ISO 7802 pdf download Metallic materials — Wire — Wrapping test
This International Standard specifies a method for determining the ability of metallic wire of diameteror thickness 0,1 mm to 10 mm inclusive, to undergo plastic deformation during wrapping.
The wrapping test consists of winding a wire to a specified number of turns around a mandrel of thediameter specified in the relevant standard to form a closely wrapped helix.
lt may also include a specified sequence of winding and unwinding, or even rewinding
3 Test equipment
The testing machine shall be constructed so the wire can be wound around the mandrel in a helix so thaadjacent wraps of the coil are in contact. A piece of the wire to be tested may be used as the mandrelprovided it is of the specified mandrel diameter and of sufficient hardness
4.1 In general, the testis carried out at ambient temperature between 10 C and 35 C. Tests carried outunder controlled conditions shall be made at a temperature of 23 ·C + 5C
4.2Without applying any torsion, wind the wire in a helix tightly around the mandrel at a constant ratenot exceeding 1 wrap per second so that the adjacent wraps of the coil are in contact, If necessary, reducethe rate of wrapping to ensure that the heat generated does not affect the result of the test.
4.3 To ensure tight winding, a tensile stress not exceeding 5 % of the nominal tensile strength of thewire may be applied during winding.
4.4 When unwinding, or unwinding and rewinding, are specified, the rate shall be sufficiently slow toprevent any rise of temperature likely to affect the result of the test. At the end of the unwinding, at leastone turn shall not be unwound.
The interpretation of the wrapping test is carried out according to the requirements of the relevant4.5Standard. When these requirements are not specified, absence of cracks visible without the use otmagnifying aids is considered as suficient evidence that the test piece withstood the test. Wire with athickness or diameter less than 0,5 mm shall be examined with approximately 10-times magnification.
5 Test report
The test report shall include the following information:
a) a reference to this International Standard;
b) identification of the test piece (type of material, type of coating, etc.);
c) diameter or thickness of the test piece;
d) diameter of the mandrel;
e) test conditions (number of turns, or the wound length);
f) test result