to prevent zinc evaporation, then corrosion resistance and coating adhesion are improved, but the formability and strength of the steel material may be affected
Solution Approach 1:
The patent applies local quality by differentiating the functional requirements of different components: the metal coating (with optimized Zn-Si-Mg-Al composition) provides corrosion resistance and coating adhesion, while the underlying steel sheet maintains its formability and strength properties. This localized optimization of material properties in different layers resolves the contradiction between coating performance and base material performance.
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 effectively prevents zinc evaporation during hot stamping, resulting in improved corrosion resistance and coating adhesion of the hot stamped body.
Implementation Method 1
the surface of the plated layer was subjected to steam oxidation at the time of forming the plated layer
Implementation Method 2
Zn contained in a metal coating (plated layer) of the steel sheet is evaporated
Implementation Method 3
the base metal of the steel sheet reacts with the constituent elements of the plated layer to form an alloy layer
Implementation Method 4
quenching is performed simultaneously with forming by a press die
Implementation Method 5
obtain a part having steel made of martensite
Data Source
AI summary
A hot stamped body, including: a steel material; and a plated layer, wherein a chemical composition of the plated layer contains, in mass%, 0 to 70% of Al, 10 to 60% of Fe, 0 to 20% of Si, and a C-group element being any one kind or two kinds of Li and Y, with a content of 0.00001 to 0.3% in total, and optionally further contains any one kind or two or more kinds of Sb, Pb, B, Cu, Ti, Cr, Nb, Ni, Mn, Mo, Ag, Co, Sn, and Bi, and a remainder being of Zn and an impurity, wherein the plated layer contains an η-Zn phase or a Zn-containing phase is used.