Galvanized Metal Sheet Forming Process for Corrosion Protection
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Solution Overview
Problem
Current manufacturing processes for galvanized steel objects with complex shapes face challenges such as corrosion protection issues due to zinc-free cutting edges and the inability to form thin sheets without cracking the galvanizing coating, limiting the production of high-quality, corrosion-resistant three-dimensional objects with multiple edges.
Innovation Solution
A process involving pre-cutting metal sheets with multiple free edges, followed by batch hot dipping in a molten zinc alloy bath and subsequent cold-forming to create complex shapes without compromising the zinc coating, allowing for non-thermal joining of metal edges and preventing corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If welding is used to join galvanized steel sheets, then strong bonding is achieved, but zinc fumes are generated causing metal fume fever
Solution Approach 1:
The patent replaces thermal welding processes with mechanical clinching processes to join galvanized steel sheets. The clinching process uses localized plastic deformation to create interlocking joints without melting or burning the zinc coating, thereby eliminating zinc fume generation while maintaining strong bonding strength through mechanical interlocking and cold-forming effects.
2Shape
If cutting is performed on galvanized metal sheets, then complex shapes are achieved, but zinc-free cutting edges are created compromising corrosion protection
Solution Approach 1:
The patent performs galvanizing as a preliminary step before cutting operations. By applying the zinc coating to the metal sheets first, then subsequently cutting them into complex shapes, the process ensures that the majority of surfaces maintain corrosion protection. The preliminary galvanizing action establishes the protective layer that can then be selectively removed only where necessary for forming the final shape.
3Shape
If thin metal sheets are cold-formed after galvanizing, then complex three-dimensional shapes are achieved, but cracks in the zinc coating occur
Solution Approach 1:
The patent reverses the conventional sequence by performing cold-forming operations before galvanizing. The metal sheets are first shaped into complex three-dimensional forms through bending and folding, and only then is the zinc coating applied. This preliminary forming action eliminates subsequent coating cracks because the shaping operations are completed while the material is still in its original state, before the brittle zinc layer is deposited.
Solution Approach 2:
The patent changes the process parameter sequence by inverting the traditional order of operations. Instead of galvanizing then forming, the process applies forming then galvanizing. This parameter change in process sequencing fundamentally resolves the coating crack issue by ensuring all deformation occurs before the brittle zinc layer is introduced to the system.
4Reliability
If galvanizing is performed after forming complex shapes, then corrosion protection is achieved, but transportation space and time are increased
Solution Approach 1:
The patent performs galvanizing as a preliminary action on flat metal sheets before they are formed into complex three-dimensional shapes. By applying the protective zinc coating to the flat sheets in advance, the process eliminates the need for subsequent galvanizing operations on finished complex shapes, thereby reducing transportation space requirements and processing time while ensuring corrosion protection is established on all surfaces before final shaping.
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 ensures full corrosion protection, enables the production of high-quality, lightweight, and mechanically resistant galvanized steel objects with complex shapes, and reduces manufacturing costs by avoiding the limitations of prior art techniques.
Implementation Method 1
batch hot dipping said metal sheet matrix into a molten zinc alloy galvanizing bath
Data Source
AI summary
This invention provides process for manufacturing a galvanized metal three-dimensional object with a shape including multiple edges, said process comprising, in the following order, the steps of: (A) providing and cutting a metal sheet matrix with a thickness within a range from 0.8 mm to 6 mm, the shape of said metal sheet matrix including multiple free edges, (B) batch-wise hot dipping said metal sheet matrix into a molten zinc alloy galvanizing bath, (C) cold-forming the galvanized metal sheet matrix into a desired three-dimensional shape including multiple adjacent metal edges, and (D) cold-forming a series of joining points for fastening together said multiple adjacent metal edges, to form said galvanized metal three-dimensional object.