Tensile strength

Stress is a term used to describe tensile strength. Stress is calculated as force per unit area. A force or a force per unit width can be stated for some non-homogeneous materials (or for completed components). The unit of measurement in the International System of Units (SI) is the pascal (Pa) (or a multiple thereof, frequently a megapascal (MPa), with the SI prefix mega); or, equivalently, newtons per square metre (N/m2). Pounds per square inch (lb/in2 or psi) is a unit used in the United States. Kilopounds per square inch (ksi, or occasionally kpsi), which are frequently used to measure tensile strengths, are equivalent to 1000 pounds per square inch (psi). A tiny sample with a defined cross-sectional area is typically pulled with a tensometer at a constant strain rate (change in gauge length divided by starting gauge length) rate until the sample breaks. Indentation hardness and tensile strength have a linear relationship when testing various metals. This significant relationship enables the nondestructive assessment of bulk metal deliveries using light, even portable equipment, such as handheld Rockwell hardness testers, which is economically significant. This useful correlation enables quality control in the metalworking industries to go much beyond the lab and standard testing equipment.