Multi-Electrode Submerged Arc Welding for Stable High-Current Arcs

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Solution Overview

Problem

Multi-electrode submerged arc welding using five or six electrodes faces challenges with magnetic interference, leading to unstable arcs and welding defects such as bead irregularity and insufficient penetration, particularly in large-current applications for thick steel plates and large-diameter steel pipes.

Innovation Solution

The method involves adjusting the disposition of electrodes and welding currents, with specific current densities and distances between electrodes to suppress magnetic interference, ensuring stable arcs and deep penetration by using five or six electrodes in a controlled manner, with alternating current supplied to some electrodes and direct current in reverse polarity to the first electrode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the number of electrodes is increased to increase welding speed, then productivity is improved, but magnetic interference becomes more complex causing arc instability and welding defects

Engineering Contradiction:
Improvewelding speedVSAvoidarc stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies periodic action by alternating the polarity of welding currents between adjacent electrodes. Specifically, odd-numbered electrodes receive direct current while even-numbered electrodes receive alternating current, creating a periodic pattern that systematically manages magnetic field interference. This periodic alternation prevents continuous magnetic accumulation and stabilizes arcs across all electrodes simultaneously, enabling reliable operation with 5-6 electrodes at high welding speeds.

Inventive Principle:
Principle #19Periodic action

2Manufacturing precision

If welding current is increased to increase deposit metal amount, then manufacturing precision is improved, but magnetic interference increases causing bead irregularity

Engineering Contradiction:
Improvepenetration depthVSAvoidmagnetic interference
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by assigning different current characteristics to different electrodes based on their positions. Odd-numbered electrodes (1st, 3rd, 5th) receive direct current with higher current density for deep penetration, while even-numbered electrodes (2nd, 4th, 6th) receive alternating current with lower current density to reduce magnetic interference. This localized differentiation allows each electrode to contribute optimally to penetration while minimizing overall magnetic interference, maintaining bead regularity even at high total currents exceeding 1000A.

Inventive Principle:
Principle #3Local quality

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 enables deep penetration, a large amount of deposit metal, and stable arcs, preventing welding defects while increasing welding speed, resulting in high-quality beads and efficient industrial processes.

Implementation Method 1

welding currents supplied to respective welding wires of a large number of electrodes generate magnetic fields

Methodology Applied
Scientific EffectMagnetic field generation: Electromagnetic Induction

Implementation Method 2

submerged arc welding is commonly performed in which welding is performed with two or more electrodes disposed in line

Methodology Applied
Scientific EffectElectric arc heating: Electric Arc

Data Source

PatentEP3417979B1Multi-electrode submerged arc welding method
Publication Date: 2024.07.03 JFE STEEL CORP
  • EP3417979B1 patent drawingFigure 1(a)~1(b)
  • EP3417979B1 patent drawingFigure 2
  • EP3417979B1 patent drawing

AI summary

Provided is a multi-electrode submerged arc welding method that enables, in multi-electrode submerged arc welding using five or six electrodes, a deep penetration and a large amount of deposit metal to be obtained by supplying a large current, and enables stable arc to be generated by respective electrodes by suppressing magnetic interference. In addition, welding defects can be prevented, and beads with a good shape or appearance can be obtained. Furthermore, the welding speed can be increased. In the multi-electrode submerged arc welding method for butt welding of a thick steel plate with a thickness of 15 to 45 mm by using multiple electrodes, a distance between electrodes, current densities of welding currents and angles of electrodes are appropriately set.