What type of joint is indicated by a square weld symbol?

A square weld symbol on a welding drawing indicates a fillet joint. This type of joint is commonly used to join two pieces of metal at a right angle, typically where one piece overlaps the other.

In a fillet joint, the weld fills the joint between the two metal pieces, providing strength and support where their edges meet. The square shape of the weld symbol signifies that the weld is to be made on the two surfaces that are joined together, forming a triangular cross-section, which maximizes the area of fusion and helps the joint withstand stresses effectively.

Understanding the purpose of the square symbol in welding can help ensure that welders create strong, reliable connections in their piping systems, adhering to safety and engineering standards essential in high-pressure piping applications.