Submerged Arc Welding Control for Stable Arc Length Convergence

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Solution Overview

Problem

Conventional submerged arc welding methods face challenges in maintaining stable arc length control due to sensitive feed speed fluctuations and errors in welding voltage, leading to unstable welding states and improper setting and control of welding conditions.

Innovation Solution

A submerged arc welding control method and system that utilize a combination of external characteristics and variable speed control to ensure the welding current and voltage converge at a set intersection point, with a negative slope, allowing for precise control of arc length and stable welding conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a large gain is set to sharply increase or decrease the feed speed, then the arc length can quickly approach the desired value, but the feed speed fluctuates too sensitively causing an unstable welding state

Engineering Contradiction:
Improvefeed speed response speedVSAvoidwelding state stability
Core Design Contradiction:
SpeedVSStability of the object's composition

Solution Approach 1:

The patent implements feedback control by detecting the welding voltage and comparing it with the set value, then adjusting the feed speed based on the error signal. This closed-loop feedback mechanism enables the system to automatically correct arc length deviations while maintaining stable welding conditions through proportional control with appropriately tuned gain parameters.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If conventional variable speed control is used, then the welding voltage can be maintained at an appropriate value, but the welding voltage will have an error from the voltage set value causing issues in the setting and control of welding conditions

Engineering Contradiction:
Improvevoltage control accuracyVSAvoidwelding condition control precision
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent changes the control parameter from feed speed alone to a combination of current and voltage control. By setting external characteristics with a negative slope and controlling both current and voltage to converge at an intersection point, the system achieves precise control of welding conditions without the voltage errors that plague conventional feed-speed-only control methods.

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

The method and system achieve stable arc length control with reduced steady-state deviation and faster transient response, ensuring the welding current and voltage match set values, thereby improving the setting and control of welding conditions.

Implementation Method 1

a welding wire is fed into the flux to generate an arc between the tip of the welding wire and the base metal for welding

Methodology Applied
Scientific EffectElectric arc: Electric Arc

Data Source

PatentEP4670892A1Submerged arc welding control method and submerged arc welding system
Publication Date: 2025.12.31 DAIHEN CORP
  • EP4670892A1 patent drawingFigure 1
  • EP4670892A1 patent drawingFigure 2(A)~2(C)
  • EP4670892A1 patent drawingFigure 3(A)~3(C)

AI summary

A submerged arc welding control method is provided for performing welding by feeding a welding wire and outputting a welding current and a welding voltage in accordance with set external characteristics. The method includes: setting a current set value and a voltage set value; setting the external characteristics so as to pass through an intersection point of the current set value and the voltage set value and have a negative slope at the intersection point; performing variable speed control of feed speed of the welding wire such that the welding voltage is equal to the voltage set value; and causing an operating point of the welding current and the welding voltage to converge at the intersection point of the external characteristics.