Types Of Butt Joint Welds

Types Of Butt Joint Welds

1 Tack Welds

Prevent butt joint distortion by tack weldingthe materials in position before final weld.

Workpiece distortion occurs when heat is applied locally to a joint. One side of a metal plate will “curl” up toward the weld.

Distortion will also cause the edges of a butt joint to pull together ahead of the electrode as the weld cools.

2 Square Groove Weld

3 Single V-Groove Weld

4 Double V-Groove Weld

Materials up to 3/16 in (5 mm) thick can often be welded without special preparation using the square groove weld. However, when welding thicker materials it may be necessary to prepare the edges (V-groove) of butt joints to ensure good welds.

The single or double V-groove weld is good for materials 3/16 − 3/4 in (5-19 mm) thick. Generally, the single Vgroove is used on materials up to 3/4 in (19 mm) thick and when, regardless of thickness, you can weld from one side only. Cut the bevel with  oxyacetylene or plasma cutting equipment. Remove scale from material after cutting.

A grinder can also be used to prepare bevels.

Create a 30 degree angle of bevel on materials in V-groove welding.

Butt Joint Training Procedure.

Practice welding butt joints on 1/8 in (4 mm) or thicker material. (Avoid thinner materials since they require greater skill.) Separate the squared edges of the material about 1/16 in (1.6 mm) and make a butt weld all the way through with a 1/8 in electrode. (You may need to adjust the weld current and travel speed to obtain the desired weld.) Perform a similar exercise on 1/4 in (6 mm) material, depositing a bead on each side of the joint

and fusing one to the another (no bevel needed).

Practice making a single V-groove weld on 1/4 in (6 mm) plate beveled 30°. Start with a 1/8 in electrode for the first bead and finish with a 5/32 in (4 mm) electrode.

Be sure to penetrate about 1/32 in (1 mm) beyond the bottom of the “V” or root.

Perform a similar exercise on thicker materials. Generally, deposit a bead for each 1/8 in (3mm) of material thickness, cleaning the joint between layers.

On heavier plates, it may be necessary to weave the top layers to fill the groove.