What do the first two digits in the AWS electrode classification number indicate?

The first two digits in the AWS electrode classification number represent the tensile strength of the electrode in thousands of pounds per square inch (psi). This classification provides critical information about the electrode's strength and capability in various welding applications. For instance, if the first two digits of an electrode classification are "70," this indicates that the electrode can produce a weld with a minimum tensile strength of 70,000 psi.

Understanding this aspect of the AWS classification is important for welders because it helps in selecting the appropriate electrode for specific projects, ensuring the weld will meet structural and mechanical strength requirements. The tensile strength is a key factor in determining how well a joint can handle applied loads and stresses, making it essential for structural integrity in welded connections.