Duplex Stainless Clad Steel Without Solution Heat Treatment
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Solution Overview
Problem
The existing production processes for hot rolled duplex stainless steel materials and clad steel plates require solution heat treatment, which degrades toughness and corrosion resistance, and are energy-intensive, making them costly and environmentally inefficient.
Innovation Solution
A method for producing alloying element-saving hot rolled duplex stainless steel materials and clad steel plates without solution heat treatment, by controlling the chemical composition and hot working conditions to suppress chromium nitride precipitation, thereby maintaining strength, impact property, and corrosion resistance, and reducing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solution heat treatment is carried out at high temperature (1000°C or higher) to solid-solubilize precipitates, then corrosion resistance is improved, but energy consumption increases and manufacturing cost increases
Solution Approach 1:
The invention changes the chemical composition parameters of the steel material by adding specific amounts of Ti (0.01-0.05 mass%) and controlling Cr (17-23 mass%), C (0.03-0.10 mass%), and N (0.06-0.15 mass%) contents. This parameter change suppresses chromium nitride precipitation during hot rolling, eliminating the need for solution heat treatment and thereby reducing energy consumption while maintaining corrosion resistance.
Solution Approach 2:
The invention performs preliminary action by adding Ti element before hot rolling to suppress chromium nitride precipitation during the hot rolling process itself. This preliminary suppression of precipitation eliminates the need for subsequent solution heat treatment, achieving both energy savings and maintained material properties.
2Reliability
If solution heat treatment is carried out to solid-solubilize precipitates, then corrosion resistance is improved, but toughness degrades
Solution Approach 1:
The invention changes the chemical composition parameters by adding Ti (0.01-0.05 mass%) and controlling Cr, C, and N contents to suppress chromium nitride precipitation. By preventing precipitation during hot rolling through composition control, the invention avoids the need for solution heat treatment that would otherwise degrade toughness, thereby maintaining both corrosion resistance and toughness.
Solution Approach 2:
The invention performs preliminary suppression of chromium nitride precipitation during hot rolling through specific alloying (Ti addition), preventing the formation of precipitates that would later require dissolution via solution heat treatment. This preliminary action preserves the matrix structure and maintains toughness while ensuring corrosion resistance.
3Reliability
If alloying elements (Ni, Mo, Cr) are increased to improve corrosion resistance, then corrosion resistance is improved, but manufacturing cost increases
Solution Approach 1:
The invention optimizes the parameter range of alloying elements: Cr (17-23 mass%), Ni (0.5-5.0 mass%), and Mo (0.1-1.0 mass%). Within these ranges, corrosion resistance is maintained while avoiding excessive alloying. The key innovation is adding Ti (0.01-0.05 mass%) to suppress precipitation, which allows cost-effective alloy compositions without requiring expensive high-alloy formulations.
Solution Approach 2:
The invention uses a small amount of Ti (0.01-0.05 mass%), which is relatively inexpensive, to achieve the effect of suppressing chromium nitride precipitation. This small addition of Ti replaces the need for more expensive high-alloy formulations or energy-intensive heat treatment processes, providing a cost-effective solution.
4Ease of manufacture
If chromium nitride precipitation is allowed to occur, then manufacturing process is simplified, but impact property degrades and corrosion resistance degrades
Solution Approach 1:
The invention changes the chemical composition parameters by adding Ti (0.01-0.05 mass%) and controlling Cr (17-23 mass%), C (0.03-0.10 mass%), and N (0.06-0.15 mass%) contents. This parameter change suppresses chromium nitride precipitation during hot rolling, maintaining impact property and corrosion resistance while keeping the manufacturing process simple and energy-efficient.
Solution Approach 2:
The invention introduces Ti as an intermediary element that suppresses chromium nitride precipitation. Ti acts as a mediator by forming TiN instead of CrN, preventing chromium depletion and maintaining both impact property and corrosion resistance without requiring complex post-processing heat treatments.
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 approach results in materials that are thinner, stronger, and more cost-effective, with improved toughness and corrosion resistance, suitable for applications like seawater desalination instruments and shipping vessel tanks, while minimizing environmental impact.
Implementation Method 1
controlling the chemical composition and hot working conditions to suppress chromium nitride precipitation, thereby maintaining strength, impact property, and corrosion resistance
Implementation Method 2
a method for producing alloying element-saving hot rolled duplex stainless steel materials and clad steel plates without solution heat treatment, by controlling the chemical composition and hot working conditions
Data Source
AI summary
The present invention refers to a clad steel plate comprising: a steel plate of a base metal; and a steel plate of a cladding material joined to either or both of two main surfaces of the steel plate of the base metal by hot rolling, wherein the cladding material consists of a duplex stainless steel, the duplex stainless steel contains, by mass%: C: 0.03% or less; Si: 0.05% to 1.0%; Mn: 0.5% to 7.0%; P: 0.05% or less; S: 0.010% or less; Ni: 0.1% to 5.0%; Cr: 18.0% to 25.0%; N: 0.05% to 0.30%; and Al: 0.001% to 0.05%, and further contains one or more selected from: V: 0.05% to 0.5%; Nb: 0.01% to 0.20%; and Ti: 0.003% to 0.05%, with a remainder being Fe and inevitable impurities, and a chromium nitride precipitation temperature TN2, which is a second index regarding precipitation of chromium nitrides during the hot rolling, is in a range of 800 C to 970 C.