Lesson 2

The 4 Basic Welding Positions & types of welds

Flat Welding Position

A ‘flat’ weld is the most basic of all welding positions. This is where the weld is performed along the horizontal access, from above the joint. The flame motion should be controlled, melting the walls of the plates enough to produce a puddle of the desired size. 

Oscillating the torch tip means the molten puddle can be carried along the joint, which ensures sufficient filler is present to reinforce the weld. Care should be taken to not overheat the molten puddle as this would burn the metal and reduce the strength of the weld.

Horizontal Welding Position

The axis of a horizontal weld is along the horizontal plane, and if often used for fillet or groove welds. This type of weld is more difficult than flat weld. A potential issue for this welding position, which makes it more difficult than a flat weld, is that the molten metal can fall to the lower side of the joint and heat can rise to the upper side. 

This makes creating a uniform deposit, however oscillating the weld torch up and down distributes heat equally and prevents the puddle running down and has the additional benefit of faster solidification.

Vertical Welding Position

The vertical welding position describes a weld with the axis being vertical. This weld is more complicated than both the flat and horizontal positions, however. The main problem faced with a vertical weld is that the molten metal tends to run down the joint and pile up at the bottom. This can be controlled by angling the torch up by 45 degrees and holding the rod between the flame and the puddle. In doing so, you ensure good fusion and prevent runoff.

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Overhead Welding Position

Overhead Welding Position

The most complicated welding position, overhead, is performed on the underside of a joint. Metal deposited tends to drop onto the plate when welding overhead, as gravity takes control, but this can be combatted by keeping the molten puddle small. If the puddle does become too large, remove the flame and allow the metal to solidify in a bid to prevent dropping.

Sufficient filler metal should maintain an adequate puddle and enough reinforcement to prevent the metal from falling. The flame should melt both edges of the joint, and this would also support the molten metal further.