Wide Steel Sheet Welding Without Filler for Surface and Strength
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Solution Overview
Problem
The production of wide and thin steel sheet products is challenging due to high production costs and inferior surface quality and thickness tolerances in existing rolling mills, which limits their application in heavy-duty vehicles and other demanding uses.
Innovation Solution
A method involving the cleaning of longitudinal edges, butt welding of steel sheets without filler material under inert gas protection, followed by heat treatment and quenching to produce high-strength steel sheets with improved surface quality and thickness uniformity, allowing for the production of wide steel sheets with enhanced bendability and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If Steckel rolling mills or heavy plate rolling mills are used to produce wide and thin steel sheets, then the production capability for wide steel sheets is achieved, but the production rate decreases significantly and surface quality and thickness tolerances become inferior
Solution Approach 1:
The steel sheet is divided into multiple narrower steel sheets that are produced separately using high-speed strip rolling mills, then joined together through welding to form a wide steel sheet product. This segmentation allows the use of efficient narrow-strip rolling technology while achieving wide final product dimensions.
Solution Approach 2:
Multiple narrow steel sheets are merged together through welding to create a wide steel sheet product. This combining approach enables the production of wide sheets using efficient narrow-strip rolling technology, avoiding the productivity penalties of using heavy plate rolling mills for wide sheets.
2Area of stationary object
If Steckel rolling mills or heavy plate rolling mills are used to produce wide and thin steel sheets, then the production capability for wide steel sheets is achieved, but surface quality and thickness tolerances become inferior
Solution Approach 1:
The steel sheet is divided into multiple narrower steel sheets that are produced separately using high-speed strip rolling mills, then joined together through welding to form a wide steel sheet product. This segmentation allows the use of efficient narrow-strip rolling technology while achieving wide final product dimensions.
Solution Approach 2:
Different regions of the final wide steel sheet (the individual narrow sheets before welding) are produced with high local quality using optimized strip rolling parameters, ensuring excellent surface quality and thickness tolerances in each segment that collectively form the wide product.
3Ease of manufacture
If welding is performed without inert gas protection on both top side and root side, then the welding process is simpler and faster, but grain boundary ferrite forms in the weld area reducing strength and bendability
Solution Approach 1:
Inert gas protection is applied during welding to create an inert atmosphere that prevents oxidation and controls the weld microstructure, specifically preventing grain boundary ferrite formation and ensuring a martensitic structure for high strength and good bendability.
4Strength
If filler material is used in butt welding, then the weld strength is improved, but the chemical composition uniformity across the weld is compromised and excess material removal is required
Solution Approach 1:
Filler material is extracted from the welding process, using instead a fillerless welding technique that joins the steel sheets without adding external material, thereby maintaining chemical composition uniformity across the weld while still achieving the required strength through proper welding parameters and inert gas protection.
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 method enables cost-efficient production of wide steel sheets with improved surface quality, thickness tolerances, and high strength, suitable for heavy-duty applications, by preventing grain boundary ferrite formation and maintaining chemical composition uniformity across the weld.
Implementation Method 1
inert gas protection is applied on both a top side and a root side of the weld during welding, thereby preventing grain boundary ferrite formation in the area of the weld
Implementation Method 2
hardening of the welded steel sheet product by means of heat treatment and subsequent quenching
Implementation Method 3
hardening of the welded steel sheet product by means of heat treatment and subsequent quenching
Implementation Method 4
joining the steel sheets along the cleaned longitudinal edges using butt welding without filler material to form a weld
Data Source
AI summary
A steel sheet product and a method for manufacturing the steel sheet product are described, the method includes the steps:providing at least two steel sheets extending in a longitudinal direction (A),cleaning longitudinal edges of the steel sheets by removing any surface oxide layers therefrom,joining the steel sheets along the cleaned longitudinal edges using butt welding without filler material to form a weld, wherein inert gas protection is applied on both a top side and a root side of the weld during welding, thereby obtaining a welded steel sheet product,removal of excess material from the weld, andhardening of the welded steel sheet product by means of heat treatment and subsequent quenching.