Steel Yankee Cylinder External Butt Welding With Single-Pass Fusion
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Solution Overview
Problem
The existing methods for manufacturing steel Yankee cylinders require hazardous and demanding welding conditions due to high temperatures and the need for internal welding, posing risks to operators and necessitating extensive ventilation.
Innovation Solution
A method where a cylindrical shell is welded to two end walls using a circumferential butt weld from the outside, employing a backing material to ensure a single, complete weld bead that fuses the surfaces, eliminating the need for internal welding and reducing ventilation requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If welding is performed from the inside of the Yankee cylinder, then the weld quality meets pressure vessel requirements, but the working conditions become hazardous and demanding with high temperatures and ventilation requirements
Solution Approach 1:
The patent inverts the conventional welding approach by performing welding exclusively from the outside of the Yankee cylinder instead of from the inside. This reversal eliminates the hazardous working conditions (high temperatures, ventilation requirements) while maintaining weld quality through the use of backing material and single-pass welding technique
2Reliability
If welding is performed from the inside of the Yankee cylinder, then the weld quality meets pressure vessel requirements, but extensive ventilation is required during the welding operation
Solution Approach 1:
The patent eliminates the need for extensive ventilation by inverting the welding approach and performing welding exclusively from the outside. This removes the source of harmful fumes from the worker environment while maintaining pressure vessel quality standards through proper welding technique and backing material
3Reliability
If multiple weld passes are used to ensure complete fusion, then the weld quality is improved, but the welding time and complexity increase
Solution Approach 1:
The patent applies preliminary action by preparing the joint geometry and positioning backing material before welding. This allows the weld to be completed in a single pass with complete penetration, eliminating the need for multiple passes and reducing welding time while maintaining quality
Solution Approach 2:
The patent changes the welding parameters by using a single-pass technique with specific amperage, voltage, and travel speed settings that achieve complete fusion in one pass. The backing material enables this parameter change by supporting the molten pool and ensuring full penetration without requiring multiple passes
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 approach reduces the operational hazards for welders, minimizes ventilation needs, and simplifies the welding process by completing the weld from the outside, resulting in a safer and faster production of steel Yankee cylinders.
Implementation Method 1
a cylindrical shell is welded to two end walls using a circumferential butt weld
Implementation Method 2
a single weld bead is formed that extends all the way between the opposing surfaces and completely fuses the opposing surfaces
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a method of making a steel Yankee cylinder 1 by welding a cylindrical shell 2 to two end walls 3, 4 such that the cylindrical shell 2 and the end walls 3,4 together form the Yankee cylinder 1. The welding operation is carried out exclusively from the outside of the Yankee cylinder 1 and in the welding operation is carried out as a butt welding operation in which a backing material 7 is used on the inside of the Yankee cylinder 1 such that, between each end wall 3, 4 and the cylindrical shell 1, a single weld bead 8 is formed which extends all the way between the opposing surfaces 5, 6 and completely fuses the opposing surfaces 5, 6 of each end wall 3, 4 and the cylindrical shell 2 respectively.