Exciting developments in the welding world
Mr. Satish Bhat, Managing Director, Ador Welding Ltd.
Q. What’s exciting in the welding industry today?
The recent trend of welding technology development and applications include welding processes as well as special materials and alloys. The target is to achieve better joint strength, lighter parts, reduced metal fatigue, repetitive quality, higher productivity, green processes and safe working environments.
As an example of special alloy, the world’s first YP390F class steel for large heat input welding specifications has been developed by utilizing advanced micro alloying technology. Conventionally, multipass welding with a small heat input had been used with F class steels for low temperature specifications in order to guarantee the low temperature toughness of the welding heat affected zone (HAZ). The new technology has made it possible to develop a high strength, heavy thickness steel plate that displays excellent low temperature toughness and is also suitable for high efficiency 1-pass large heat input welding. Steel plates applying the developed technology have been adopted and applied practically in liquefied natural gas (LNG) ships with cold climate specifications.
Regarding the special welding processes, the advanced systems are:
Tandem MIG Welding, Robotic MIG and TIG Welding, Laser Welding, Laser Arc Hybrid Welding, Friction Stir Welding, Electron Beam Welding, Hot Wire TIG Welding Process and its applications in Orbital Welding, Orbital MIG / FCAW Welding, Narrow Gap SAW Welding, Narrow Gap MIG / MAG welding systems, Narrow gap hot wire TIG welding system, Advanced Cladding systems.The future trends in Welding can be envisaged to be – Unified Power Block Design for different capacity welding machined and Pay-on-Demand usage of Welding.
Q. We have been talking about automation for quite some time. What is the level of automation we could achieve so far?
In fact, to achieve the perfect qualities and higher levels of productivities, most manufacturing processes involving metal joining and cutting are moving towards Automation, partial or complete process lines. Complete Robotic Work cells (unmanned) with intelligent handling, vision control and anti-collision systems have been developed both for automobile as well as other heavier fabrication industries like shipbuilding, heavy structural fabrication etc.Narrow Gap MIG, TIG and SAW systems are invariably fully automated with multi-axis motion controls, seam tracking, intelligent arc control, and capable of rolling out a variety of parts with the touch of a fingertip to change the job program number. Wind Tower fabrication, ship building, pressure vessel fabrication, pipe lines – all are industries moving heavily towards these processes. Fully automated laser stitch and spot welders will come largely in application in the thin sheet fabrication in automobiles and aircrafts. Friction Stir Welding Automation is another exciting automated process which can weld a wide variety of thicknesses using the same outfit – 1.2 to 25 mm in one-sided welding and up to 50 mm in two- sided welding. This process does not require any filler material, as most environment friendly as it does not give out any welding fumes or toxic chemicals to the air.Hot Wire TIG Processes is now replacing MIG in many automated applications for vertical cladding (internal and external) anti-corrosion weld overlay cladding of manifolds for petrochemical and gas industries.
Q. Could you elaborate on the use of digital technology in welding and the benefits reaped so far?
In addition to enhanced performance characteristics, the ability for direct digital control has also markedly expanded the automation possibilities of difficult welding processes. This direct control allows these supplies to become an integral part of the complete system and all of their capabilities to be accessed and controlled from a single controller. With the ability to enable/disable the supplies, change modes between DC and AC, vary current, voltage, and AC phasing, all based on part or torch position, automated continuous root-to-cap multipass welds are achievable.
Waveform Control Technology® is adapted for Root Pass MIG and submerged arc welding. The power supplies provide constant current or constant voltage operation and allow variable frequency and amplitude for AC output. The software-driven AC, DC-positive or DC negative output allows the user to control the deposition and penetration. The result is a more consistent, smoother arc at a wider range of parameters, increased weld speeds, consistently higher-quality welds, and improved efficiencies in a single- or multi-arc environment.
The sophistication of the software based inverter design allows a significant ability to be integrated into an adaptively controlled dynamic system required for the challenging narrow groove environment. Newer, more advanced power sources and seamless integration into the overall narrow groove system architecture have dramatically enhanced the operating envelope and flexibility of the welding process. It is important to note that the efficiency of these inverter-based power supplies yields significant savings in operating costs over traditional transformer/rectifier designs. In a typical industrial operating environment fabricating pressure vessels, each machine can potentially save up to 7,00,000 per year in operating costs due to its unique design and use of energy- efficient, high-speed inverters.
