Which type of weld is characterized by a roughly triangular shape?

A fillet weld is characterized by its roughly triangular shape, formed at the joint between two pieces of metal, typically at right angles to each other. This shape allows for effective filling of the gap between the two surfaces, providing strength and stability to the joint. Fillet welds are commonly used in structural applications, as they can join different types of joints, including lap joints and corner joints, making them versatile and widely utilized in various welding scenarios.

The triangular shape of the fillet weld maximizes the contact area between the weld metal and the base materials, which contributes to the overall strength of the connection. This geometrical configuration also helps to distribute stress along the welded joint, making it less prone to failure under load.

In contrast, a bevel weld involves a prepared edge on the base materials to create a beveled joint, sufficient for deep penetration welding, resulting in a different, more elongated shape. A butt weld joins two pieces of metal end-to-end, typically resulting in a flush finish without an external shape, while a spot weld creates small, localized fusions between overlapping surfaces, which would not have a triangular form.