Different types of welding joints

Written by ron sardisco
  • Share
  • Tweet
  • Share
  • Pin
  • Email
Different types of welding joints
Technician using the arc welding process. (the electric welding image by Victor M. from Fotolia.com)

Welding is the fusing of two metal parts together such that they become one.The function of welding joints is to join metal parts together so they function as one. While many specific procedures exist for welding that use a multitude of different types of equipment, only five different types of welding joints exist. The joint type is more a function of location and purpose rather than technique or strength as in the case of wood joints. The five different types of welding joints are edge, lap, butt, corner and "T."

Butt Joint

Butt joints are used when two pieces of metal of the same thickness are joined along their length so that each is the extension of the other. Examples would be two flat bars 1 inch wide welded together to form a single bar just over 2 inches wide. Another example would be two sections of pipe joined into one longer section.

Different types of welding joints
Welding a butt joint. (welding project image by leemarusa from Fotolia.com)

Edge Joint

Edge joints are generally used on thinner metals, most commonly sheet metal less than 1/4-inch thick. The edges are welded together so that the two pieces remain parallel or nearly parallel but do not exceed 45 degrees.

Different types of welding joints
Using an edge joint on steel roof. (a construction worker welding steel image by Pavel Losevsky from Fotolia.com)

Lap Joint

A lap joint is used to fuse different thicknesses of metal together by overlapping them. This type of welding joint is strongest because it increases the thickness of the material. A rule of thumb is that the lap should be at least three times the thickness of the thinnest member of the joint. When welded on either surface, this type of joint yields a piece of metal as thick as the sum of the two pieces it joins. In cases of extreme load, a lap joint may be used in addition to a butt joint to increase the overall strength of the section.

Different types of welding joints
Many lap joints are often used to reinforce an arch. (homme de dos image by Clément Billet from Fotolia.com)

Corner and T Joints

Corner and T joints are nearly identical except for placement. These types of welding joints are used to connect pieces at right angles. The corner welding joint is used to join two plates at their edges that result in the shape of an "L." The T welding joint is used when one piece must join another away from the edge, thus forming a joint in the shape of its namesake letter.

Different types of welding joints
T joint assembly. (soudure image by RomainQuéré from Fotolia.com)

Don't Miss

  • All types
  • Articles
  • Slideshows
  • Videos
  • Most relevant
  • Most popular
  • Most recent

No articles available

No slideshows available

No videos available

By using the eHow.co.uk site, you consent to the use of cookies. For more information, please see our Cookie policy.