Dual TIG Active Arc Additive Manufacturing Method and Process

Literature Overview

This 2024 publication from Chongqing University of Technology and Lanzhou University of Technology, published in the Welding Journal (焊接学报), introduces a novel dual-TIG active arc additive manufacturing (AM) method. The research is supported by the National Natural Science Foundation of China (Grant No. 51705054), the Chongqing Municipal Education Commission Science and Technology Research Project (KJQN202101135), and a graduate innovation project from Chongqing University of Technology (clgycx20203014). The work represents a significant advancement in wire-based arc additive manufacturing, particularly for depositing functional layers and building complex geometries with controlled microstructures.

Core Technical Approach

The dual-TIG configuration employs two independently controlled tungsten inert gas welding torches operating in synergy to create a combined heat input profile that differs fundamentally from conventional single-TIG processes. The "active arc" designation indicates that the arc parameters are dynamically modulated during deposition, likely through feedback-controlled adjustments to current, voltage, or torch positioning.

The dual-arc arrangement provides several advantages over single-arc systems: wider and more uniform heat input distribution, reduced cooling rate in the deposited layer, enhanced fluidity of the molten pool, and the ability to independently control the leading and trailing heat sources for asymmetric solidification.

Process Analysis and Engineering Implications

The key innovation lies in the "active" modulation of arc parameters. Unlike conventional TIG-based AM where parameters remain constant or follow simple programmed sequences, the active arc system likely incorporates real-time feedback from temperature sensors, optical monitoring, or acoustic signals to adjust arc energy delivery. This is particularly valuable for cladding applications where maintaining consistent dilution ratios between the deposited material and the substrate is critical for achieving the desired corrosion resistance or wear performance.

From a metallurgical perspective, the dual-arc approach offers several benefits for overlay cladding:

• Reduced thermal gradients between adjacent passes, minimizing residual stress accumulation
• Enhanced microstructural homogeneity through controlled solidification rates
• Improved bonding quality at the overlay-substrate interface due to optimized interfacial temperature
• Greater flexibility in selecting filler metals with different melting points

For pressure vessel fabrication involving weld-overlay cladding, this technology could enable thicker overlay layers with fewer passes, reducing production time while maintaining the mechanical integrity required by standards such as GB/T 150 and ASME VIII Div.1. The ability to precisely control dilution is especially important when cladding nickel-based alloys (such as Inconel 625 or Hastelloy C276) onto carbon steel substrates, where dilution exceeding 20–30% can compromise the corrosion resistance of the overlay layer.

Study Insights and Reflections

This research bridges the gap between traditional TIG overlay welding and modern additive manufacturing, retaining the cost-effectiveness and scalability of arc-based processes while incorporating the precision and adaptability of AM systems. The dual-arc configuration is particularly promising for large-scale industrial applications where deposition rates of 1–3 kg/h are required. Future work should focus on validating the technology for specific cladding applications, such as hydrogen service vessels requiring nickel-based overlay layers, and establishing qualification procedures under NB/T 47014 or ASME IX.