Electric Resistance Welding Pipe Edge Tapering for Penetrator Discharge

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Solution Overview

Problem

Conventional electric resistance welding processes face challenges in achieving optimal weld toughness and strength due to the presence of oxides, known as penetrators, which are not effectively discharged during the welding process, leading to reduced manufacturing efficiency and poor weld characterization.

Innovation Solution

The proposed solution involves shaping the lateral edges of the strip with a two-stage or three-stage tapering configuration using cutting or shaving rolls, with specific angle and length adjustments to ensure effective discharge of melting steel and removal of penetrators, thereby enhancing weld quality without compromising manufacturing efficiency across varying strip thicknesses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional electric resistance welding is performed without edge shaping, then the welding process is simple and fast, but penetrators remain in the weld causing reduced toughness and strength

Engineering Contradiction:
Improveweld toughness and strengthVSAvoidedge shaping equipment
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by shaping the lateral edges of the strip with tapering (at angles of 10-45 degrees) before the welding process. This pre-shaping of the edges ensures that penetrators can be effectively discharged during welding, improving weld toughness and strength without requiring complex equipment modifications during the welding itself.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the geometric parameters of the strip edges by introducing specific tapering angles (10-45 degrees) and lengths (5-50mm). This parameter modification enables effective penetrator discharge during welding, resolving the contradiction between weld quality and equipment complexity by using simple geometric changes rather than complex welding process modifications.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If edge tapering is applied to improve penetrator discharge, then weld quality improves, but the manufacturing process becomes more complex and time-consuming

Engineering Contradiction:
Improveweld characterizationVSAvoidmanufacturing efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent optimizes the tapering parameters (angles of 10-45 degrees and lengths of 5-50mm) to achieve effective penetrator discharge within a reasonable processing time. These parameter ranges balance the need for adequate tapering to remove penetrators with the constraint of maintaining manufacturing efficiency, avoiding excessive processing time while ensuring weld quality.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by tapering only the lateral edges of the strip where penetrators form, rather than processing the entire strip. This localized edge shaping minimizes the additional manufacturing time and complexity while effectively addressing the penetrator discharge issue at the critical welding locations.

Inventive Principle:
Principle #3Local quality

3Object-generated harmful factors

If the lateral edges are shaped with adequate tapering, then melting steel discharges effectively removing penetrators, but the edge shaping process requires additional equipment and process steps

Engineering Contradiction:
Improvepenetrator removalVSAvoidcutting or shaving means
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies local quality by using cutting or shaving means that process only the lateral edges of the strip (5-50mm width) where penetrators form, rather than processing the entire strip. This localized approach effectively removes penetrators while minimizing the complexity and cost of the edge shaping equipment required.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses preliminary action by shaping the lateral edges with tapering before the welding process. This pre-shaping ensures that when welding occurs, the melting steel can effectively discharge and remove penetrators. The cutting or shaving means are positioned to process edges in advance of the welding operation, improving weld quality without requiring complex equipment during the welding itself.

Inventive Principle:
Principle #10Preliminary action

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 results in electric resistance welding pipes with improved weld toughness and strength, as demonstrated by higher Charpy impact values and lower brittle fracture surface ratios, ensuring reliable product performance.

Implementation Method 1

apparatus for inductively heating lateral edges of the roll-formed strip

Methodology Applied
Scientific EffectInductive heating: Induction Heating

Implementation Method 2

electric resistance welded pipe is formed by welding without using weld metal

Methodology Applied
Scientific EffectElectric resistance welding: Welding

Data Source

PatentEP2039441B1Apparatus for manufacturing seam-welded pipe excelling in welded portion characteristic
Publication Date: 2020.09.09 JFE STEEL CORP
  • EP2039441B1 patent drawingFigure 1~3B
  • EP2039441B1 patent drawingFigure 4A~5C
  • EP2039441B1 patent drawingFigure 6A~7

AI summary

Manufacturing equipment of electric resistance welding pipes is provided, in which lateral edges of a strip for an electric resistance welding pipe is shaped with appropriate tapering immediately before electric resistance welding so that welding quality is kept excellent. (1) Cutting or shaving means 3 is provided after a leveler 2. (2) At least one finpass forming stand 4 is provided, which includes a fin having tapering having at least 2 stages. The manufacturing equipment of electric resistance welding pipes satisfies at least one of the above (1) and (2).