Welded Metal Pipe Forming with Die-Contact Cooling Control

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Solution Overview

Problem

In existing forming systems, metal pipes with welded portions are prone to breakage due to reduced deformation resistance at the welded areas when heated and expanded, leading to localized thinning and potential damage.

Innovation Solution

The system ensures the welded portion of the metal pipe contacts the die surface earlier during expansion, increasing deformation resistance through heat conduction cooling, and adjusts the welded portion's location relative to the pipe's center to distribute stress evenly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the metal pipe material is heated to expand it, then the pipe expansion rate increases, but the deformation resistance of the welded portion is reduced causing localized thinning and potential breakage

Engineering Contradiction:
Improvepipe expansion rateVSAvoiddeformation resistance of welded portion
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The welded portion is positioned to contact the die surface before the expansion process begins, so that cooling and strengthening occur in advance before the high-stress expansion phase

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The die surface is designed to contact specifically the welded portion at a different timing than other portions, creating localized cooling and strengthening exactly where the welded portion needs enhanced deformation resistance

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If the metal pipe material is heated uniformly, then the expansion process is simplified, but the welded portion experiences excessive softening and thinning

Engineering Contradiction:
Improveheating process simplicityVSAvoidplate thickness uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The welded portion is pre-cooled by die contact before expansion, compensating for the excessive heat softening that occurs during uniform heating

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The welded portion is quickly cooled by die contact to skip through the dangerous temperature range where deformation resistance is too low, preventing thinning before it can occur

Inventive Principle:
Principle #21Skipping (Rushing through)

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 effectively suppresses localized thinning and breakage at the welded portion by enhancing deformation resistance, ensuring stable pipe formation.

Implementation Method 1

the portion which is in contact with the die is cooled due to heat conduction, and thus the deformation resistance of the portion increases

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Data Source

PatentEP3603838B1Molding system and molding method
Publication Date: 2025.06.25 SUMITOMO HEAVY IND LTD
  • EP3603838B1 patent drawingFigure 1
  • EP3603838B1 patent drawingFigure 2
  • EP3603838B1 patent drawingFigure 3

AI summary

A forming system is for forming a metal pipe from a cylindrical metal pipe material having a welded portion in which end portions of a plate material are welded to each other. The forming system includes: a forming apparatus which includes a set of dies and a heating and expanding part which heats and expands a metal pipe material disposed between the dies; a supply device which supplies the metal pipe material to the forming apparatus; and a control device which controls an operation of the supply device. The control device includes a storage unit which stores information on a longest position which is a position at which a distance from a center of the metal pipe material is the longest, on a surface of the die, in a case of being viewed from an extension direction of the metal pipe material in a state where the metal pipe material is disposed between the dies, and a control unit which controls, based on the information on the longest position stored in the storage unit, supply of the metal pipe material to the forming apparatus by the supply device such that the welded portion is not located on a straight line connecting the longest position and the center of the metal pipe material in a case of being viewed from the extension direction in a state where the metal pipe material is disposed between the dies.