Most spot welds are specified by what measurement?

Spot welds are primarily specified by their diameter, as this measurement directly relates to the size of the area being fused together during the welding process. The diameter is crucial because it influences the strength and quality of the weld; a larger diameter typically indicates a greater surface area for metal fusion, which can enhance the weld's integrity.

In spot welding, achieving a consistent and optimal diameter is essential for ensuring the weld can withstand the intended loads and stresses. This size allows engineers and welders to determine whether the weld will fulfill its structural requirements in its application.

Other measurements, while relevant in a broader context, do not specifically define the spot weld in the same way. Length and depth might relate to the overall dimensions of the weld area or penetration but do not provide the same critical information about the weld's quality. Temperature is also significant during the welding process, as it affects the weld's formation and characteristics, but it is not a measurement used to specify the weld itself.