Before we can delve into what are the four welding positions, any discussion of this topic will define the position for the weld face. Welding is classified by the work piece position or the welded joint position on the sections that are being welded together. Welding can be done on a wide variety of structures in predefined welding positions which can be positioned where they will be found or used.
What Are Welding Positions?
The American Welding Society has four basic types of welding positions that it recognizes. A specific welding position is defined by a number followed by the letter “F” which stands for Fillet or the letter “G” which refers to a weld type.
| On an architect’s blueprints, welding symbol would be prominently indicated as follows: |
| 1 would be a 1F or 1G flat position. |
| 2 would be a 2F or 2G horizontal position. |
| 3 would be a 3F or 3G vertical position. |
| 4 would be a 4F or 4G overhead position. |
What Are The 4 Welding Positions
1/ Flat Welding Position
These welding positions can be 1F or 1G, they are performed at the upper side of the joint and the weld face is approximately in a horizontal orientation. The preferred term is simple “flat welding”, but some welders may refer to this as “down hand” welding. It’s important to note that the weld axis is a line that can be traced through the length of the weld. It’s perpendicular to the cross-section where the center of gravity is located.
Flat Position Welding Process
The flat position welding process on plate surfaces requires careful maintenance of the flare motion, tip angle, and the welding flame position over the molten puddle. The welding torch needs to be adjusted to produce the proper flame type of the metal that you want to weld.
Narrow bead welds are produced by moving the welding flare up and down in slight circles as forward progression is maintained. The tip should form a 45º angle with the plate surface and the flame should be pointed in the direction of the weld. An increase in the angle between the tip and the plate or a decrease in welding speed will increase the fusion depth. The puddle size cannot be too large because this will burn through the plate.
A proper bead weld with no filler rod should be slightly below the surface of the plate. If a filler rod is used to create a bead weld, this can show up as a buildup on the surface. When you make a bead weld with a welding rod, a small puddle should form. The welding rod should be inserted in the puddle, the rod and base plate are then melted together. Slight side to side movements with the torch will be needed to create good fusion. The bead size can be controlled by adjusting the amount of welding rod metal used and by varying the welding speed.
Butt Welds in Flat Welding Positions
It’s possible to use several joint types to make butt welds in flat welding positions. Tack welds can keep the plates aligned, but light sheets should be spaced to allow for contraction and prevent warping.
The flame motion must be controlled to melt plate sidewalls and sufficient amounts of welding rod to create the right puddle size. The molten puddle can be carried along the joint if the torch tip is oscillated. This ensures the complete penetration and sufficient amounts of filler metal for weld reinforcement. If the molten puddle is overheated this will cause the metal to burn, porosity can occur and the completed weld may lack strength.
2/ Horizontal Welding Position
The horizontal welding position is 2F or 2G, the weld axis is approximately horizontal, and the complete definition will be dictated by the weld type. The fillet weld is created on an upper side of a surface that’s approximately horizontal and up against a surface that’s approximately vertical. To create a groove weld, the weld face should be orientated in the vertical plane or a close approximation.
It can be a challenge to create butt welds in the flat position because the molten metal tends to flow into the lower side of a joint. The torch heat rises to the upper joint side and these factors make it difficult to apply uniform deposits to the joint. The plates must be aligned, and a tack weld is made at each end to make the surface stable.
The torch is then moved with slight oscillation up and down to promote even heat distribution on both sides. The molten metal is then held in a plastic state which prevents the flow of excessive metal to the lower side of the joint. This makes the weld metal solidification faster and the learning curve is steeper than other flat position techniques.
3/ Vertical Welding Position
These types of welding positions can be 3F or 3G and the axis of the weld will be vertical or some approximation. When you weld on a vertical surface there is always a risk the molten metal will run down and pile up. The metal flow can be controlled by pointing the flame at a 45º upwards angle to the plate surface and holding the rod between the puddle and flame.
To promote good penetration and fusion and to prevent sagging and falling, it’s important to manipulate the torch and filler rod continuously. A uniform bead is created when the torch and welding rod are oscillated.
The rod should be held above the center line of the joint slightly and the welding flame should be swept across the molten metal to create an even joint distribution. A butt joint created in the vertical position should be prepared in the same way as flat position welding.
4/ Overhead Welding Position
The overhead position welding can be 4F or 4G and the main issue is that metal tends to say or drop on the plate. The bead typically has a high crown and the molten puddle needs to be kept small to overcome this problem. Sufficient filler metal is needed to get good fusion and bead reinforcement. If the puddle is too large, the flame must be removed for a second to give the weld metal time to freeze.
Welding light sheets requires a puddle size, which can be controlled by equal heat application to the filler rod and base metal. Both edges of the joint should be melted with the flame and sufficient filler metal is needed for the puddle with adequate reinforcement.
Burning can be avoided with small welding along the joint and the flame should support the molten puddle. A rod should be used and the heat should be controlled through the plates. This is very important if you are only welding a single side.
Wrap Up– Four Different Welding Positions
Over the years, certain techniques have evolved to cover welding in virtually any position. Specific welding processes can only be used in one or perhaps two positions and others may have all-position capabilities. So, hopefully we have answered your questions about the different welding Positions that can be used.