Variable Wall Thickness Rocket Extension Section Forming
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Solution Overview
Problem
The challenge lies in forming a large-sized variable wall thickness extension section of a liquid rocket engine using high-temperature alloy GH3044, which is difficult to control in the spin forming process due to its unique dimensions and material properties, leading to high costs and long delivery times for customized components.
Innovation Solution
A method involving electron beam tailor welding to form a plate blank, followed by deep drawing, primary and secondary spin forming, and vacuum solid solution treatments to achieve the desired curved generatrix profile, ensuring precise control of welding seam strength and flatness, and adjusting spinning parameters for stable and reproducible results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-temperature alloy GH3044 is used for spin forming, then the extension section can be formed with required strength and temperature resistance, but the spinning properties are difficult to control leading to poor manufacturing precision
Solution Approach 1:
The extension section is divided into multiple segments that are welded together to form a complete structure. This segmentation allows each segment to be formed with controlled dimensions and properties, then assembled into the final large-scale component with variable wall thickness, resolving the contradiction between material strength requirements and spinning control difficulties.
Solution Approach 2:
Different segments are designed with locally optimized properties including varying wall thicknesses and material characteristics suited for specific regions of the extension section. This local quality approach enables precise control of spinning properties in different areas while maintaining overall structural strength and temperature resistance.
2Reliability
If commercially-available large-sized GH3044 with thickness 3.5 mm is customized, then the material can meet the extension section requirements, but the delivery time increases and cost increases
Solution Approach 1:
Instead of customizing one large-sized plate, the design uses multiple smaller standard-sized plates that can be welded together. These segmented plates can be sourced from standard inventory, eliminating long delivery times and customization costs while still achieving the required large-scale extension section with appropriate wall thickness distribution.
Solution Approach 2:
The wall thickness parameter is varied locally across different segments rather than using a uniform thick plate throughout. This allows the use of thinner, more readily available standard plates in regions where full thickness is not required, reducing material cost and delivery time while maintaining structural integrity through strategic thickening at critical locations.
3Ease of manufacture
If the extension section is made with uniform wall thickness, then manufacturing is simpler, but the actual design requires variable wall thickness with small-end 1.5 mm and large-end 0.65 mm
Solution Approach 1:
The extension section is divided into multiple segments, each with uniform wall thickness suitable for straightforward manufacturing. The variable wall thickness requirement is achieved by assembling segments with different thicknesses in appropriate locations, combining manufacturing simplicity with the required complex geometry.
Solution Approach 2:
Each segment is designed with uniform local properties optimized for its specific position in the assembly. The overall variable wall thickness profile is achieved through local quality variations across segments rather than through complex forming of a single uniform piece, simplifying manufacturing while meeting design requirements.
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 the production of a large-sized variable wall thickness extension section with precise dimensions and improved product quality, reducing the need for subsequent machining and minimizing processing risks, thus optimizing the manufacturing process.
Implementation Method 1
subjecting the two segments to electron beam welding to form a whole circle plate
Implementation Method 2
The two segments are subjected to electron beam welding to form the whole circle plate to obtain the plate blank
Implementation Method 3
followed by vacuum solid solution treatment
Implementation Method 4
subjecting the plate blank to deep drawing through a pre-forming mold to obtain a shallow dish-shaped blank
Implementation Method 5
subjecting the shallow dish-shaped blank to a primary spin forming to obtain a primary spin-formed blank
Data Source
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AI summary
A method for forming a large-sized variable wall thickness extension section of a liquid rocket engine by tailor welding and spinning is provided. High-temperature alloy GH3044 is subjected to laser numerical control machining to form two segments, which are welded by electron beam welding to obtain a plate blank, followed by vacuum solid solution treatment. The plate blank is pre-formed into a shallow dish-shaped blank, followed by vacuum solid solution treatment. The plate blank is assembled with a spinning mandrel of a primary spin-forming mold, and is subjected to primary spin forming to obtain a primary spin-formed blank, followed by vacuum solid solution treatment. The primary spin-formed blank is assembled with a spinning mandrel of a secondary spin-forming mold, and is subjected to secondary spin forming to obtain a curved generatrix extension section.