Posições de Soldagem e Tipos de Junta: 1G, 2G, 3G, 4G, 5G e 6G

Welding Positions and Joint Types: 1G, 2G, 3G, 4G, 5G, and 6G

Welding, as a general process, has many intricate details that must be configured to achieve a positive final result.

There are various ways to ensure that you do everything correctly. Experience plays a part, but a significant portion relies on technical documentation. Weld operators are seldom simply instructed to join two pieces of material at a 90-degree angle. Instead, they receive a WPS, or Welding Procedure Specification, which is a document specifying all the critical details related to the welds that need to be made.

Among the many pieces of information in this document is the type of weld. This is usually denoted by a combination of letter and number, such as 1G or 4G, or something a bit more complex, like 6GR.

What do these designations mean? Understanding their definitions is a fundamental part of ensuring that you are welding correctly. So, let's go through the essential information you need to know.

What Does the Number Mean?

The welding specification consists of a letter-number pair, making it easy to analyze and define each element individually.

The number is the simplest to interpret. Different welding specification standards, such as AWS, ASME, and ISO, have different names for their data tables, but the general information remains consistent across the board.

There are six numbers that are labeled from 1 to 6, which specifically refer to the position being used during welding.

They are:

• 1. Flat. Flat welding is performed beneath the torch. It's one of the most common, easiest to manage, and least complex welding positions. Since you're working from above, visibility is good. As the workpiece isn't at an awkward angle, you don't need to worry about the weld pool flowing out of position or the risk of drips from above.
• 2. Horizontal. This position is more commonly used for overhead welds where two workpieces align on the same plane. The horizontal position means you're moving sideways across the weld instead of pushing or pulling towards or away from yourself, as in position one.
• 3. Vertical. This means that the materials are positioned in front of you so that you need to move up or down along the seam to weld a joint. These are generally specified as PF or PG for upward and downward. Downward is particularly common and good for productivity, as you aren’t fighting gravity as much as in other positions.
• 4. Overhead. This is one of the most challenging and dangerous welding positions. Welding overhead requires holding your torch above you in a way that you can weld safely without risking personal injury or damage to the workpieces. Experienced operators should handle this type of welding unless machinery is utilized.
• 5. Pipe welding. The fifth specification is complex because there are upward and downward labeled positions referred to as PH and PJ in the ISO nomenclature. As pipe welding necessitates the circumference of a pipe, it passes through flat, vertical, and overhead positions. The difference between upward and downward is their starting point; upward begins at the bottom and ends overhead, while downward does the opposite.
• 6. Another form of pipe welding, specification six, is required for certification welding. It's a combination of all the more complex elements of welding; it's pipe welding, so you must pass through all other positions in a smooth motion while aligning two pipes at a 45-degree angle, adding an additional challenge to the entire process.

Again, number designators are primarily used in AWS documentation; other standards, like ISO, use different names for the same processes, sometimes with additional granularity.

Are There Special Considerations for Specific Numbers?

Of course. Different positions present various challenges. While 1G is generally regarded as the simplest and easiest weld, every other type of weld presents its own challenges.

For example, welding in 2F is more challenging than welding in 1F due to the molten metal flowing downwards, with the torch heat rising above the joint, preventing a consistent deposit from being applied to the joints.

For better welds, welders need to align the metals and weld them at both ends. The torch movements should be slightly up and down to spread heat evenly on both sides of the joint, preventing the molten metal from flowing to the bottom side of the joint, solidifying the weld metal quicker. To master, welding in 2F or any horizontal position requires a lot of experience. 2F is one of the horizontal positions for angle testing.

What Does the Letter Mean?

Now that you know what the number signifies, you can learn what the letter means. As you may guess, it’s another component of the overall welding specification. Since we're discussing 1G, 2G, 3G, 4G, 5G, and 6G, a simple definition for G is provided.

G stands for Groove Weld.

That’s it! Simple, right? Well, not so fast. There are some complications regarding this.

The first complication is that G isn’t the only letter; it’s just the sole one in the title of this post. While we could stop here technically, that wouldn't be very educational, would it?

There are two other letters that arise.

F stands for Fillet.

Groove welds and fillet welds are the two most common types of welding. The main difference between them is simply where the weld joint occurs on the workpiece. If there is a gap between the two pieces, filled with melted filler material in the weld pool, that is a groove weld. Groove welds can be performed on pieces that are not in contact with one another, or the surfaces can be prepared with a bevel or grinder.

Conversely, if two materials are in contact without any gaps and the filler material is deposited outside the weld, that is a fillet weld. You can read much more about this and even see diagrams of them in action here.

Comparing AWS and ISO

AWS and ASME use the same designations, while ISO has its own. Here is the conversion:

• 1G or 1F is PA
• 2F is PB
• 2G is PC
• 4F is PD
• 4G is PE
• 3G upward is PF
• 3G downward is PG
• 5G upward is PH
• 5G downward is also PH
• 6GR is PH or PJ, depending. Generally, it is also specified as L045.

The reason why 5G upward and 5G downward are both PH is that, from a physical and mechanical perspective, the operation is identical, as in ISO nomenclature, neither the direction nor the starting point matter, just the operation itself.

For more detailed insights, you can check further articles and resources.

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