D.E.

I Technical College Dayal bagh Agra

Topic-

Edge prepration in welding and welding positions

Submitted bySonu Kumar 116251 Mechanical

Edge Prepration in welding

JOINT ARRANGEMENTS AND WELDS The edge preparations are arranged to make the weld joint. The pieces to be welded may be connected or a gap between the pieces to ensure penetration may be used. On most joints the gap is at the bottom of the joint and is referred to as the root of the joint. The term root opening or open root is used to describe this condition. For example; Open root V groove, or V groove with an open root. When the joint design allows, a backing strip or insert may be used for easier welding. Some joints may have a backing weld, or back weld applied. A back weld is applied after the groove is filled. A backing weld is applied before the groove is filled.

THE FIVE BASIC JOINTS There are five basic joints in common use for assembling metal. 1. BUTT JOINTS 2. T JOINTS 3. LAP JOINTS 4. CORNER JOINTS 5. EDGE JOINTS

1. BUTT JOINTS A butt joint is formed when the pieces to be welded are laid side by side and it is one of the most widely used types of joint.

The names in the examples above are from the type of weld applied to the joint. Often the type of weld is used to fully describe the joint. For example; this joint is a single bevel butt joint.

The V groove and bevel grooves are easier to prepare and are used more than the J or U groves. .

2. T JOINTS A T joint is formed when one piece of metal to be welded is placed vertically on another piece lying horizontally, to form the shape of an inverted T.

The vertical member is usually placed at 90 deg to the horizontal member. One of the most widely used types of weld applied to a T joint is the fillet weld. When a single pass or multiple passes are made against the joint, the weld resembles a Triangle when viewed from the side.

The T joint and fillet weld are the most frequently used joint and type of weld. In the same way the edges of the butt joint may be prepared for welding, the tee joints vertical piece may be prepared using a Bevel, or J shape. The preparation allows the Welder to penetrate into the root of the joint. See examples below:

3. LAP JOINTS A Lap joint is formed when one piece to be welded is laid down and another piece is overlapped to form an edge for fillet welding or an area to allow plug or slot welding. Lap joints are often used when plug or slot welding thinner sections. A plug weld is made by welding holes evenly spaced across the length of one or both sides of the joint. A slot weld is similar except slots are made instead of holes. Other welds may be applied to laps such as projection, or seam welding. See examples below:

LAP JOINTS

4. CORNER JOINTS A corner joint is formed by placing one piece to be welded on the other so that a corner is formed. The corner may be Flush; Half Open; or Fully Open. An edge preparation may be applied to one, or both of the pieces of the joint for penetration and strength.

5. EDGE JOINT An Edge joint is formed when the two edges of the pieces to be welded come together. This joint may be formed as a result of another structural shape and is not as widely used as some of the other joints. See examples below.

Welding Positions
The welding position are classified as follows Flat position-In this position, the filler metal is deposited from upper side of the joint with the face of the joint horizontal. Horizontal position-In this position, the weld is deposited upon the side of a horizontal and against a vertical surface. Vertical position-In this position, the line of welding is in a vertical plane and the weld is deposited upon a vertical surface.

 Overhead position-In this position, the weld is deposited from the underside of the joint and the face of the weld is horizontal.