Technical Help
Standard procedure for measuring wire elongation.
High-strength, black annealed automatic baling wire for use with automatic tiers requires an elongation of greater than 25% in order to reduce the incidence of wire breakage as much as possible. (The reasons for this are explained in our Technical Help #1)
Elongation, which is a measure of the wire ductility, is generally determined in the tensile test. The elongation is measured by marking with paint a distance on the wire between the jaws of the tensile machine holding the wire sample (called gauge length), and then comparing this distance after fracture by fitting together the two broken pieces.
The amount of stretch is converted to percent elongation by the following formula:
new length after fracture - original length
% elongation = -------------------------------------------------------- x 100
original length
Elongation at fracture is not distributed uniformly along the length of the wire sample, and will, therefore, vary with gauge length. Therefore, when comparing the elongation of different wire samples, it is most important that the same gauge length is used. The standard gauge length in the wire industry is 10 inches.
If you would like us at any time to check the elongation and tensile strength of your wire, please send us two samples each, 12 to 14 inches long. Samples sent for testing should not be bent or previously used. There is no charge for this service and we will not ask for the source of you wire samples.
