Welding Inspection & Metallurgy API ICP Self Study Notes

The tensile specimen is punch marked in the central section of the specimen,
and measured, and the diameter of the reduced area prior to subjecting it to
the tensile load is measured. After the specimen has been fractured, the two
halves of the fractured tensile specimen are fitted back together as closely as
possible, and the distance between the punch marks is again measured. The
increase in the after-fracture gage length as compared to the original gage
length prior to subjecting the specimen to tensile loads is the elongation of the
specimen. This is usually expressed as the percentage of elongation within 2
in. (50.8 mm) of gage length. The diameter at the point of fracture is also
measured and the reduction in area from the original area is calculated. This
reduction in area is expressed as a percentage. Both the elongation
and the reduction in area percentage are measures of a material’s ductility.