ISO 7622-1-2013 pdf free download

ISO 7622-1-2013 pdf free download.Steel cord conveyor belts — Longitudinal traction test — Part 1:
Measurement of elongation
Courroies transporteuses a cables d’acier — Essai de traction dans le sens longitudinal — Partie 1: Mesurage de lallongement.
4.3 Extensometer, accurate to at least 0,01 %.
As the elongation of steel cords is generally very low, accurate, but sensitive, extensometers, which could be damaged if the test specimen should break, have to be used. For this reason, the measurement is limited to 60 % of the specified tensile strength.
It is preferable that an extensoineter be able to accommodate the cord rotation which occurs due to its twisted nature.
4.4 Device for recording the curve of traction force as a function of elongation, if available.
5 Test specimens
Prepare four specimens (two S-twist and two Z-twist) as follows:
a) take a sample at least 400 mm long from the belt;
b) using a knife, cut the compound between the layer of cords and the remainder of the belt;
c) then cut the compound so as to isolate the cords from the central part and extract four cords, taking care not to subject them to any tensile stress;
d) strip the rubber coating from the whole cord length or at least from the area at the end of each of these cords that is to be placed in the holding device.
6 Procedure
Carry out four tests at least five days after manufacture of the belt.
Unless otherwise specified, in which case note this fact in the report, carry out the test at 23 °C ± 2 °C and at 50 % ± 5 % relative humidity in accordance with ISO 18573, Atmosphere B.
Place the ends of the cord on the holding device, as follows:
a) fix one end on the upper device;
b) fix the other end on the lower device, and apply an initial tractive force equal to 50 times the linear density (mass per metre) of the cord (this is to define the zero point of the registration curve clearly);
c) position the two jaws of the extensometer with a separation of between 100 mm and 300 mm.
Start the dynamometer, with the rate of separation of the jaws maintained constant at 25 mm/mm ± 5 mm/mm.
Record and note the elongations at 10% and 60 % of the specified minimum tensile strength of the belt in the number of cords.
7 Expression of results
Express the elongation as a percentage of the initial length.
Take as the result the arithmetic mean value of the four measurements made at 10% and at 60% of the specified minimum tensile strength.
Express the result to the nearest 0,1 %.
8 Test report
The test report shall contain the following information:
a) a reference to this part of Iso 7622, i.e. Iso 7622-1;
b) the mean values of elongation at 10 % and 60 % of the specified minimum tensile strength, in accordance with Clause 7:
c) any operating details not specified in this part of ISO 7622, or regarded as optional, together with any incidents likely to have influenced the results.ISO 7622-1-2013 pdf free download.