FAQs Orbital Q & A 1. What welding process is used in orbital welding equipment? Orbital welding equipment primarily uses the GTAW (TIG) process because of the repeatability that it affords. Within the orbital GTAW process there is autogenous fusion, cold wire, and hot wire. Autogenous fusion welding is the rotation of the tig arc around the work piece simply fusing the base material. Cold wire orbital systems have a wire-feeding system that mechanically add filler metal as the arc travels. Hot wire involves rotating the arc around the workpiece while mechanically adding almost molten filler metal. 2. What type of bevel should I have on pieces to be welded orbitally? That depends on the wall thickness of the tube or pipe to be welded. For wall thickness of .154 and under a square butt joint can be used with the fusion process. For wall thicknesses above .154, filler metal should be added and a J-bevel or a standard bevel with EB rings should be used. The J-bevel offers better fit-up (fit-up is crucial for orbital welding) than a traditional 37.5 or 45 degree bevel. Generally, the lands on the J bevel should be .060" thick and .060" long. An EB ring is a consumable insert that is tacked to each of the beveled ends and is consumed in the root pass. 3. What shielding gas should be used for orbital welding? Different metals require different types of shielding gases. For most orbital welding applications 100% Argon is used. Occasionally 95% Argon/5% Hydrogen and various helium mixtures are used in applications where additional heat input is required. Other gases such as nitrogen may be used as a purge gas on exotic materials like duplex’s. 4. How much does a robotic system cost? Robotic arms or robotic cells have a straightforward dollar value. This number is representative of the quality of the robot and the welding equipment attached. The addition of tooling is the part of the robotic system that is difficult to predict and the largest cost factor in turnkey installations. It is not unusual for the tooling to cost as much as if not more than the robot itself. 5. How important is joint fit-up in robotic applications? As is the case with any type of automatic welding, the quality of the weld is dependent on the consistency of fit-up. Tracking and oscillation hardware will overcome some poor fit-up issues, however there is a trade off in speed, heat input, and distortion. Every effort should be made to ensure quality fit-up of the parts to be welded. continued...