Breaking strength / elongation of Glass cord
|The specified number of bobbin shall be sampled from one lot.
The specimen shall be taken above sampled bobbins in 10m after 1m is rejected.
|2.1 Specimen holder lined with rubber
|Two rubber-lined rings are prepared for specimen holder.
When rings are not lined with rubber, a code cuts on a ring and an exact result is not obtained.
|Video type non-contacting extensometer
(DVE-201 SIMADZU CORPORATION)
|(1) Specimen holders are mounted on tensile strength test machine with spacing of 250±2.5mm.
(2) Approx. 2m of glass cord is taken from bobbin without breakage of a specimen.
(3) A specimen is wound on an upper holder in 3 times clockwise without touch of cords.
(4) An end of specimen described in (3) is put in a space between two pipes of upper stopper
and wound on lower pipe in 3 times counterclockwise without touch of cords.
(5) An end of specimen is cramped between two pipes by screwing.
(6) Similarly, the other end of specimen wound on lower holder in 3 times clockwise without touch of cords.
(7) An end of specimen described in (6) is put in a space between two pipes of lower stopper
and wound on lower pipe in 3 times clockwise without touch of cords.
(8) An end of specimen is cramped between two pipes by screwing.
(9) Ruler is applied to the specimen stretched between up-and-down holders, and two marks are put on it
at intervals of 50mm using a white paints pen.
|Measurement of breaking strength and elongation is made with the speed of 250mm/min crosshead speed
Two specimens per one bobbin are measured.
The breaking strength shall be read to 0.01kgf. Elongation at breaking shall be read to 0.001mm(L).
|4. Calculation and report|
|The average breaking strength of two measurements of specimens taken from one bobbin,except the strength
breaking at clamp, is reported in N to integer or to the first decimal place.
The elongation at breaking calculated to the first decimal place as follow.