Test method for physical and mechanical properties of special industrial rope belts

1 Scope

This standard specifies the test methods for physical and mechanical properties of special industrial woven ropes and belts (including cotton, silk, hemp and chemical fiber ropes).

This standard is applicable to the physical and mechanical property test of general special industrial ropes. If there are other special requirements for ropes, they shall be specified in the quality standard of the rope, or otherwise agreed by both parties.

2 Reference standards

The following standards contain provisions that, through reference in this standard, constitute provisions of this standard. When the standard is published, the versions shown are valid. All standards will be revised. All parties using this standard should explore the possibility of using new versions of the following standards.

GB 8170-87 Rules for Rounding off Numerical Values

3 Sampling

3.1 Sampling proportion

3.1.1 Sampling for physical and mechanical property test of rope belt shall be conducted in batches and bundles according to different product numbers and use requirements.

3.1.2 The quality identification samples of the manufacturer shall be taken from the products produced by the same product number and the same machine (for example, the same processing process shall also be paid attention to for post processed ropes). When they are used for aviation, 25~100% of the bundles shall be taken from each batch according to the quality stability. When they are used for other purposes, 10% of the bundles shall be taken from each batch for physical and mechanical performance tests and anti burning performance tests.

3.2 Sample quantity

3.2.1 Take one rope from a bundle at random, and the rope sample can be cut at the rope head (before cutting the sample, tie two adjacent knots at the shearing position in advance, and then cut between the two knots). Each sample is about 1.6 m long, or the sampling length can be determined by oneself according to different types of strength test fixtures.

3.2.2 Take three rolls of tape in a bundle at random, and the sample can cut a strip about 0.6 m long at the head of each roll, or determine the sampling length according to different types of strength test fixtures. Three strips form a sample.

3.2.3 Specimens for anti burning test shall be cut separately, and each specimen is 0.4 m long.

3.2.4 The cut sample shall be free of various appearance defects. For example, the product after anti burning treatment shall be free of uneven dipping and rolling of anti burning agent or non application of anti burning agent.

3.2.5 After cutting the sample, the sampling quantity shall be indicated on the label of the original rope head or head.

3.2.6 Each sample cut shall be attached with a label on which the following items a) product name shall be recorded;

b) Bale number;

c) Rope coil or tape coil number;

d) Sampling time.

4 Test conditions

When measuring the weight and breaking strength, the standard atmospheric conditions of the laboratory are temperature 20 ± 3 ℃ and relative humidity 65 ± 5%. The sample shall be spread and placed under the above specified temperature and relative humidity conditions for 24 hours, and the test shall be conducted under this condition.

5 Test items

5.1 Width

5.1.1 Test tools

5.1.1.1 Scale for general tape (including sleeve tape) accurate Steel ruler to 0.5 mm.

5.1.1.2 For thick tapes with double and multi-layer structures with rounded edges and a thickness of more than 2 mm, use vernier calipers with a scale accurate to 0.1 mm.

5.1.2 Operation steps

5.1.2.1 The belt width shall be measured once at the middle of each sample within the tolerance range, three times in total.

5.1.2.2 When measuring with a steel ruler, place the sample flat on the workbench, align the "0" point of the ruler with the band edge, and read the width perpendicular to the band edge accurate To 0.5 mm.

5.1.2.3 When measuring with a vernier caliper, hold the tape with one hand and the ruler with the other hand, insert the tape into the caliper jaw, and then slowly clamp the caliper jaw, so that there is no gap between the caliper jaw and the belt edge, and the tape can move freely between the caliper jaw. At the same time, pay attention to that there is no concave and convex deformation on the belt surface, and read its width and reading accurate To 0.1 mm.

5.1.2.4 The average is calculated to 0.1 mm and rounded to 0.5 mm (rounding method: 0.2 and below are rounded off, 0.3~0.7 is calculated as 0.5, and 0.8 and above are calculated as 1).

5.1.2.5 The width measurement method of hollow rope after flattening is the same as that of ordinary belt.

5.2 Thickness

5.2.1 Test tools

5.2.1.1 Y-531 fabric thickness gauge, scale accurate To 0.01 mm.

5.2.2 Operation steps

5.2.2.1 Each sample shall be measured three times, one in the middle of the sample, and the other two at about 100 mm from the top of the sample.

5.2.2.2 Chassis area: 6.5 cm ² when the bandwidth standard is 40 mm or less; When the bandwidth standard exceeds 40 mm, 10

cm²。

5.2.2.3 Place the sample horizontally in the middle of the upper and lower chassis of the thickness tester, raise the hanging wall to 2~3 mm above the strip thickness, and let it fall freely. For three consecutive times, record the last reading accurate When it is 0.01 mm, the average is calculated to 0.001 mm and rounded to 0.01 mm.

5.3 Total number of warp wires (or number of braids and cores)

5.3.1 Operation steps

Cut off about 20 mm of the sample, draw out the warp (or braid, core) of the whole sample, and count its pieces.

5.3.2 Expression of results

The braid, core and warp of different fabric structures of the rope shall be indicated separately.

