Thin-Walled Ring Shell Forming with Local Thermal Expansion
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Solution Overview
Problem
Current methods for manufacturing large-size thin-walled ring shells result in poor surface quality, low dimensional accuracy, microstructural defects, and degradation of mechanical properties due to excessive weld seams, and are inefficient with high requirements for die size and equipment, leading to material waste and defects like wrinkling and cracking.
Innovation Solution
An integral forming method involving analysis of the target part's characteristics to determine the optimal billet shape and size, followed by roll welding, bending, and local thermal expansion forming to minimize deformation and weld seams, with subsequent cutting to eliminate process segments and achieve high accuracy and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If segmented stamping forming and welding is used to manufacture large-size thin-walled ring shells, then the forming process is feasible, but the surface quality deteriorates, dimensional accuracy decreases, and microstructural defects occur due to excessive weld seams
Solution Approach 1:
The patent divides the forming process into multiple stages: first forming a cylindrical intermediate product, then performing localized thermal expansion forming to create the final ring shell shape. This segmentation allows each stage to be optimized independently, avoiding the need for excessive weld seams while maintaining forming feasibility.
Solution Approach 2:
The patent utilizes thermal expansion by heating the metal billet to elevated temperatures before forming. This parameter change (temperature increase) reduces the material's flow stress and increases ductility, enabling complex shape changes without cracking and improving surface quality while reducing the need for weld repairs.
2Reliability
If traditional sheet metal stamping forming is used for integral structure, then weld seam issues are eliminated, but the deformation exceeds the forming limit and integral forming cannot be achieved
Solution Approach 1:
The patent applies thermal expansion by heating the billet to high temperatures before forming operations. This parameter change fundamentally alters the material's mechanical properties, increasing ductility and reducing flow stress, which allows the material to undergo large deformations without exceeding its forming limit, thereby achieving integral structure with high reliability.
Solution Approach 2:
The patent performs preliminary cylindrical forming before the final ring shell shaping. This preliminary action creates an intermediate structure that is more stable and easier to control during subsequent thermal expansion forming, preventing excessive deformation and ensuring the forming process remains within material limits.
3Reliability
If large-size dies and forming equipment are used for integral deep drawing or superplastic forming, then integral structure is achieved, but cost increases and efficiency decreases
Solution Approach 1:
The patent segments the forming process into distinct stages (cylindrical forming, thermal expansion, final shaping) that can be performed using smaller, more accessible equipment. This eliminates the need for large-size dies and specialized forming equipment, improving productivity while maintaining integral structure reliability.
Solution Approach 2:
By utilizing thermal expansion parameters, the patent enables forming operations with conventional equipment rather than requiring specialized large-size forming equipment. The temperature-dependent material properties allow standard machinery to achieve results that would otherwise require expensive, specialized equipment, thereby improving efficiency.
4Manufacturing precision
If extensive edge compression and process segments are added to alleviate forming defects, then forming quality improves, but raw material waste increases due to cutting requirements
Solution Approach 1:
The patent uses thermal expansion parameters to achieve forming quality improvements without requiring extensive edge compression or additional process segments. The heated material's enhanced ductility allows direct forming of the final shape with minimal material removal, significantly reducing raw material waste compared to conventional cold forming methods.
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 reduces the number of weld seams, minimizes deformation risks, and achieves high forming accuracy and efficiency with smaller, less costly dies, improving material utilization and service performance of thin-walled ring shells.
Implementation Method 1
local thermal expansion forming
Data Source
AI summary
The present invention belongs to the technical field of metal forming manufacturing and discloses an integral forming method for a large-size thin-walled ring shell. The integral ring shell obtained by the forming method of the present invention has only one circumferential weld seam and one radial weld seam. If the two weld seams are located in an excisable process segment region, the target part without weld seams can be obtained after the process segment is cut off. The forming method of the present invention adopts a local thermal expansion forming method, plastic deformation occurs only in mold-constrained high temperature regions in a single local forming process, and a part with each region meeting the requirements can be obtained after several local thermal expansion forming processes. The forming method of the present invention can obtain two open cross-sectional ring shell components or multiple segmented ring shell components at one time.