Welding is often performed on structures in the position which they are found.
A Welding position is referred to as the position of the welding operator along the direction of the workpiece to be welded.
This welding position directly affects the flow of the molten metal. Therefore, it’s very crucial to understand the different types of welding positions as different welding methods are required to be performed at certain positions of the welder.
Welding is classified based on the section being welded or according to the position of the welded joint. They’re four basic welding positions, this and more we will be discussing in the next paragraph.
Welding Position Terminologies
Most conversations about welding usually begin with a discussion on welding positions. Conventionally, a number is used to describe the position and a letter is used to indicate the type of weld ( “F” for Fillet and “G” for Groove).
- 1 refers to a Flat position (either 1G or 1F)
- 2 refers to a Horizontal position (either 2G or 2F)
- 3 refers to a vertical position (either 3G or 3F)
- 4 means overhead position (either 4G or 4F)
Different Types of Welding Positions
The Four Basic types of welding positions are Flat, horizontal, vertical, and overhead welding positions.
Let us discuss these types of welding positions in details.
1. Flat Position Welding
In the flat welding position, the welding is performed on the top side of the joint. However, the actual face of the weld is approximately horizontal. In this position, the molten metal draws downward into the joint. This results in faster, easier and stronger weld. This same type of welding position is also sometimes referred to as “Downhand position”.
Note; Axis of a weld is a line through the length of the weld perpendicular to the cross section at its center of gravity.
Flat Position welding procedures:
In order to deliver satisfactory bead welds on a plate surface, the tip angle, flare motion, and the position of the welding flame must be carefully maintained. Meanwhile, the welding torch has to be also adjusted to give the exact type of flame needed for the type of metal to be welded. In order to make narrow bead welds, the flare should be raised and lowered with a circular motion as you move. The tip should also form an angle of about 45 degrees with the plate surface.
To increase the fusion’s depth, you should either decrease the welding speed or increase the angle between the tip and plate surface. The size of the puddle should be made as small as possible because the opposite of that could cause the flame to burn through the plate.
When making bead welds with a welding rod, a small puddle should be formed on the surface. The rod is inserted into the puddle while the base plate and the rod are melted together. In order to obtain good fusion, the torch should be moved slowly from side to side. The size of the bead can be managed by varying the welding speed as well as the amount of the metal being deposited from the welding rod.
(a) 1F position
The flat fillet position (1F) is performed in a situation where the filler is rotated to level will the ground. 1F is the easiest welding position.
(b) 1G position
The Groove Position Welding is performed in a situation where the groove weld is rotated in such a way that the filler material goes flat.
Out of Position Welding:
Aside Flat welding position, all other welding positions are referred to as out of position welding. This is because they’re more difficult and require one to possess a high level of skill to do them neatly. The out of position welding are Vertical, Horizontal, and overhead positions.
2. Horizontal Position Welding
This is one of the out of position welding positions. it is a more difficult position compared to the flat position. In Horizontal welding position, the weld axis is nearly horizontal, but the actual weld type dictates the complete definition.
(a) 2F position
2F is a fillet weld position. In this position, welding is done on the upper side of an approximately horizontal surface that lies against a surface that is approximately vertical. In this position, the welding torch is held at an angle of about 45 degrees. This type of welding is employed where the fillet weld is rotated in order for the filler material to level Horizontally to the ground. 2F welding position is little harder compared to the 1F position. This is because of the tendency of the molten metal to flow down to the lower side of the joint. Also, the heat emanating from the torch rises to the upper side of the joint. Combination of these two opposing factors makes it very hard to apply a uniform deposit on the joint.
2F welding on a Tee-Joint
First, align the plates and then tack weld at both ends. As the welding progress, the welding torch should be moved with a slight oscillation up and down in order to equally distribute the heat on both sides of the joint, holding the molten metal in a plastic state. Doing so will help prevent the excessive flow of the molten metal to the lower side of the joint, thereby, encouraging faster solidification of the weld metal.
Welding in a horizontal position requires regular practice more than the previous techniques. However, it is very important to master this technique before moving on to other types of welding positions.
(b) 2G position
In 2G position, the weld axis lies in a horizontal plane while the face of the weld lies approximately on a vertical plane. The vertical groove welding is employed where the groove weld is rotated so that the filler material goes Horizontally. The 2G position is a bit harder to weld as compared to 1F, 1G and 2F positions.
3. Vertical Position Welding
In vertical position welding, the axis of the weld lies approximately vertical or completely vertical, but the actual welding is laid in a horizontal position. The 3G and 3F refer to vertical groove and vertical fillet positions.
When welding in a vertical position, force of gravity pushes the molten metal downward. Therefore, it has a tendency of piling up. To prevent this from happening, you can use either the downhill or an upward vertical position.
To prevent the molten metal from piling up in the upward vertical position, you should point the flame upward and hold it at an angle of 45 degrees to the plate. This allows the welder to use the lower parts of the workpiece to weld against the force of gravity.
(a) 3F position
The vertical Fillet (3F welding position) is employed where the fillet weld is rotated so that the filler material lies vertically to the ground. The welding is progressed in an uphill manner. This type of welding position is harder to perform compare to 1F and 2F.
3F welding on a lap joint
Because this type of welding is a bit difficult to perform, the overflow of the molten metal is controlled by pointing the flame towards an angle of 45 degrees to the plate, and holding the rod between the molten puddle and the flame. This manipulation helps to keep the metal from falling down and also ensures excellent penetration and fusion of the joint. Both the welding rod and the torch should be slightly oscillated up and down in order to deposit a uniform bead. The rod should be held slightly above the center line while the flame sweeps the molten metal across the joint for even distribution.
