WELDING

Welding is often done on structures in the position in which they are found and in the position in which the part will be used.

Often that may be on the ceiling, in the corner, or on the floor.

Techniques have been developed to allow welding in any position. Some welding processes have all-position capabilities, while others may be used in only one or two positions.

All welding can be classified according to the position of the workpiece or the position of the welded joint on the plates or sections being welded.

The American Welding Society has defined the four basic welding positions as shown below.

• Flat position
• Horizontal position
• Verticle position
• Overhead position

Any conversation around welding starts with a discussion on the welding position of the weld face.

A number is used to define the position and an F for Fillet or G for groove refers to the type of weld.

An architect’s blueprints would indicate the welding symbol.

• 1 refers to a flat position – either 1F or 1G
• 2 refers to a horizontal position – either 2F or 2G
• 3 is a vertical position – either 3F or 3G
• 4 is an overhead position – either 4F or 4G

Flat Position (1G Or 1F)

This type of welding is performed from the upper side of the joint. The face of the weld is approximately horizontal.

Flat welding is the preferred term; however, the same position is sometimes called downhand.

Note: The axis of a weld is a line through the length of the weld, perpendicular to the cross section at its center of gravity.

Flat Position Welding Procedures

In order to make satisfactory bead welds on a plate surface, the flare motion, tip angle, and position of the welding flame above the molten puddle should be carefully maintained.

The welding torch should be adjusted to give the proper type of flame for the particular metal being welded.

Narrow bead welds are made by raising and lowering the welding flare with a slight circular motion while progressing forward.

The tip should form an angle of approximately 45 degrees with the plate surface. The flame will be pointed in the welding direction.

To increase the depth of fusion, either increase the angle between the tip and the plate surface, or decrease the welding speed.

The size of the puddle should not be too large because this will cause the flame to burn through the plate.

A properly made bead weld, without filler rod, will be slightly below the upper surface of the plate. A bead weld with filler rod shows a buildup on the surface.

A small puddle should be formed on the surface when making a bead weld with a welding rod. The welding rod is inserted into the puddle and the base plate and rod are melted together. The torch should be moved slightly from side to side to obtain good fusion. The size of the bead can be controlled by varying the speed of welding and the amount of metal deposited from the welding rod.

Several types of joints are used to make butt welds in the flat position.

Tack welds should be used to keep the plates aligned. The lighter sheets should be spaced to allow for weld metal contraction and thus prevent warpage.