Knowledge Is Power: Why Training Matters More Than Ever in Orbital Welding

Understanding Gases in the Orbital Welding Process

Shielding Gases

When evaluating orbital welding training programs, it’s important to consider how much instruction is devoted to shielding gases and the critical role of purging. Trainees must understand how shielding gases protect the electrode and molten weld pool from atmospheric contamination. In Gas Tungsten Arc Welding (GTAW), the most commonly used shielding gases are argon, helium, and mixtures of the two—typically reserved for specialized applications.

Welders must be familiar with the proper helium-to-argon ratios. The effectiveness of a shielding gas is largely determined by its density. Argon, which is approximately 1.33 times denser than air, effectively blankets the weld area and displaces atmospheric gases. Helium, on the other hand, is less dense and tends to rise, making it less effective unless used at two to three times the flow rate of argon to achieve comparable coverage.

Shielding gases also influence the metallurgical properties of materials. Argon generally provides a quieter, more stable arc and is preferred due to its lower cost and reduced flow rate requirements. Understanding how to select the appropriate shielding gas is a critical skill for any orbital welder.

Gas Purging

The success of an orbital weld is heavily dependent on proper gas purging techniques—also known as backing gas application. Surprisingly, many experienced welders underestimate its importance. In fact, gas purging is often considered the “Achilles’ heel” of orbital welding. As such, training programs must thoroughly cover purging principles, including how to calculate appropriate purge times.

The first step in effective purging is selecting the right gas—usually argon. Argon is available in varying levels of purity, and selecting the correct grade for the application is essential. Defining and maintaining the correct flow rate and pressure through the tubing or piping and across the weld joint is critical. This procedural step is often the source of errors if not properly executed.

Incorrect or omitted purging can compromise an entire system. Internal pressure helps keep the weld bead flush with the inner wall of the components, while the correct gas flow ensures the weld metal and heat-affected zone remain clean and free from oxidation.

Selecting Quality Materials for Welds

Even the most advanced orbital welding system cannot compensate for poor-quality materials. The foundation of a quality weld begins with the base material. Proper training must address topics such as composition and metallurgy—particularly how elements like sulfur affect weld quality.

Orbital welding programs should cover how to inspect incoming materials and verify material certifications. Trainees should also learn how to evaluate supporting documentation to ensure compatibility and quality compliance.

Mild Steels

In mild steels, orbital weld quality is significantly influenced by impurities in the base metal, including sulfur, phosphorus, and oxygen. Additionally, these materials are susceptible to hydrogen embrittlement if exposed to hydrocarbons or moisture contamination.

Nickel Alloys

Nickel alloys are prized for their corrosion resistance and are frequently used in aggressive environments. However, they present welding challenges, including a higher tendency for cracking, making training in proper techniques essential.

Refractory and Reactive Metals

Orbital welding is the preferred method for joining tubing and pipe made from refractory metals (e.g., molybdenum, tantalum) and reactive metals (e.g., titanium, zirconium). These metals oxidize rapidly at high temperatures and must be shielded by inert gases. Orbital GTAW offers the best control over heat input and inert gas coverage among arc welding processes, making it ideal for these materials.

Stainless Steels

Stainless steels are corrosion-resistant due to their minimum 10.5% chromium content, which allows them to form a self-healing oxide layer. These steels are categorized by microstructure—austenitic, ferritic, or duplex (a balanced mix of both). While generally weldable, each microstructure presents different challenges that must be considered during welding.

Sulfur Content Considerations

Sulfur, often added to improve machinability, significantly affects welding behavior. In welding, varying sulfur levels alter the surface tension of molten metal, influencing heat flow and penetration. A mismatch in sulfur content between components can cause bead shift, where the weld pool gravitates toward the material with lower sulfur content—potentially leading to misalignment or incomplete joint fusion.

Understanding sulfur differentials is crucial. Orbital welding trainees must learn how to evaluate and match components based on sulfur levels to avoid weld defects.

Empowering Welders Through Knowledge: The Critical Role of Training in Orbital Welding

As the global demand for skilled welders continues to outpace supply, orbital welding has emerged as a powerful solution—boosting productivity while requiring fewer personnel. However, it's a misconception that automation reduces the need for skilled labor. In fact, the opposite is true.

At our training school, we emphasize that automation demands a higher level of expertise, not less. To operate orbital welding systems effectively, technicians must have a strong foundation in areas such as machine programming, metallurgical principles, gas flow control, system calibration, and quality assurance.

We provide comprehensive, hands-on training led by certified instructors, ensuring our graduates are equipped with the up-to-date knowledge and practical skills needed to meet modern industry standards. Because in orbital welding, as in all technical fields, knowledge truly is power.