High-Penetration STIG Keyhole Welding System (SWS-1000)

The High-Penetration STIG Keyhole Welding System (SWS-1000) represents a new generation of arc welding technology. By applying highly efficient electromagnetic arc constriction, the system achieves plasma-like arc characteristics while maintaining the simplicity of TIG welding. This innovative process delivers concentrated arc energy and a stable keyhole effect, enabling deep penetration, high welding speed, and exceptional weld quality.

Positioned between conventional TIG welding and plasma arc welding, STIG welding offers a powerful solution for medium and thick plate applications where productivity, weld integrity, and cost efficiency are critical.

At FNS Pipeline Technology Co., Ltd., the SWS-1000 STIG welding system is engineered to meet the stringent demands of modern pipeline fabrication, pressure equipment manufacturing, and high-end industrial welding.

SWS-1000 high penetration STIG keyhole welding system by FNS Pipeline Technology Co., Ltd

STIG Welding Principle: Stable Keyhole, Deep Penetration

During STIG welding, the electromagnetically compressed arc generates high energy density. A dynamic balance is formed between arc pressure and the surface tension of the molten metal, creating a stable keyhole effect. This allows the arc to penetrate deeply into the workpiece, achieving full penetration in a single pass without groove preparation.

The system is capable of one-pass full penetration welding of steel plates up to 12 mm thick, and even thicker materials such as titanium alloys can be welded under optimized conditions.

System Configuration of SWS-1000

The SWS-1000 adopts an integrated all-in-one design, ensuring compact structure, reliable operation, and easy maintenance. The system includes:

• Welding power source with built-in arc voltage tracking
• Integrated cooling water unit
• STIG welding torch
• Precision wire feeder (optional)

All major components—including the power supply, cooling system, arc voltage control, and central control unit—are fully integrated into a single platform, significantly reducing failure points and simplifying operation.

Key Features of STIG Welding Technology

STIG arc welding is a high-speed, full-penetration welding process capable of welding metal materials up to 16 mm thick (such as titanium alloys) without edge preparation.

Key technical characteristics include:

• Single-sided welding with double-sided forming
• Welding speed 5–10 times faster than conventional TIG welding
• Smooth, ripple-free molten pool and excellent bead appearance
• Front weld width approximately 1.5 times plate thickness
• Back bead width only 2–3 mm
• 100% parent metal fusion with no multiple fusion lines
• Complete elimination of common defects such as slag inclusion and porosity

Thanks to the high-quality molten pool control, no back gouging, surface polishing, or post-weld grinding is required, significantly reducing production time.

Advantages of the SWS-1000 STIG Welding System

1. High Speed, High Quality, High Efficiency

The SWS-1000 uses a high-energy-density electromagnetically compressed arc to form a stable keyhole, enabling deep penetration and excellent weld consistency. For example, when welding 10 mm stainless steel, welding speeds can reach up to 300 mm/min, more than 8 times faster than conventional TIG welding.

Radiographic inspection pass rates exceed 95%, with clean, defect-free welds free from porosity and slag inclusions. Compared with traditional TIG, GMAW, and SAW, the STIG process demonstrates clear advantages in speed and quality.

2. Reduced Labor, Lower Costs

The STIG welding process eliminates the need for groove preparation for medium-thickness materials, reducing machining, filler material usage, and labor input. Single-pass full penetration minimizes rework caused by welding defects, while narrow back beads eliminate back gouging operations.

In medium-thickness carbon steel and thick-plate root pass welding, the SWS-1000 delivers unmatched advantages in quality, efficiency, and overall welding cost, outperforming conventional submerged arc welding and GMAW processes.

Automation and Intelligent Connectivity

The SWS-1000 is equipped with an advanced arc voltage tracking system, automatically compensating for height variations along the weld seam. This ensures a constant distance between the tungsten electrode and the workpiece, improving gap tolerance and weld consistency.

With built-in communication interfaces, the system can be seamlessly integrated with robotic systems and automated production lines. Welding parameters—such as current ramp-up/down and shielding gas timing—can be remotely controlled to support fully automated and dynamic welding processes.

Typical Applications

The SWS-1000 High-Penetration STIG Welding System is widely used in industries requiring high weld integrity and productivity, including:

• Oil and petrochemical industry
• Food and pharmaceutical processing equipment
• Aerospace manufacturing
• Power generation, including nuclear power
• Water treatment systems
• Shipbuilding
• Boilers and pressure vessels (pipelines, heat exchangers, storage tanks, reactors)
• Large-scale infrastructure pipeline prefabrication and plate assembly

FNS STIG Welding Solutions

With strong expertise in advanced welding equipment and automated welding systems, FNS Pipeline Technology Co., Ltd. provides reliable STIG welding solutions tailored for high-efficiency pipeline fabrication and industrial manufacturing.

The SWS-1000 system enables customers to achieve faster production cycles, higher weld quality, and lower overall manufacturing costs—supporting the next generation of intelligent welding applications.