Plated Steel T-Joint Geometry for Pore-Free Fillet Welding
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Solution Overview
Problem
Pore defects in weld beads of T-joints manufactured using zinc-based plated steel sheets, caused by vaporized zinc plating during welding, lead to reduced joint strength and appearance quality, and existing methods to mitigate these defects are either costly or insufficiently effective.
Innovation Solution
A T-joint design featuring a second steel sheet with a sheet thickness of 6.0 mm or less, where the end portion has an inclined surface forming an acute angle with the first steel sheet, and a valley section is provided on the side opposite to the weld bead to discharge plating vapor, thereby reducing pore defects and improving corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If zinc-based plated steel sheets are welded to manufacture T-joints, then corrosion resistance is improved, but pore defects occur in weld beads due to vaporized plating
Solution Approach 1:
The patent applies preliminary action by providing grooves in the joint region before welding occurs. These grooves are pre-formed to control the flow and discharge path of plating vapor during welding, preventing vapor entrapment that causes pore defects while preserving the corrosion-resistant zinc plating on the steel sheets
2Manufacturing precision
If complex machining methods are used to suppress pore defects, then weld bead quality is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The patent segments the joint region by providing multiple grooves that divide the welding area into controlled zones. This segmentation allows plating vapor to be channeled and discharged through specific paths defined by the grooves, effectively suppressing pore defects without requiring complex overall machining of the entire structure
Solution Approach 2:
The patent applies local quality by providing grooves only in the specific joint region where welding occurs, rather than machining the entire steel sheet. The grooves are localized to the abutting surface area, providing the necessary vapor discharge paths while minimizing unnecessary material removal and processing complexity
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 effectively suppresses pore defects under various welding conditions, maintains joint strength, and enhances corrosion resistance without increasing manufacturing complexity or costs.
Implementation Method 1
the zinc-based plating of a steel sheet surface is vaporized by welding heat. The vaporized zinc-based plating, i.e. plating vapor forms bubbles in weld metal.
Data Source
AI summary
According to one aspect of the present invention, there is provided a T-joint including a first steel sheet, a second steel sheet, and a fillet welded part, in which the sheet thickness of the second steel sheet is 6.0 mm or less, the second steel sheet is stood on a first surface of the first steel sheet, the fillet welded part joins the first surface of the first steel sheet and a first surface of the second steel sheet to each other, at least one of the first surface of the first steel sheet or the first surface of the second steel sheet includes a zinc-based plating, an abutting end portion of the second steel sheet on a second surface side of the second steel sheet has an inclined surface, and in a cross section taken along a sheet thickness direction of the first steel sheet and a sheet thickness direction of the second steel sheet, the inclined surface forms an acute angle with respect to the first surface of the first steel sheet.