Fillet weld

Fillet welding refers to the process of joining two pieces of metal together when they are perpendicular or at an angle.

These welds are commonly referred to as tee joints, which are two pieces of metal perpendicular to each other, or lap joints, which are two pieces of metal that overlap and are welded at the edges.

The weld is triangular in shape and may have a concave, flat or convex surface depending on the welder's technique.

There are 5 pieces to each fillet weld known as the root, toe, face, leg and throat.

[2] The root of the weld is the part of deepest penetration which is the opposite angle of the hypotenuse.

[1] Fillet welding notation is important to recognize when reading technical drawings.

It is recognized that there are two different approaches in the global market to designate the arrow side and other side on drawings; a description of the two approaches is contained in International Standard ISO 2553, they are called "A-System" (which is more commonly used in Europe) and "B-System" (which is basically the ANSI/AWS system used in the US).

[4] If the weld is to be continuous around a piece of metal such as a pipe or square, then a small circle will be around the point where the flat line and arrow pointing to the joint are connected.

Examples of this are "E70" meaning the arc electrode must have a tensile strength of 70,000 pounds-force per square inch (480,000 kPa; 4,900 kgf/cm2).

When reading a manufacturers technical drawings, you might also come across weld dimensions.