Inadequate clearance can affect weld quality and efficiency. In extreme cases, obstructions may cause a lack of fusion between the base metal and the weld metal, causing a reduction in strength. Although flux cored arc welding (FCAW) and gas metal arc welding (GMAW) have replaced shielded metal arc welding (SMAW) as the primary fabrication processes for structural steel fabrication, existing clearance recommendations are based on the SMAW process. Because the geometry of a FCAW or GMAW welding gun is much different from that of a SMAW electrode, the historic values recommended for the SMAW process may not apply to FCAW and GMAW. Experimental specimens were fabricated with the FCAW process to determine practical limits on connection geometry for welding joints with limited access. Each specimen was evaluated by sectioning and etching the weld at two locations along the length. Two weld clearance issues are addressed: (1) fillet welding near obstructions and (2) doubler plate welds. The obstructed fillet weld specimens were used to determine the minimum clearance requirements for joints welded with the FCAW process. The cross-sectioned welds showed that as the distance between the weld and the obstruction plate decreased, both the production efficiency and the penetration into the base metal decreased. Revised clearance recommendations for FCAW and GMAW welding were proposed. The doubler plate specimens were used to provide information regarding the root-pass penetration for square-cut plates, based on the plate thickness and the distance from the inner surface of the flange to the edge of the plate. The results of this study, which was limited to only eight specimens, validated the common practice of cutting the edge square at doubler plates less than 3/8 in. thick. For doubler plates thicker than 1/4 in., a groove angle, alpha, of 15 degrees to 30 degrees may be required to ensure consistent weld quality.
