Pipe Weld Distortion Correction via Reference Surface Measurement

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Solution Overview

Problem

Weld distortion in the weld portion between a raw pipe and a fitting member installed at its axial end is challenging to correct due to the lack of a measurement reference on the raw pipe, making it difficult to accurately measure and correct the tilt of the fitting member with respect to the axial direction of the pipe.

Innovation Solution

A distortion correction method involving the formation of a circumferential reference surface on the rod-like member, allowing for accurate measurement and correction of the tilt using a dial gauge, and employing high-density energy welding such as electron beam or TIG welding to shape the weld beads and correct the distortion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If welding is performed between a fitting member and a raw pipe without a reference surface, then the welding process can be completed, but the tilt of the fitting member cannot be accurately measured due to lack of measurement reference

Engineering Contradiction:
Improvemeasurement accuracy of fitting member tiltVSAvoidcomplexity of measurement system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

A reference surface is formed on the outer circumference of the raw pipe before the fitting member is welded to it. This preliminary action creates a measurement reference that enables accurate tilt measurement of the fitting member after welding, without requiring complex measurement systems.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If a reference surface is formed on the rod-like member, then accurate measurement of fitting member tilt becomes possible, but additional manufacturing steps are required

Engineering Contradiction:
Improvetilt measurement accuracyVSAvoidmanufacturing process simplicity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The reference surface is formed in advance on the rod-like member before assembly and welding. This preliminary preparation enables subsequent accurate measurement of the fitting member's tilt relative to the rod-like member's axial direction, facilitating precise distortion correction.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The reference surface acts as an intermediary element between the rod-like member and the measurement device. It provides a stable, measurable surface that mediates the measurement process, allowing the dial gauge to accurately measure the tilt of the fitting member relative to the rod-like member's axial direction.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If TIG welding is used to correct weld distortion, then the weld bead can be heated and reshaped, but the process requires precise control of heating conditions

Engineering Contradiction:
Improveweld distortion correction accuracyVSAvoidcomplexity of welding control system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The measurement device measures the tilt of the fitting member with respect to the axial direction of the rod-like member, providing feedback information about the weld distortion. This measurement data guides the TIG welding correction process, enabling precise control of heating conditions to achieve accurate distortion correction.

Inventive Principle:
Principle #23Feedback

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

Enables precise measurement and correction of the tilt of the fitting member with respect to the rod-like member, reducing weld distortion and ensuring high-quality welds between the raw pipe and the fitting member through accurate shaping of weld beads.

Implementation Method 1

by placing the reference surface on the roller contact member, the rod-like member can rotate by following the reference surface

Methodology Applied
Scientific EffectRolling contact: Roller

Implementation Method 2

a weld distortion in the vicinity of the weld portion of the steel material is removed by heating the weld bead using a tungsten inert gas (TIG) welder under a predetermined heating condition

Methodology Applied
Scientific EffectThermal heating: Heating

Implementation Method 3

a tilt of the fitting member with respect to the rod-like member can be measured with high accuracy using the measurement device

Methodology Applied
Scientific EffectPosition detection:

Implementation Method 4

the fitting member welded to at least one longitudinal end of the rod-like member

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP3173181B1Warping correction method
Publication Date: 2018.12.26 MITSUBISHI HEAVY IND LTD
  • EP3173181B1 patent drawingFigure 1~2
  • EP3173181B1 patent drawingFigure 3~4

AI summary

A distortion correction method includes: a reference surface forming process S1 for fabricating a reference surface as a circumferential surface in an outer circumference of a raw pipe having both axial ends to which fitting members are welded; a connecting member installation process S3 for installing a reference surface of the raw pipe in a roller contact member that rotatably supports the raw pipe; a measurement process S5 for measuring a tilt of the fitting member rotating along with the raw pipe by virtue of the roller contact member with respect to an axial direction of the raw pipe using a dial gauge; and a distortion correction process S6 for performing TIG welding for a weld portion between the raw pipe and the fitting member on the basis of a result of the measurement in the measurement process S5 to correct the tilt of the fitting member with respect to the axial direction of the raw pipe.