A hybrid laser welder combines laser with gas metal arc welding to make a sandwich panel from thin metal sheet.

Advances in two technologies – hybrid laser welding and friction stir welding metals – were recently introduced, and they have the potential to change the way welded products are designed and made.

These processes are designed to be faster and less expensive than other welding processes, and they have been engineered to require fewer skills for the welders who use them, so they are user-friendly to the point that highly skilled welders would not be needed.

ESAB Welding & Cutting Products (www.esab.com) demonstrated the two processes at a press conference on April 23 in Florence, S.C., and ESAB executives said the developments that their company has made with these two processes have advanced the technologies they represent to new levels.

In speaking about the new developments, Jeff Hoffart, senior vice president and general manager for equipment, cutting and steel industry products for ESAB, compared them to previous advances in welding.

Friction stir welding An established process for welding low melting temperature materials such as aluminum, brass and copper, ESAB said it has extended friction stir welding to metals with higher melting temperature such as ferritic steels, stainless and duplex stainless steels, and nickel base alloys. This is possible through the use of tools made from polycrystalline cubic boron nitride (PCBN), polycrystalline diamond (PCD), and abrasive materials such as metal matrix composites (MMC). Friction stir welding has a welding head that spins a tool and presses the tool against the materials that are being welded. The combination of spinning and high pressure creates friction that puts the metal into a plastic state, joining the two pieces and making the weld. The process creates a very high quality weld because melting does not occur, so the basic metallurgical qualities of the welded metals are not changed, and joining takes place below the melting temperature of the material.The process has low heat input, with minimal distortion, and does not require filler material. It also does not produce fumes.

“We went from stick welding to MIG welding, from MIG to TIG welding, from single-wire subarc welding to dual-wire subarc welding, and now we have four and five-wire subarc welding.

“All of those were baby steps that allowed a fabricator to increase his speed 5, 10 or 20 percent and as much as 50 to 100 percent on their best days,” Hoffart said.

“Now, we are talking about processes that will increase welding speeds by a factor of four, five or six times. This is disruptive technology,” Hoffart added.

The processes that he spoke about are hybrid laser arc welding (HLAW) and a new friction stir welding system that is designed to weld high melting temperature materials, including ferrous alloys.

Hybrid laser arc welding combines the deep weld penetration and low heat input associated with laser welding with the power efficiency and gap tolerance of gas metal arc welding.

ESAB executives said their company’s new HLx Series of welding equipment is the first commercially available mechanized laser-welding systems that can be programmed to use laser-only welding, laser welding with cold wire fill, or hybrid laser arc welding in a 2D gantry, 3D robotic or custom mechanized solution with closed-loop weld process control. In addition, ESAB executives said their company is the first to offer all of the components of these systems as single-sourced units that will be supported and serviced by a single company.

Hoffart said the combination of welding technologies represented in the hybrid laser system represents a new alternative for welding.

The system provides deep penetration and fast weld speeds of laser welding with reduced heat infusion into the part and reduced distortion that causes plates to buckle and warp.

The addition of gas-metal arc welding to the laser process creates a wider weld bead that is capable of bridging much larger weld gaps. The deep penetration that laser welding can achieve also can limit the ability of laser welding to produce acceptable weld fusion in weldments that have gaps between parts.

By putting gas metal arc welding, with a small amount of filler metal, in tandem with the laser, the system can produce quality welds that are as much as four times as wide as conventional laser processes can handle.

Adding gas metal arc welding to the welding mix also enhances a finished part’s metallurgical stability, and with gas metal arc welding’s slower cooling rates, produces welds with greater strength and less brittleness.

ESAB engineers said the combination of welding processes is especially beneficial for high alloy steels that are sensitive to hot cracking.

“We can get higher weld quality with harder, more exotic materials, materials that are difficult to weld with conventional welding techniques,” Hoffart said.

ESAB has used its hybrid laser system to weld -in.-thick plates of tool steel in one pass, a job that would require five to seven passes with conventional welding processes, Hoffart said.

The hybrid laser welding system was made commercially available less than six months ago.

Hoffart said the process can be used to weld very thin metal sheets to produce a sandwich structure that is comparable to the structure of cardboard. Those sandwiched sheets have the potential to be used in a wide number of applications, from bridge decks to superstructures on ships, he said.

The process has been used in shipbuilding in Europe, and the U.S. Navy Joining Center, in a project funded by the Office of Naval Research and the National Shipbuilding Research Program, examined the process more than six years ago as part of their Shipbuilding Initiative for the fabrication of ship structural components.

Separately, ESAB unveiled its new friction stir welding that is based on technology developed by MegaStir. MegaStir is a strategic alliance between SII MegaDiamond Inc., a business unit of Smith International Inc., and Advanced Metal Products Inc.

In February, MegaStir gave ESAB an exclusive license to manufacture and distribute friction stir welding machines for ferrous alloys, non-ferrous alloys, metal matrix composites and superalloys. The license is for worldwide distribution rights, but certain countries are excluded.

Hybrid laser welding A process that combines laser and gas metal arc welding to produce high quality welds in hardened steels, high-alloy steels and other hard, exotic metal alloys. As engineered by ESAB, the systems include a patented closed-loop control to monitor the weld joint in real time and to modify the process to accommodate joint mismatches. The control is designed to monitor and adapt the welding process faster than a human operator could to allow travel speeds that would not be possible with conventional control systems. This technology is available as a robotic system, a portable tractor system or on a moving gantry. The hybrid process improves process efficiency and overall productivity, improves weld quality, lowers production costs and offers more versatility than conventional welding processes. ESAB said it sets new standards for productivity, cost efficiency and flexibility in heavy fabrication applications.

Friction stir welding previously was limited to low melting temperature materials such as aluminum, brass and copper.

ESAB’s new system expands friction stir welding to metals with higher melting temperatures such as ferritic steels, stainless and duplex stainless steels, and nickel base alloys by use of tools that are made from polycrystalline cubic boron nitride (PCBN), polycrystalline diamond (PCD), and abrasive materials such as metal matrix composites (MMC).

Friction stir welding is a solidstate joining process that provides lower total heat input and the elimination of solidification defects associated with arc welding. In the process, the tool on the welding head spins as it is pressed against the materials that are being welded. The combination of spinning and pressure create friction that puts the metal into a plastic state, joining the two pieces and making the weld.

Company executives said the process creates a very high quality weld because melting does not occur and joining takes place below the melting temperature of the material. So the process has low heat input, with minimal distortion, and does not require filler material. It also does not require special surface preparation, and it does not produce welding fumes.

“Friction stir welding also is highly efficient and more environmentally friendly than other welding methods and permits joining of dissimilar metals,” Hoffart said.

ESAB demonstrated its friction stir welding with a pipe welding unit that is designed with a special spindle head and pipe clamp that holds the pipe in place.

The tool on a friction stir welding machine glows red as it welds two pipe segments. Friction from the spinning tool makes the weld material plastic and completes the weld.

The system includes an anvil that is placed inside the pipe. The friction stir welding head revolves around the exterior to create the weld. The system is equipped with a proprietary take-off tool that ensures a solid weld is achieved through the finish of the process. It can be used to produce new pipelines and to repair existing pipelines.

“This is a done-in-one process,” Jeff Defalco, ESAB’s business manager for welding automation said.

The system is designed to weld a -in. pipe in one pass and reduces costs because it does not require filler metal, flux or shielding gases, Defalco said.

ESAB has sold friction stir welding products for aluminum and other non-ferrous metals since 1992.