26 Oct Orbital Welding vs. Traditional GTAW
GTAW Process and Application
For the purpose of this discussion we will focus on the Gas Tungsten Arc Welding (GTAW) process, particularly as it relates to Orbital Welding process capabilities, including TIG (Tungsten Inert Gas) and MIG (Metal Inert Gas) or “Wire Feed” welding. And, we will keep our discussion around the welding of pipe and tube and the various process systems that utilize tubular materials.
These processes are most commonly used to weld thin sections of stainless steel and non-ferrous metals such as aluminum, magnesium, and copper alloys. The processes offer the operator greater control over the weld and allow for strong, higher quality welds. However, these processes are more complex and difficult to master, and furthermore, it is significantly slower than most other welding techniques.
GTAW processes have been utilized for many years for applications where high quality welds that require great integrity are needed. If done correctly, the integrity of these weld techniques are dramatic as TIG and MIG produce repeatable, leak tight welds with a very low level of contamination or byproducts. Many welding processes produce slag, great amounts of smoke, or simply throw weld debris in all directions during the weld process. GTAW remains one of the most controlled, clean welding technologies available for everyday use.
Increasing Importance of Safety and Cleanliness Requirements
Today more than ever, process systems carry fluids, gases and chemicals that must maintain a high degree of cleanliness or purity to fulfill their ultimate use. They also carry, hazardous, corrosive or flammable materials that that require critically important leak and exposure protection to other process systems and the people who handle them. With increasing measure and intensity, industries such as, Bio-Pharmaceutical, Semiconductor, Food & Dairy, Petroleum, Pulp and Paper, Chemical Processing, Medical Gas and many others are incorporating these requirements.
Conventional GTAW: Equipment & Skill Requirement
Conventional GTAW process equipment is fairly inexpensive, readily available and portable. With adequate training, welding can be performed sufficiently in a fabrication or field construction environment, resulting in high quality, high performance welding. The greatest challenge is operator quality. The dexterity needed to weld tubular materials, pipe or tubing, is difficult as the operator must maneuver around the material in a very consistent manner while maintaining complete gas coverage and full penetration to avoid leaks and contamination. This skill is developed over years of practice, and is truly a ‘knack’ that is possessed by very few weld technicians.
The Orbital Welding Process (in a nutshell)
Orbital Welding was developed to address the issue of operator error in GTAW processes. The process was developed 50 years ago, but is becoming increasingly popular in recent years. With automated welding, the computer-controlled process runs with little intervention from the operator. Computer controlled systems combine arc current, feed and speed to allow the ‘orbital weld head’ to travel around the tube in a steady and repeatable manner. The operator’s responsibility becomes simply fit-up and monitoring in most cases. Once a weld schedule (program) has been developed for a specific ‘heat’ of material, the weld profile should remain consistent.
High quality, repeatable welds can be delivered for critical applications but this comes with a price. The cost of Orbital Welding Equipment when compared with conventional equipment is 5-10 times the initial capital cost. The good news is that much of this cost can be recovered over time as productivity ranges between 2-3 times that of conventional means.
Questions to determine if you should move from Conventional to Orbital Welding:
- No matter the cost, does the customer or application require high integrity, repeatable welds?
- Will the payback on the capital cost be realized in less than three years? This is a difficult one as payback may be determined in several manners including, increased productivity, value added charges to the customer and most importantly, equipment utilization.
- Do we have staff that can transition from Conventional to Orbital processes with proper training and support?
- Will Orbital Welding capability separate our business from that of our competitors making us more likely to achieve additional business?
All the determining information adds up to the fact that the process of welding tubular materials will never be made easy. Giving time and effort to focus on the best approach for your project and the people you employ to get the job done is the difficult part of your decision process. For many mission critical applications, the trend is that Orbital Welding is increasing, with many companies leasing or renting orbital equipment on initial jobs. Embracing these technologies today will likely produce additional unforeseen opportunities for your company in the future.