Hot-Press Soldering of Coated Metal Sheets Without Weld Damage
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Solution Overview
Problem
Conventional welding techniques for joining hot-stamped components made of quenched and tempered steel result in material damage, and existing methods for producing joining connections between metal sheets in vehicle body construction are complex and costly, requiring separate forming and joining processes.
Innovation Solution
A method involving hot-press soldering with pretreatment of the metal sheets to break up scaling-resistant coatings, allowing for a planar connection between coated, hot-worked metal sheets during the hot-working process, using mechanical or laser tools to expose the metal surfaces for optimal solder application and energy input for soldering, thereby eliminating air gaps and enhancing load-bearing capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional welding techniques are used to join hot-stamped components, then the components can be connected, but material damage occurs
Solution Approach 1:
The patent changes the joining method from welding to hot-press soldering, which operates at lower temperatures and avoids the material damage caused by conventional welding. The soldering process uses a eutectic solder alloy that melts at a specific temperature range, allowing joining without damaging the hot-stamped steel components.
Solution Approach 2:
The patent introduces a zinc-based solder as an intermediary material between the two steel components. This solder layer facilitates the joining process by providing a ductile bonding interface that avoids direct metal-to-metal contact and heat-affected zone damage that would occur with welding.
2Reliability
If separate forming and joining processes are used, then each process can be optimized, but the manufacturing process becomes complex and costly
Solution Approach 1:
The patent merges the forming and joining processes into a single integrated hot-press soldering operation. The components are formed and joined simultaneously in one die set, eliminating the need for separate forming and joining equipment, reducing manufacturing complexity and cost.
Solution Approach 2:
The die set is designed to perform multiple functions: it forms the steel components through hot stamping and simultaneously creates the joining connection through hot-press soldering. This multi-functional tooling reduces the number of required equipment pieces and simplifies the manufacturing process.
3Object-affected harmful factors
If scaling-resistant coatings are applied to metal sheets, then oxidation resistance is improved, but soldering becomes difficult
Solution Approach 1:
The patent applies a zinc-based pretreatment coating to the steel sheets before hot-press soldering. This preliminary coating creates a reactive zinc layer that facilitates solder wetting and bonding, allowing the soldering process to proceed effectively while maintaining oxidation resistance during storage and handling.
Solution Approach 2:
The patent uses a composite coating system consisting of multiple layers: a scaling-resistant outer layer for oxidation protection and a zinc-based inner layer for soldering promotion. This composite structure allows the metal sheet to benefit from both oxidation resistance and solderability.
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 simplifies the manufacturing process, reduces material damage, and enhances the load-bearing capacity of the connection under shear and peel forces, while avoiding the need for additional welding and reducing tool wear and heat transfer issues.
Implementation Method 1
a first metal sheet (1, 2) and a second metal sheet (1, 2) are heated to a temperature between 700° C. and 950° C.
Implementation Method 2
a solder material (5) is applied to at least one of the first metal sheet (1, 2) and the second metal sheet (1, 2) in a subregion (1a, 2a) used for the connection
Data Source
AI summary
A method for producing a joining connection between at least two metal sheets or at least two components made of hot-workable sheet metal with a scaling-resistant coating, is provided. The method includes at least one step in which a connection is produced between the at least two metal sheets or sheet-metal components by hot-press soldering, wherein the surface of the metal sheets or components to be connected is pretreated in order to break up the coating.