Stainless Steel Composite Plate With Low Yield Ratio for Weathering Bridges
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Solution Overview
Problem
Existing stainless steel composite plates for weathering steel bridges face challenges in achieving good atmospheric corrosion resistance without excessive alloy costs and maintaining high strength and toughness, while also requiring improved production processes to ensure a low yield ratio for stability.
Innovation Solution
A stainless steel composite plate with a base material and covering material composition optimized for atmospheric corrosion resistance, using austenitic stainless steel with ultra-low carbon and micro-titanium, and a specific chemical composition, combined with a multi-step production process including continuous casting, gas shielded welding, controlled rolling, and tempering heat treatment to achieve a low yield ratio and excellent metallurgical bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If alloying elements (Cr, Ni, Cu) are added to weathering bridge steel to improve atmospheric corrosion resistance, then corrosion resistance is improved, but alloy cost increases excessively
Solution Approach 1:
The patent optimizes the content ranges of alloying elements (Cr: 0.40-0.60%, Ni: 0.31-0.45%, Cu: 0.31-0.50%) to achieve the required atmospheric corrosion resistance index (I≥6.0) while minimizing alloy costs. This parameter optimization resolves the contradiction by finding the minimum effective dosage of expensive alloying elements.
Solution Approach 2:
The patent uses a composite structure with base material (weathering bridge steel) and covering material (austenitic stainless steel with ultra-low carbon and micro-titanium). The covering material provides enhanced corrosion resistance with controlled alloy content, while the base material provides structural support, collectively achieving cost-effective corrosion protection.
2Reliability
If alloying elements are added to weathering bridge steel to improve atmospheric corrosion resistance, then corrosion resistance is improved, but high-temperature deformation resistance and recrystallization temperature change greatly
Solution Approach 1:
The patent carefully controls the content ranges of alloying elements and introduces specific elements (Nb: 0.010-0.060%, V≥0.080%, Ti: 0.008-0.018%) that form fine precipitates to pin grain boundaries. This micro-alloying strategy maintains high-temperature deformation resistance while achieving the required atmospheric corrosion resistance.
Solution Approach 2:
The patent applies different material compositions to different layers: the base material contains controlled amounts of Cr, Ni, and Cu for corrosion resistance, while the covering material uses ultra-low carbon austenitic stainless steel with micro-titanium for enhanced corrosion resistance without compromising the base material's high-temperature properties.
3Productivity
If vacuum rolling composite method is used to produce stainless steel composite plate, then production efficiency is improved and environmental friendliness is enhanced, but the base material surface cannot form an effective rust layer with good atmospheric corrosion resistance
Solution Approach 1:
The patent uses vacuum rolling composite method to produce a composite plate with base material (weathering bridge steel) and covering material (austenitic stainless steel with ultra-low carbon and micro-titanium). The covering material provides the required atmospheric corrosion resistance index (I≥6.0) while the composite structure enables mass production with high efficiency and environmental friendliness.
Solution Approach 2:
The patent optimizes the chemical composition parameters of both base material and covering material to achieve the required atmospheric corrosion resistance index (I≥6.0) while maintaining compatibility with vacuum rolling composite process, thus resolving the contradiction between production efficiency and corrosion resistance.
4Reliability
If weathering bridge steel with high alloy content is used to ensure good atmospheric corrosion resistance, then corrosion resistance is improved, but yield ratio increases requiring further process development
Solution Approach 1:
The patent optimizes the chemical composition parameters of the base material (C: 0.04-0.09%, Si: 0.15-0.40%, Mn: 1.20-1.50%, etc.) to achieve the required atmospheric corrosion resistance index (I≥6.0) while controlling the yield ratio to be ≤0.83 through micro-alloying with Nb, V, and Ti that form fine precipitates for grain boundary strengthening without excessive alloy content.
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 results in a composite plate with enhanced atmospheric corrosion resistance, reduced yield ratio, and improved metallurgical bonding, ensuring high shear strength and intergranular corrosion resistance, suitable for railway weathering steel bridges with no intergranular corrosion and no cracking upon 180° bending.
Implementation Method 1
austenitic stainless steel with ultra-low carbon design and micro-titanium... Ti is added and preferentially combined with C to solidify C, thereby reducing the precipitation of Cr23C6 during the rolling
Implementation Method 2
reducing the precipitation of Cr23C6 during the rolling
Implementation Method 3
gas shielded welding
Implementation Method 4
controlled rolling
Implementation Method 5
controlled rolling, and tempering heat treatment
Implementation Method 6
tempering heat treatment to achieve a low yield ratio and excellent metallurgical bonding
Implementation Method 7
tempering heat treatment
Implementation Method 8
vacuum pumping is performed between the covering material and the covering material, a vacuum degree is controlled to be below 50 Pa
Implementation Method 9
water blasting to obtain final products
Data Source
AI summary
Disclosed in the present disclosure is a stainless steel composite plate for a weathering steel bridge having a low yield ratio, comprising a base material and a covering material which satisfy that an atmospheric corrosion resistance index I is greater than or equal to 6.0, the total thickness being 5-60 mm, and the thickness of the covering material being 0.5-5.0 mm.