Tensile Testing

A test procedure that determines the tensile strength and tensile properties of a material. To perform this test, a bar is machined from the material to be tested. The bar can be machined from an actual part or component or it can be made from stock that will be used to manufacture a component. Test bars vary in size but are generally about six inches in length or smaller, depending on the amount of material available. Round cross section test bars are use to test castings, forgings, wrought bars, and other three dimensional shapes. Flat cross section test bars are used to test plate, sheet, and strip materials.

machined Round TensileMachined Round Tensile Specimen

Hydraulic Tensile Test MachineTypical Hydraulic Tensile Test Machine

To perform the test, the bar is placed in the test fixture, with clamps securing each end. Using mechanical or hydraulic force, the bar is then “stretched” or pulled and the “stretching” response of the bar is recorded. The test is usually continued, with the amount of force increased, until the bar breaks. The tensile strength of chain, wire, and wire rope can also be determined by tensile testing as well as the tensile strengths of plastics, rope, and other materials. In addition to tensile strength, tensile testing can determine properties such as yield strength, elongation, and reduction in area.