By Clare Goldsberry, Associate Editor

Filler metals are available in a variety of types and materials designed specific applications. It's critical in welding to understand the application and the metals involved in it to select the right filler metal.

The AWS (www.aws.org) has numerous specifications that list the correct filler metals that should be used in welding and brazing to match the base metal and materials.

The leading producers of filler metals also provide detailed specifications for their products, and maintain up-to-date information on the applications on their Internet sites for common and specialty applications. Producers of specialty materials also provide information on welding their products.

For example, the Brush Wellman Co. (www.brushwellman.com) provides technical information on welding copper beryllium alloys. Those special alloys are one of that company's primary products, and the technical information it makes available improves their marketability.

Brush Wellman produces a copper beryllium stick electrode –tradenamed WeldPak – in three common sizes. Both the high strength and high conductivity copper beryllium use the same WeldPak filler.

Alternatively, an aluminum bronze filler (ERCuA1-A2) can be used to weld copper beryllium to steel.

For flux cored arc welding (FCAW), especially on critical structural steel applications, welding operators must choose their filler metals carefully. There is no "one-size-fits-all" solution for filler metals, and a wide range of variables will affect the operator's decision to use a particular wire. These factors include: thickness of the material, proper shielding gas, wire feed speed and voltage settings, location of the work site and weld appearance.

For example, Hobart Brothers (www.hobartbrothers.com) introduced a new generation of T-8 wire, the Hobart Fabshield XLR-8 that is designed to be used in out-of-position welding at high and low heat inputs. It is a self-shielded, flux-cored wire for structural applications, and the company says it is well suited for vertical-up welds at high current levels. It differs from gas shielded flux cored wires in that it does not require a separate shielding gas, making it more portable for outdoor use. The company said the XLR-8 is produced with lower diffusible hydrogen levels than competitive T-8 wires, and meets the new D-Designation under the AWS A-5.20.2005 standard, making it useable for AWS D1.8 Demand Critical Welds.

The company said its new generation of T-8 wire provides has excellent slag removal, eliminates slag entrapment associated with older generations of T-8 wires, and offers high-impact strength at low temperatures to resist cracking and minimize rework. Hobart Brothers also said the XLR-8 wire offers a stable arc and a flat bead profile with a large voltage window to improve both operator comfort and productivity in out-of-position welding applications.

Similarly, ESAB Welding & Cutting Products (www.esab.com), a global manufacturer of welding and cutting equipment, and welding filler metals, has developed what it calls a revolutionary cored welding wire. Esab said its Dual Shield wire provides excellent weld metal quality, high deposition rates, and ease of operation at low costs for mild steel and low-alloy applications. The company said its Dual Shield product could cut costs as much as 60 percent compared to coated electrodes."