Thick-Walled Metal Tube Rolling for Single-Pass Precision Forming
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Solution Overview
Problem
Existing methods for producing medium-small-aperture thick-wall metal tubes face inefficiencies in production efficiency, high costs, and poor surface and dimensional accuracy due to complex equipment and processes like extrusion, rotary forge mills, and three-roller skew rolling mills.
Innovation Solution
A composite forging and rolling method that includes induction heating and single-pass processing, allowing for large deformation amounts with high dimensional accuracy and improved surface quality, applicable to both cold and hot forming of various metal tubes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If extrusion forming is used to produce medium-small-aperture thick-wall metal tubes, then the production efficiency is low and product cost is high, but the method can produce very few metal tubes which cannot be or are difficult to produce by other processes
Solution Approach 1:
The patent changes the forming parameters by using hot rolling at elevated temperatures (800-1200°C) to enable large deformation amounts in a single pass, achieving high productivity while maintaining the ability to produce special medium-small-aperture thick-wall metal tubes that are difficult to manufacture by other processes
2Device complexity
If a two-roller pilger mill is used for rolling, then the structure is simple, but the stability of the rolling process is poor, dimensional accuracy is low and surface quality is poor due to reciprocating movement and large inertia
Solution Approach 1:
The patent segments the rolling process into multiple small incremental passes instead of single large deformations, with each pass producing small deformation amounts. This allows the use of a simple two-roller pilger mill structure while achieving high dimensional accuracy (±0.2mm) and good surface quality through cumulative small deformations
Solution Approach 2:
The patent employs dynamic adjustment of rolling parameters including variable cross-section roll-passes and adjustable rolling speeds, enabling the simple two-roller structure to adapt to different tube specifications and achieve stable, high-precision rolling without complex equipment
3Shape
If a three-roller skew rolling mill is used, then the tube blank can be reduced in diameter and wall thickness, but the surface quality is influenced by spiral lines and triangular defects appear at the tail part
Solution Approach 1:
The patent extracts and eliminates the skew rolling mechanism that causes spiral lines and triangular defects, using instead a conventional two-roller pilger mill with parallel rollers. This removes the source of surface defects while achieving the required diameter and wall thickness reduction through controlled rolling passes
4Shape
If a three-roller tension reducing mill with more than 10 racks is used, then hollow reducing of the tube blank can be completed, but the equipment investment is large, production line is long, occupied area is large and equipment adjustment and control are complicated
Solution Approach 1:
The patent merges multiple separate rack units into a single integrated two-roller pilger mill system. By combining the functions of multiple racks into one rolling unit with variable cross-section roll-passes, it achieves the same hollow reducing capability with significantly reduced equipment complexity, shorter production line, and simpler control
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 method achieves high dimensional accuracy (±0.2mm), good surface quality, and reduced equipment investment through single-pass processing, suitable for producing medium-small-aperture thick-wall metal tubes with various materials.
Implementation Method 1
the blank is heated to a target temperature, preferably of 800° to 1200°C, through an induction heating device
Data Source
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AI summary
The invention discloses a small-aperture thick-wall metal tube and a preparation method thereof. The cross-sectional diameter of the metal tube ranges from 30mm to 160mm, the dimensional accuracy is ±0.2mm, and the ratio of the outer diameter of the metal tube to the wall thickness of the metal tube is greater than 2 to less than or equal to 20. The inner wall and outer wall of the metal tube are free of peeling, dents, or cracks. The metal tube is made of steel, copper, aluminum, magnesium, titanium, or alloy. The invention has the characteristics of forging and rolling, can realize single pass and large deformation amount processing of the metal tube blank, and has the advantages of short process flow, high product dimensional accuracy (±0.2mm), good quality of the inner wall and outer wall surface, and low cost.