CENTRAL GLASS FIBER CO., LTD.  

Breaking strength / elongation of Glass cord

1. Specimen
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. Preparation
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.
2.2 Extensometer
Video type non-contacting extensometer
(DVE-201 SIMADZU CORPORATION)
2.3 Preparation
(1) Specimen holders are mounted on tensile strength test machine with spacing of 2502.5mm.
(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.
3. Measurement
Measurement of breaking strength and elongation is made with the speed of 250mm/min crosshead speed
simultaneously.
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.