Learn to identify 6G welding, the most commonly used kind of weld to test a welder for certification. The letter "G" stands for the type of weld, which is a grooveweld and the number "6" designates the position of the pipes welded. A grooveweld is a joint in two metal pipes where the space in between them is filled up with the welding material.
The 6G Welding Position
Welds are of three main types; flat welds are the easiest to make, horizontal welds more difficult and vertical welds are the most demanding. This is because the molten filling metal flows downwards during the welding process, pulled by gravity into the joint cavity. In a vertical weld this may occur too quickly, so it requires much practice. In welding, a 6G position requires one pipe to be positioned at a 45-degree angle to the other. Both are horizontal. This presents a very challenging position for a welder, who uses all his skills and a variety of body positions to accomplish the most difficult weld in the 6G join: the overhead weld.
The 6G Welding Test
The 6G welding test, also known as the Arkansas bellhole test, is a means to identify the skills or lack of them in a welder. It's stringent test, because the welder must use a variety of techniques, such as flat, vertical and horizontal welding to achieve a successful 6G weld. 6G welds are made by workers in trades like steel working that require skilful welding ability. When a welder can produce a good 6G weld, he is tested on it and receives certification when he passes this test.
Why G6 is the Most Difficult of Welds
This weld is considered the most difficult type of weld to perform because it requires welds that are made in all positions using both hands. It also simplifies testing, removing the need for testing each position used to perform a 6G weld individually.
What are 6G Welds used for?
Groove welds, including 6G welds, are used on all kinds of joints except for joints constructed from two overlapping pipes, known as lap joints. It's rare a certified welder will encounter pipes requiring 6G welds while working, but it's a common pre-employment test.
What is a 6GR Test?
A 6GR test is a variant of the 6G test. The conditions are all the same as the 6G test, with one additional factor. The letter "R" in 6GR stands for restricted and means the test weld is performed with a ring made from steel plate placed an inch under the weld site. This extra degree of difficulty tests the ability of a welder to make a joint where impediments, such as brackets, attach the pipe to another structure or wall.