Titanium-Clad Structural Steel Plate With Strong Splash-Zone Bonding
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Solution Overview
Problem
Existing methods for manufacturing clad steel plates do not adequately address the corrosion resistance, yield-to-tensile ratio, and low-temperature impact performance requirements necessary for structural steels used in sea wave splash zones, leading to premature corrosion and structural failure.
Innovation Solution
A 345-MPa-grade hot-rolled steel plate with a low-carbon microalloyed composition design, featuring a base layer with controlled chemical elements and a thin interface transition layer, combined with industrial pure titanium as the corrosion-resistant layer, achieved through specific heating, rolling, and cooling processes to ensure excellent bonding and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If titanium is used as the corrosion-resistant layer, then corrosion resistance is improved, but the formation of brittle TiC compounds at the interface reduces interfacial bonding strength
Solution Approach 1:
A nickel-based alloy isolation layer is introduced between the titanium corrosion-resistant layer and the carbon steel base layer. This intermediary layer prevents direct contact between titanium and carbon, blocking the formation of brittle TiC compounds at the interface. The nickel-based alloy serves as a mediator that maintains both the corrosion resistance of titanium and the bonding strength of the interface.
Solution Approach 2:
The carbon element is extracted or removed from the interface region by using the nickel-based alloy isolation layer as a barrier. This prevents carbon from diffusing into the titanium layer and forming harmful TiC compounds, thereby maintaining interfacial bonding strength while preserving titanium's corrosion resistance.
2Strength
If tensile strength is increased, then structural strength is improved, but the yield-to-tensile ratio increases making it difficult to achieve low yield-to-tensile ratio
Solution Approach 1:
The chemical composition parameters of the base layer are precisely controlled and optimized. By adjusting the contents of alloying elements such as Mn, Si, and microalloying elements like Ti and Nb within specific ranges, the steel achieves both high tensile strength and appropriate yield-to-tensile ratio. This parameter optimization allows the material to meet both strength requirements and deformation characteristics needed for seismic resistance.
Solution Approach 2:
The steel plate employs a composite structure consisting of a carbon steel base layer and a titanium corrosion-resistant layer, with a nickel-based alloy isolation layer at the interface. This composite material design allows the base layer to provide high tensile strength while the controlled composition ensures appropriate yield-to-tensile ratio, achieving both goals simultaneously through material composition design.
3Strength
If microalloying elements are added to increase strength, then tensile strength is improved, but excessive addition leads to coarse precipitates reducing low-temperature impact toughness
Solution Approach 1:
The content of microalloying elements (Ti: 0.008-0.018%, Nb: 0.02-0.065%) is precisely controlled within narrow ranges. This parameter optimization ensures sufficient precipitation strengthening for high tensile strength while preventing excessive precipitate formation that would harm low-temperature impact toughness. The balanced composition achieves both strength and toughness requirements.
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 steel plate exhibits corrosion resistance of ≤ 0.006 mm/year, yield strength of ≥ 350 MPa, tensile strength of ≥ 490 MPa, yield-to-tensile ratio of 0.71-0.80, and impact energy of ≥ 190 J at -40°C, meeting the requirements for structural safety in wave splash zones with high economic efficiency.
Implementation Method 1
heating the clad slab to 900-1000°C to form an interface transition layer between the base layer and the corrosion-resistant layer
Implementation Method 2
rolling the clad slab with a reduction rate per pass of 5-20%, a cumulative reduction rate of ≥70% and a finishing rolling temperature of 750-850°C to achieve full bonding between the base layer and the clad layer
Implementation Method 3
applying water cooling at a cooling rate of 5-20°C/s and a final cooling temperature of 300-650°C
Implementation Method 4
Titanium exhibits high chemical activity and readily reacts with oxygen in the air to form oxides. The oxides on the titanium metal surface are dense, stable, and possesses a strong 'self-healing' ability.
Data Source
Figure 1~3
Figure 4~5
AI summary
The present disclosure provides a hot-rolled steel plate for construction structures, comprising a base layer, a corrosion-resistant layer, and an interface transition layer located between the base layer and the corrosion-resistant layer. The hot-rolled steel plate of the present disclosure has a yield strength of ≥ 350 MPa, a tensile strength of ≥ 490 MPa, a yield-to-tensile ratio of 0.71-0.80, an impact energy at -40°C of ≥ 190 J, a sea wave splash corrosion resistance rate of ≤0.006 mm/year, an interface transition layer thickness of ≤ 10 µm, and an interfacial shear strength of ≥ 252 MPa, and can be used to manufacture structural components suitable for see wave splash zone environments. The present disclosure also provides a manufacturing method for the hot-rolled steel plate.