What is the likely weld progression for the first pass on a 3F weld on 10 mm (3/8") material?

For a 3F weld, which refers to a vertical fillet weld, the appropriate progression for the first pass on 10 mm (3/8") material is typically downhill, especially when you are working with material of this thickness.

When welding in a downhill progression, the welder moves the electrode downward along the joint. This can be advantageous for several reasons. First, when welding downhill, the molten weld pool tends to flow with gravity, which can help create a more controlled and flatter bead. This is particularly beneficial in vertical welding, as it minimizes the risk of excessive buildup and ensures better penetration, especially on the first pass.

Additionally, downhill welding generally offers increased travel speeds, which can be useful in maintaining a competitive production rate without compromising the quality of the weld. This method can result in good fusion and penetration into the base material while still allowing for enough control to create a strong joint.

While there are instances where other progressions might be necessary, for the first pass on vertical welds in practical applications, downhill is favored for efficiency and ease of control.