Cylindrical Member Joining with Pre-Grooving After Roller Bending

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Solution Overview

Problem

The existing methods for manufacturing core barrels in nuclear reactors face challenges in achieving accurate joining of thick plate materials due to deformation during roller bending, leading to difficulties in electron-beam welding and resulting in low-quality cylindrical members.

Innovation Solution

A method involving end bending, primary grooving, bending into a ring shape, secondary grooving, and electron beam welding of the plate material's end portions to ensure precise alignment and minimize deformation, allowing for high-quality cylindrical member production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If thick plate material is subjected to roller bending to form a ring shape, then the cylindrical member can be manufactured, but the joining surface of each end portion deforms making highly accurate joining difficult

Engineering Contradiction:
Improvecylindrical member formationVSAvoidjoining surface accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by performing grooving operations on the end portions before the final joining process. The grooves are created in advance to compensate for and control the deformation that occurs during roller bending, ensuring that the joining surfaces remain accurate despite the bending process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the physical parameters of the end portions by creating grooves with specific dimensions and geometries. These parameter changes in the end portion structure allow for compensation of deformation and enable precise joining even after roller bending has caused some distortion.

Inventive Principle:
Principle #35Parameter changes

2Strength

If end portions are joined by electron-beam welding, then strong joining is achieved, but deformation of the joining surface prevents highly accurate joining

Engineering Contradiction:
Improvejoining strengthVSAvoidjoining accuracy
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The grooving operation is performed as a preliminary action before electron-beam welding to pre-position and stabilize the end surfaces. This preliminary grooving ensures that when electron-beam welding is applied for strong joining, the surfaces remain properly aligned and accurate despite the intense heat and potential deformation from the welding process.

Inventive Principle:
Principle #10Preliminary action

3Shape

If roller bending is used to form the plate material into a ring, then the cylindrical shape is achieved, but the end surfaces become non-parallel reducing joining quality

Engineering Contradiction:
Improvecylindrical shapeVSAvoidend surface parallelism
Core Design Contradiction:
ShapeVSManufacturing precision

Solution Approach 1:

The patent changes the geometric parameters of the end surfaces by creating grooves that compensate for the non-parallelism introduced by roller bending. The groove dimensions and positions are specifically designed to restore parallelism between the end surfaces, enabling high-quality joining while maintaining the required cylindrical shape.

Inventive Principle:
Principle #35Parameter changes

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 accurate and deformation-free joining of the plate material's end portions, resulting in a high-quality cylindrical member with reduced welding distortion and improved manufacturing precision.

Implementation Method 1

ending portions of a plate material are joined by electron beam welding

Methodology Applied
Scientific EffectElectron beam welding: Electron Beam

Data Source

PatentEP3170575B1Method for manufacturing cylindrical member
Publication Date: 2022.08.31 MITSUBISHI HEAVY IND LTD
  • EP3170575B1 patent drawingFigure 1~2
  • EP3170575B1 patent drawingFigure 3~4
  • EP3170575B1 patent drawingFigure 5~6

AI summary

Provided is a method for manufacturing a cylindrical member which includes end bending (S11) of respective end portions of a plate material (101) in a longitudinal direction, primary grooving (S12) of respective end surfaces of the plate material (101) subjected to end bending, bending (S13) of the plate material (101) to a ring shape, secondary grooving (S14) of respective end surfaces (103, 104) of the plate material (101) subjected to bending in a ring shape, and joining (S15) of respective end surfaces (104) of the plate material (101). Therefore, it is possible to manufacture a high-quality cylindrical member.