What does the number '70' indicate in terms of tensile strength in welding?

The number '70' in relation to tensile strength in welding specifically indicates a tensile strength of 70,000 PSI (pounds per square inch). This is a standard way of denoting the strength of weld materials, particularly for filler metals and welding materials. In this context, welders and engineers use the number to categorize and specify the quality and strength of welds that can be achieved with particular materials.

For example, a filler metal labeled with a '70' designation is expected to have the capability to withstand a tensile stress of 70,000 PSI before breaking, which is crucial in ensuring the integrity and durability of welded structures. This clear and concise labeling system allows welding professionals to choose the appropriate materials depending on the strength requirements of the project they are working on, maintaining safety and performance standards in structural applications.