Which type of seam is typically used in metal fabrication for strength?

The welded seam is considered the strongest type of seam used in metal fabrication. This strength comes from the process of joining two pieces of metal by melting them together, resulting in a continuous, solid connection that often has a tensile strength equal to or even greater than that of the base metal. This makes welded seams particularly advantageous in applications where structural integrity and durability are critical, such as in the construction of HVAC systems or other frameworks exposed to significant stress loads.

In contrast, other seam types, while they may be suitable for certain applications, do not typically provide the same level of strength as welded seams. For example, a butt seam involves bringing two edges together but may not have the same load-bearing capacity unless reinforced. A lapped seam overlaps materials but can leave gaps that weaken the bond. A flat seam, commonly used for decorative purposes or in lighter applications, offers limited strength compared to welded seams, making it less suitable for heavy-duty uses.