Which of the following is not classified as a "physical property" in reference to metals?

Tensile strength is not classified as a physical property in reference to metals; rather, it is categorized as a mechanical property. Physical properties describe inherent characteristics of a material that can be observed or measured without changing the material's composition, such as ductility, thermal conductivity, and electrical resistance.

Ductility refers to the ability of a metal to undergo deformation under tensile stress, indicating how well it can be stretched without breaking. Thermal conductivity measures how well a material can conduct heat, while electrical resistance quantifies how strongly a material opposes the flow of electric current. Each of these is a physical property because they describe how a material reacts to physical forces or environmental changes without altering its fundamental structure.

In contrast, tensile strength specifically refers to the maximum amount of tensile (stretching) stress that a material can withstand before failure, making it a measure of performance under load rather than a basic physical characteristic. Understanding these distinctions helps in the evaluation and selection of materials for various applications in welding and metallurgy.