Submerged Arc Welding Current Switching for Deep Penetration

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Solution Overview

Problem

Existing submerged arc welding methods often result in incomplete penetration, especially in single pass welding or the first layer of multi-layer welding, due to limitations in adjusting output current and voltage, which can lead to issues like lack of penetration bead and fusion width, and these methods are not effective for DC welding.

Innovation Solution

A submerged arc welding method that periodically switches between low and high average welding currents to achieve deeper penetration, using a control device to manage the switching frequency and current fluctuation, allowing for deeper penetration bead formation without altering the output current and voltage ranges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional submerged arc welding methods are used with fixed output current and voltage, then welding process stability is maintained, but penetration depth is insufficient

Engineering Contradiction:
Improvepenetration depthVSAvoidwelding condition control
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies periodic action by switching welding conditions between first and second states at regular intervals. The control device periodically changes the output current and voltage according to a set cycle, creating alternating high and low heat input phases that progressively deepen penetration while maintaining overall process stability.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent implements dynamics by transitioning from fixed welding parameters to dynamically changing conditions. The control device continuously adjusts output current and voltage based on the switching cycle, allowing the welding process to adapt between different thermal states to achieve deeper penetration without sacrificing stability.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If output current and voltage are increased to achieve deeper penetration, then penetration depth improves, but welding process stability deteriorates

Engineering Contradiction:
Improvepenetration depthVSAvoidwelding process stability
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

By periodically alternating between first welding conditions (higher current/voltage for deep penetration) and second welding conditions (lower current/voltage for stability), the system achieves deep penetration without sustained high energy input that would destabilize the process. The regular switching cycle prevents thermal accumulation issues while maintaining penetration depth.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent changes welding parameters (current and voltage) between two distinct states rather than maintaining a single high-value setting. This parameter switching allows the system to achieve deep penetration during the first condition while the second condition provides thermal management and process stability, resolving the contradiction between penetration depth and stability.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If AC submerged arc welding with regulated positive and negative periods is used, then penetration can be adjusted, but the method is not effective for DC welding and has limited adaptability

Engineering Contradiction:
Improvepenetration controlVSAvoidwelding type compatibility
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The control device is designed to universally apply to both AC and DC welding types. The switching mechanism between first and second welding conditions is implemented through a unified control system that can operate with either alternating current or direct current, making the deep penetration method adaptable to different welding applications without requiring separate systems.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The periodic switching of welding conditions creates a universal approach that works for both AC and DC welding. For AC welding, the switching can be synchronized with the AC cycle; for DC welding, the switching creates an artificial periodic pattern. This makes the penetration control method universally applicable across different current types.

Inventive Principle:
Principle #19Periodic 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 method achieves deeper penetration and stable deep penetration bead formation, particularly in penetration bead welding using a backing material, by applying high heat input during high current periods, thereby improving welding quality without destabilizing the welding process.

Implementation Method 1

a welding wire W and a base material A

Methodology Applied
Scientific EffectElectric arc: Electric Arc

Implementation Method 2

first average welding current is supplied to a welding wire; and setting a second welding condition under which second average welding current is supplied to a welding wire

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP4410466A1Submerged arc welding method and submerged arc welding machine
Publication Date: 2024.08.07 DAIHEN CORP
  • EP4410466A1 patent drawingFigure 1
  • EP4410466A1 patent drawingFigure 2
  • EP4410466A1 patent drawingFigure 3A~3B

AI summary

The present application relates to a submerged arc welding method and to a corresponding submerged arc welding machine. The method comprises setting a first welding condition under which first average welding current is supplied to a welding wire ; and setting a second welding condition under which second average welding current is supplied to a welding wire, and the first welding condition and the second welding condition are periodically switched.