![]() ![]() T-1 wires provide good wetting action and are generally reserved for less critical applications because they don’t offer the best toughness. Some of the most common flux-cored wires with rutile slag systems include those classified under AWS A5.20: Specification for Carbon Steel Electrodes for Flux-Cored Arc Welding and feature the designators of T-1, T-9 and T-12. Basic slag systems are highly effective at lowering weld metal oxygen, providing superior weld metal toughness but low freezing temperature slags. Wires with a basic slag system are composed of minerals of alkali elements, such as fluorspar, limestone, magnesite or dolomite. However, wires with a rutile slag system don’t possess the mechanical properties to achieve low temperature toughness compared to their basic counterparts. They’re considered to have excellent welder appeal because they’re easier to use than flux-cored wires with a basic slag system, particularly out of position. Wires with a rutile slag system have good weldability with low spatter and a soft arc. Rutile slag systems are composed mostly of titanium dioxide from the mineral rutile along with other minerals such as silica, alumina or zircon. Each system has advantages and limitations. Wires with higher levels of silica tend to generate slag that’s more difficult to remove, while those with higher levels of lime have slag that’s easier to remove.įlux-cored wires are available with rutile (acidic) or basic slag systems, each of which impact weldability, including arc performance. However, too much titanium can make the slag sticky. For example, wires with higher levels of titanium dioxide (TiO2) have faster freezing slag, which makes the wire better for welding out of position. The flux inside of both gas- and self-shielded flux-cored wire impacts the way slag behaves. There, the elements solidify into slag that includes nonmetallic elements, such as oxides of aluminum, silicon and calcium oxides and that may also pull nitrogen, hydrogen and some carbon out with it. Through thermodynamic processes, elements that aren’t included in the formation of the weld pool are essentially pushed out and forced to the surface. Slag forms when the heat from the arc breaks down the filler metal and the base material to form a molten weld pool. It also helps keep the molten weld pool in the joint as it cools, which is especially important for out-of-position welding. It protects the weld from oxidation and contamination from the atmosphere. Some filler metals, however, are formulated with self-peeling slag that releases from the weld on its own. Removing slag is a mechanical process completed with chipping hammers, wire brushes or wheels, or needle scaler. It can have a slightly different makeup depending on process or product. It’s also present in shielded metal arc welding (SMAW), submerged arc welding (SAW), and other welding and brazing processes. The American Welding Society (AWS) defines slag as “a nonmetallic byproduct of the mutual dissolution of flux with nonmetallic impurities in welding and brazing processes.” In short, it’s the hardened layer left on the top of the weld made during flux-cored welding (FCAW). Slag by Definition, Purpose and Chemistry ![]() So, what exactly is slag and what does it do? It plays an important role in ensuring good weld quality, and the various slag systems also impact a wire’s welding characteristics. Welders may know slag as a bothersome byproduct of gas- and self-shielded flux-cored processes because it frequently requires chipping or grinding to remove it after welding or between passes. Lubricants, Coolants, Metalworking Fluids. ![]() Computerized Maintenance Management Systems.Abrasives, Belts, Brushes, Grinding Wheels. ![]()
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