How to choose between V or J Bevel?

Let us return to the question of the bevel, which will reduce the thickness of the tube in order to allow welding. Generally speaking, a tube with a wall thickness of more than 3 mm cannot be welded with only one layer in TIG welding.

TIG welding is a Tungsten Inert Gas process: Tungsten designs the electrode and Inert Gas the plasmagenic gas used for shielding.

In order to weld thicker pipe, a bevel must be carried out at one edge of the tube to be welded to another pipe / bend / reduction / connections (T,Y), which also have to be bevelled.

The bevelling systems often are of “manual” type.

J or Tulip bevel

The other technical way of bevelling is called “bevel for orbital welding” and this one is different compared to the J or tulip bevel.

• The shape of the bevel used for orbital welding is different as it has a flat land at the edge of the J or tulip bevel with a thickness of 1,8 to 2 mm. This land will facilitate smoothing and straightening.
• The act of smoothing and straightening consists of realizing a plane reference enabling the machining of the other faces. In this way a finer thickness will be created in the inner side of a tube. Example: A thickness of 8 mm before bevelling and only 2 mm remaining for the land.
• The two lands of the workpieces with a land thickness of 2 mm will be in contact. Only a simple fusion of the lands will be necessary and afterwards the bevel can be filled with filler wire using orbital welding technology.

V Bevel

On the other hand if you choose a “V”-bevel, you will plane the two pieces to be welded in this form. In this shaved groove in V-form the welder looks for a welding penetration. In order to do so he creates a weld puddle on the inner part of this “V” in order to fill the material that has been removed

How can I choose between a “V or a “J” bevel?

The “V” bevel is used for manual welding. Whereas, the orbital welding processes more commonly use the “J” bevel preparation.

In order to make a “V” or a “J” bevel you can find different shapes of tool bit with a “V” or “J” shape.

Making a “J” bevel for manual welding is of no interest, as the angle is too large for a manual procedure. The choice of the bevel essentially depends on the welding process.

Advantages of an orbital bevelling machine

An orbital bevelling machine has certain advantages:

1. the execution of the bevel is very quick, with only one pass around the pipe – a clean bevel without any burr.
2. The carbide tool does not modify the nature of the material.
3. The rejection rate is very low thanks to the precision of the tool which makes high quality end preparation.
4. The bevel angles in “V” shape can be carried out in three different degrees: 30, 37,5 and 45°.

The orbital bevelling technology allows you to choose between two beveling preparations which have been successful.

The orbital bevelling is part of the global process: from orbital cutting to final welding. Interested? Here you can download our handbook on orbital TIG welding free of charge!