Meaning and test methods for testing the tensile strength and elongation of bare wire

For bare wire, tensile strength and elongation are one of the important mechanical and bare wire conductor products performance, is the relationship between product quality and can bear the external force size of the important symbol. Tensile 

strength, and elongation of size and material properties, processing method, and heat treatment conditions.

1 sample preparation

1) the number of specimens is generally not less than three roots. The length of the specimen for the gage length plus jaw clamping length on both ends.

2) and wooden tool to specimen straightening by hand. Try to avoid making specimens under tensile mechanical damage, distortion, etc.

3) as an elongation test specimen, shall be marked in the middle of the specimen gage length (200 mm). The gauge wire should be thin and clear. The error of the gage length: hard line for + / - 0.20 mm; Soft line for + / - 0.50 mm.

4) large non-circular cross-section specimen width, can also be processed width smaller specimens. For the size of the specimen see GB 228 "metal tensile test method" regulation.

Two test methods

1) the tensile testing machine should be not more than plus or minus of error of 1%.

2) the specimen vertical clamp mouth clamping in the machine. Gauge wire should be jaw. And the axis of the specimens should be with the center of the jaw.

3) tensile speed: soft state specimen is not more than 300 mm/min.

B.for hard specimen is not more than 100 mm/min.

4) no impact on the smooth loading speed must be uniform.

5) specimens after tensile, recorded the largest load, and take effective number three.

6) the specimen fracture alignment clamping, measure, and record after stretch gauge length. If a fracture from a marked line is less than 20 mm or outside the gauge length and elongation did not meet the requirements, should take another specimen test again.

3 test results and calculation

1) tensile strength = when the tensile load (N) (was)/test specimen section, accurate to 1 mph.

2) elongation = (snap gage length after Lu - stretching before the gauge length of L0)/stretch before the gauge length of L0. The elongation calculation is less than 5%, to 0.1%; More than and equal to 5%, to 1%.

3) take no fewer than three specimen calculation data of the arithmetic mean, as test results.