Swing-Arc Narrow-Gap Submerged Arc-Welding Process Assisted by Pre-Embedding Cold Wires

Area of Science:

• Materials Science and Engineering
• Welding Technology

Background:

• Conventional narrow-gap submerged arc welding (NG-SAW) faces challenges including poor weld formation, difficult slag removal, and suboptimal joint microstructure and hardness.
• Understanding the slag adhesion mechanism is crucial for improving weld quality.

Purpose of the Study:

• To introduce and evaluate a novel swing arc NG-SAW process assisted by pre-embedded cold wires.
• To address the limitations of conventional NG-SAW, focusing on weld formation, slag detachability, microstructure, and hardness.

Main Methods:

• Implementation of a swing arc NG-SAW process with optimized welding energy parameters and the addition of cold wires.
• Analysis of slag adhesion mechanisms, including elemental diffusion at the weld-slag interface.
• Microstructure evolution analysis of multilayer welded joints, considering variable-angle groove design and the heat-absorbing effect of cold wires.

Main Results:

• The new process ensures sound weld formation and enhanced slag detachability.
• Welding efficiency was improved by reducing weld layers by 33.3%.
• Grain refinement in the weld metal and reheat-affected zones was achieved, along with a 54% enhancement in hardness uniformity within the HAZ.

Conclusions:

• The swing arc NG-SAW process with cold wires effectively overcomes the limitations of conventional methods.
• The optimized process leads to superior weld quality, improved microstructure, and enhanced mechanical properties.
• This innovative approach offers a significant advancement in multilayer welding efficiency and joint integrity.