Clad Steel Billet Scavenging Metal Segmentation
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Solution Overview
Problem
The production of corrosion-resistant metal products with a stainless steel or alloy cladding and a carbon steel core faces issues such as oxidation at the interface, weld failure, and deformation during rolling, particularly with larger square billets, due to the reactivity of scavenging metals like titanium and aluminium at elevated temperatures.
Innovation Solution
The billet design includes a steel body with a formation, such as a cavity, to separate the scavenging metal from the cladding member, using a barrier element to prevent contact and oxidation, and employing a method where the cladding tube is swaged and welded to the core to enhance bonding and structural integrity during rolling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If scavenging metal is placed in the cladding tube to prevent oxidation, then oxidation resistance is improved, but weld reliability deteriorates due to reactivity at elevated temperatures
Solution Approach 1:
The cladding tube is divided into multiple sections with scavenging metal placed in specific locations (at the ends and/or in the middle section), rather than uniformly distributed. This segmentation allows oxidation protection where needed while minimizing interference with weld zones.
Solution Approach 2:
A barrier element is introduced as an intermediary between the scavenging metal and the cladding tube wall. This barrier prevents direct contact and reactive bonding between the scavenging metal and cladding material during welding, eliminating the harmful effect while preserving the oxidation-scavenging function.
2Object-affected harmful factors
If scavenging metal is activated at high temperature to scavenge oxygen, then oxidation protection is improved, but harmful reactions with cladding metal increase
Solution Approach 1:
The barrier element serves as a mediator that allows the scavenging metal to activate and scavenge oxygen at high temperatures while preventing direct contact with the cladding metal, thus eliminating harmful reactive bonding.
Solution Approach 2:
The barrier element is strategically positioned only where scavenging metal contacts the cladding tube, providing localized protection against reactive bonding while allowing other areas to maintain their original properties.
3Productivity
If larger square billets are used to meet production demands, then productivity is improved, but deformation and finning during rolling increase
Solution Approach 1:
The billet is segmented into core and cladding components with the cladding tube swaged to fit over the core. This segmented construction with interlocking surfaces provides better dimensional control during rolling of larger billets, reducing finning and deformation while maintaining high productivity.
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
This approach reduces the likelihood of weld failure, oxidation, and deformation, ensuring the production of stable, corrosion-resistant ferrous products by maintaining the scavenging metal out of contact with the cladding, thus preventing destructive reactions and enhancing the structural integrity of the billet during processing.
Implementation Method 1
The root of the problem is the occurrence of oxidation at elevated temperatures of the chrome in the stainless steel at the interface between the cladding and steel core
Implementation Method 2
The scavenging metal serves to scavenge oxygen and all other gases except inert gases from residual air at the interface
Implementation Method 3
a barrier element to prevent contact and oxidation
Implementation Method 4
employing a method where the cladding tube is swaged and welded to the core to enhance bonding and structural integrity during rolling
Data Source
AI summary
Billets and methods for manufacturing them are disclosed. The billets include a cladding member including an alloy selected from the group including stainless steel, nickel-chrome, nickel-copper, and copper-nickel alloys, and a steel body that is positioned so that it has an interface with the cladding member, the steel body having a formation in which the scavenging metal is located and elements being provided for separating the scavenging metal from the cladding member at the interface.