Copyright Goodheart-Willcox Co., Inc. 132 Gas Tungsten Arc Welding Handbook move across the joint evenly. Movement of the torch by the fi ngers alone usually results in incorrect torch angles and a poor weld. Torch angles are very important to maintain and understand. The torch angles control the heat of the arc, and the weld pool moves where it is directed by the torch angles. Two different torch angles, the work angle and the travel angle, greatly affect how the weld bead is placed into the weld joint. The work angle is the angle of the torch in a plane that is perpendicular to the weld axis and is measured from the perpendicular position to the torch’s actual position. See Figure 8-6A. Work angles usually split the weld pool evenly between the two pieces of base metal. When the work angle points to one side of the joint more than the other, the weld moves in that direc- tion. For example, on a fl at butt joint, the work angle is 90°, straight up and down into the joint. Work angles are generally straight into the middle of the joint. The weld pool will show if the weld is favoring one side or the other. If this happens, the welder must adjust the work angle to correct the uneven weld. The travel angle is the angle of the torch in the plane parallel to the weld axis and is measured from the perpendicular position to the torch’s actual posi- tion. See Figure 8-6B. The torch should always be pushed in the direction of the weld. Torch travel angles are usually 15° to 20°. The main reason to main- tain a good travel angle is so that the welder can see the weld pool. The welder must be able to see the weld pool when making any weld. The actual weld pool is much smaller than the ceramic cup on the end of the torch, so the torch must be laid over so the weld pool can be seen. However, travel angles that are too severe can suck air into the weld from the back side, causing porosity or other discontinuities due to atmospheric contamination. For welding butt joints in any position, the suggested work angle is generally 90°. Because the work angle is perpendicular to the workpiece, it provides maximum penetration. The suggested travel angle for welding butt joints is typically a push angle Figure 8-5. Holding the torch in the manner shown allows the welder to move the torch easily to change torch angles. (Mark Prosser) Work angle Filler rod angle Travel angle A — End View B — Side View Figure 8-6. Welders must be mindful of the travel angle, work angle, and filler rod angle. A—This end view of a fillet weld in progress shows how the work angle is measured. B—This side view of a fillet weld in progress shows how travel angle and filler rod angle are measured.