4G Welding Position Explained

Written By: Liam Bryant

In 4G welding, welders work on a vertical groove weld on a plate, one of the basic welding positions. It’s a position that tests a welder’s skill and is vital to many welding certifications.

welding positions

What is 4G Welding Position

The 4G welding position is one of the four basic welding positions used in plate welding. When people refer to ‘4G,’ they specifically talk about a vertical groove weld. The plate is set up vertically when working in this position, and the groove weld is applied on the joint.

This kind of welding position is often considered the most challenging among the four types of positions: flat (1G), horizontal (2G), vertical (3G), and overhead (4G).

I remember first encountering the 4G welding position during my welding certification process. I was working on a mobile welding services project at that time, and mastering the 4G position was crucial for my work.

Where Do You Use 4G Welding

4G welding is primarily used when making a joint on a vertical plate. Typically, these are locations where the structure or the equipment you’re working on doesn’t allow for the part to be moved or rotated. Examples could include large structures, construction beams, or heavy equipment repairs.

During my time in the welding industry, I’ve seen the 4G welding position used in diverse places from shipyards to skyscrapers. Once, I was even part of a project where we had to perform a vertical weld on a hefty industrial boiler – a task that definitely tested my skills!

Characteristics Of The 4G Welding Position

Welding in a 4G position requires the welder to weld from bottom to top. This means you’re fighting against gravity, which makes the process more challenging.

One distinctive characteristic of the 4G welding position is the shape of the welds you’re likely to produce. When welding in a 4G position, you typically create groove welds. These welds are made in the groove between two pieces of metal.

As a welder, I’ve found that groove welds require precision and steady hands, especially when the bead of molten metal per second has to be consistently controlled in this vertical position.

What is the Qualification Range for 4G

The qualification range for 4G includes vertical welding of groove welds and fillet welds in all positions. This means that a welder who passes a 4G welding test is also certified to weld in 1G, 2G, 3G, and 4F positions.

Preparing for my 4G welding test was an intense process. The certification process includes both practical and theoretical components. I was handed a coupon (a test piece of metal), and had to produce high-quality groove and fillet welds under the watchful eyes of a certified welding inspector.


One of the main advantages of the 4G welding position is the broad qualification range it provides. As I mentioned earlier, passing the 4G welding test qualifies you for all basic welding positions, which opens up more job opportunities.

4G welding also allows for great flexibility in the field. Since you’re working on a vertical surface, you can tackle welding projects in various environments and configurations.


The 4G welding position also has its challenges. The biggest one is the difficulty of the task. Welding against gravity requires skill, control, and patience. And producing quality groove welds in this position is not an easy feat.

Another downside is the potential for increased safety risks. Overhead welding can lead to hot sparks or molten metal falling down, which requires welders to take extra precautions.

4G vs 4F Welding Positions

The main difference between the 4G and 4F welding positions is the type of welds. The ‘G’ in 4G stands for ‘groove,’ which means you’re creating groove welds vertically. On the other hand, ‘F’ in 4F stands for ‘fillet,’ which refers to welding fillet joints in an overhead position.

Though both positions are part of the vertical and overhead categories, the 4G welding position is generally considered more challenging due to the precision and control required to create groove welds.


The 4G welding position is a fundamental technique that every welder should strive to master. Its broad qualification range and flexibility make it a critical skill in the welding industry. Despite its challenges, I’ve found that the effort put into mastering the 4G welding position has been more than worth it. It has opened up countless opportunities in my welding career and made me a more skilled and versatile professional.