4F position overhead fillet welding . In this orientation, the welder works from the underside of a joint where one plate is horizontal and the other is vertical, forming a "T" or lap joint. Miller Welding Technical Overview Classification
An interesting and highly relevant research paper on the 4F (overhead fillet) welding position is "Prediction of Welding Parameters and Weld Bead Geometry for GMAW Process in Overhead T-Fillet Welding Position (4F)" by Yaakub et al.. 4f welding position full
. To the uninitiated, it’s simply "overhead fillet welding". To those under the helmet, it’s a high-stakes battle against physics, where gravity is your constant adversary and molten metal is looking for any reason to rain down on your jacket. 4F position overhead fillet welding
Defy Gravity: Gravity pulls the molten metal down. To counter this, maintain a tight arc and keep the weld pool small to prevent dripping or sagging. Rod Angles: Clean your metal
To understand 4F, we must break down the alphanumeric code used by the American Welding Society (AWS):