(b) 3G Position
In 3G welding position, the welding torch is moved vertically up and down across the joint surface in contrast to the 1G, 2G, and the 4G welding positions. The 3G position has the advantage of moving faster than the other types of positions. Meanwhile, it’s too difficult to achieve deeper penetration in the 3G position.
4. Overhead Position Welding
In this position, the welding is carried out from the underside of the joint. This welding position is the most difficult and complicated position to work in. In overhead position, the metal deposited on the joint tends to fall on the plate, this results to producing a bead with a higher crown. In order to prevent this from happening, the welding puddle should be kept as small as possible. Sufficient filler should be added to have a good fusion with some extra reinforcement at the bead. But if the puddle happens to be too large, the flame should be removed to allow the molten metal cool down. When welding light sheets, puddle size is managed by supplying an equal amount of heat to the filler rod and the base metal.
(a) 4F position
The 4F welding position is employed where the fillet weld is rotated such a way that the filler material is above you flat with the ground. This out of welding position is harder and more difficult than the rest fillet position (1F, 2F, and 3F).
4F welding on a lap joint
In this technique, the flame is applied directly in order to melt both edges of the joint at a time. Enough filler metal is added with enough reinforcement in order to maintain adequate puddle. During this process, welding flame should be used to support the molten metal. Also, the operator should be too careful to regulate the amount of heat passed through the plates to avoid overheating.
(b) 4G position
The 4G welding position is employed where the groove weld is rotated in such a way that the filler material goes in overhead. This position is particularly very difficult on plate material.
Other Types of Welding Positions
Pipe Welding Positions
The welding positions Flat, vertical, overhead and horizontal are the four basic types of welding positions. These four welding positions do not however adequately define pipe welding positions. Pipe welding can be performed under many different requirements and welding conditions. The type of job dictates the welding position. Generally, the position is fixed. However, it may be rolled for flat position work.
(a) Horizontal Fixed Weld.
Horizontal pipe welding position is a fixed weld position, here the axis of the pipe is nearly horizontal, and the pipe is not in any case rotated while welding.
(b) Horizontal Rolled Weld
As the name implies is performed in a flat position by rotating the pipe.
Horizontal Pipe Welding: the Uphand Method
As you weld in the horizontal fixed position, you’ll weld in this manner:
Start from the bottom (from 6 o’clock position) and move to the 3 o’clock position.
Then start again from the 6 o’clock position and weld up to the 9 o’clock position.
Then go back to the 3 o’clock position and weld up to the top and finally overlap your bead.
Note: arc welding is the most preferred method while using the downhand method. This is because arc welding produces an electric with a higher amount of temperature giving you the ability to weld up to 3 times the speed of the upward or uphand welding method.
Q 1. What are the common terminologies used to describe different welding positions?
Conventionally, a number is used to describe the position and a letter is used to indicate the type of weld ( “F” for Fillet and “G” for Groove).
1 refers to a Flat position (either 1G or 1F)
2 refers to a Horizontal position (either 2G or 2F)
3 refers to a vertical position (either 3G of 3F)
4 means overhead position (either 4G or 4F)
Q 2. What are the differences between Groove and Fillet welds?
A groove weld is so called because a groove is usually made between the plates to be welded. Such type of weld is used for developing an edge and corner joints or butt joints. The groove preparation for thick plates allows adequate access of heat source to the root of plates thereby ensuring proper melting of the faying surfaces. Such a groove help in developing a sound weld joint.
While a Fillet weld is a closed weld. In this type of weld, the base metal is not cut through. In most of the cases, no bevelling or any other extra steps are to be performed before welding. This type of welding requires less joint preparation, just a clean surface and a good fit-up. A fillet welding is commonly performed on two plates which are perpendicular to one another. A fillet weld is subdivided into different types: these include lap joints and T-joints. Some variations of corner joints can also be considered fillet welds.
In most cases, fillet welds are frequently employed in automatic welding situations. Groove welds are highly complex and therefore more difficult to automate compare to fillet welds. Because of this reason, fillet welds are most preferred for many applications.
Q 3. What is the difference between single and double groove weld?
Single groove simply means edge preparation of the plates to create the desired groove from one side only. This results in only one face and one root of the weld. A single groove weld is mostly used for plates whose thickness is between 5 to 15 mm. Other factors that may call for single groove weld include the type of welding process used and other welding parameters.
While in the case of double groove weld, the edge preparation is done on both sides of the plates to be welded. A double groove edge preparation is mostly used under 2 conditions.
- When the thickness of the material to be welded is above 25mm. In this case, the desired penetration up to the root is not achieved from one side.
- When distortion of the weld joint is to be controlled. Moreover, double groove edge preparation reduces the volume of the weld metal to be deposited by about 50 percent compared for that of a single groove weld, most especially in the case of thick plates.
Q 4. A double V-groove joint in a thick Pipe requires one to weld from both sides. Is there preference as to which side to weld first?
Definitely yes. As the pipe is thick, the best welding process to use is either SAW or GMAW method. Both the methods provide high weld deposition rate. In order to achieve a high-quality weld, a root pass must be laid down from inside of the pipe first.
Q 5. Is it possible to Arc Weld mild steel to Stainless steel?
Yes, very possible. However, this is done with certain precautions.
Firstly, the stainless steel has to be of a certain composition and not susceptible to sensitization. If not, its corrosion resistance properties will be impaired by welding.
Secondly, if the mild steel element is thick, it’s customary to weld on it, a layer of stainless steel (type 312 or type 309) or a high nickel filler metal. This procedure is referred to as buttering.