5.4 Weft density (or braid number)

5.4.1 Test tools

5.4.1.1 Fabric density analysis mirror for rope.

5.4.1.2 When the weft density of the belt is 8 pieces/cm or less, use a steel ruler, and when the weft density is more than 8 pieces/cm, use a fabric density analysis mirror.

5.4.2 Operation steps

5.4.2.1 The rope shall be measured on each sample for three times. One is in the middle of the sample, and the other two are about 200 mm from the top of the sample

5.4.2.2 The tape shall be measured once in the middle of each sample for three times. The double-layer structure and tape sheath only measure the weft density of the surface line.

5.4.3 Measurement range

The measuring range is specified according to the measured length given in Table 1.

Table 1 Measured length of each time

5.4.4 Measurement starting point

The rope should be in the middle of the interweave point of the two braids. The belt should be in the middle of two weft threads. If the end point is also in the above position, one weft thread should be counted. If the end point is in the center of the yarn, the last one should be counted as one half thread. If the end point is less than one half thread, it should be counted as one half thread. If the end point is more than one half thread and less than one thread, it should be counted as one half thread. The reading should be accurate to one half thread. The weft density result should be converted to the unit of expression specified by the standard.

5.5 Weight

5.5.1 Test tools

5.5.1.1 Industrial balance with a sensitivity of 0.01 g.

5.5.1.2 The length is more than 1 m, accurate Non folding ruler with accuracy of 1 mm.

5.5.2 Operation steps

5.5.2.1 Each sample shall be tested once.

5.5.2.2 Place the sample horizontally on the test bench in a natural state.

5.5.2.3 Rope: measure a certain length of the sample along the edge of the ruler, cut off the excess part, and tie knots on both ends.

5.5.2.4 Tape: measure a certain length on each sample along the warp direction of the sample, and cut off the excess.

5.5.2.5 Weigh and read on the balance accurate To 0.01g, then convert to 1m weight, 1m weight to 0.01g, rounded to 0.1g.

5.6 Breaking strength and elongation

5.6.1 Test instruments

Strength testing machine with elongation measuring device.

5.6.2 Instrument selection and calibration

5.6.2.1 The use range of the dial of the strength tester shall be within 20~80% of the full scale.

5.6.2.2 The distance between the upper and lower clamps of the strength testing machine is 20 cm when measuring the longitudinal breaking strength of the rope and belt; When measuring the zonal breaking strength of the belt, the width of the belt is 5 cm when it is more than 100 mm, and 2.5 cm when it is 100 mm or less.

5.6.2.3 When the lower clamp is not under load, the descending speed is 100~110 mm/min.

5.6.2.4 The strong pointer and extension pointer shall be at the "0" point.

5.6.2.5 The inside and outside of the upper and lower clamps shall be pasted with good gaskets, and powdered rosin can be sprinkled between the sample and the gasket to avoid slipping.

5.6.2.6 The pre tension weight shall be hung according to the configuration given in Table 2.

5.6.3 Operation steps

5.6.3.1 When testing ropes, each sample shall be tested three times. When testing the tape, each sample shall be tested once and three times in total.

5.6.3.2 For the belt with larger width, according to the index requirements, after the sample is cut, the yarn on both sides is removed and trimmed to a certain width of the test strip. The standard tolerance of the width is 1/2 yarn based on the middle position of the test strip. For fabrics whose yarns are easy to slip out during the test, 2~4 protective wires shall be left on both sides of the test strip, and the two ends of the protective wire shall be cut off. The test strip shall not be clamped by clamps, and the weft test strip shall not be long enough for the upper and lower clamps to fully clamp and hang the pretension weight

Table 2 Pretensioning weight  

Sew other belts to make up the necessary test strip length.

5.6.3.3 During the test, first put down the holder, fix the upper clamp, align one end of one rope or three strips, and then put them in the center of the upper clamp at the same time (if there is a difference between the test results of both parties, a sample shall be put into the upper clamp), and initially tighten the upper clamp, Then put the other end of the sample into the lower clamp (when there is a core rope in the test, the sample can be tightly wrapped with canvas or tightly woven cotton tape, and then put into the clamp for clamping), hang the pretension weight, slightly loosen the upper clamp (not loosen when there is a core rope in the test), make the sample slightly drop and become vertical due to gravity, that is, tighten the upper clamp, loosen the clamp, Then tighten the lower clamp and remove the pretension weight for test. If it is necessary to measure the elongation at break, after the lower clamp starts to fall, pay attention to observe the elongation at the moment of breaking (for the double-layer strip with the core passing through the unstructured point, it should be at the moment of the core breaking, that is, the elongation at the moment of the first separation of the two strength indicators), and record the breaking strength and elongation at the same time. If it is necessary to measure the standard elongation, pay attention to the strength pointer. When it turns to the standard strength of the object to be measured, stop the decline of the extension scale and record its elongation, but the lower clamp still continues to decline. Do not stop in the middle until the sample breaks, and read the strength number. The reading of breaking strength and elongation shall be read to the minimum scale of dial and ruler.

5.6.3.4 Calculate the average to 0.1N and 0.01%, and round to 1N and 0  1%。

5.6.4 Precautions

5.6.4.1 If the sample slips or breaks at the clamp mouth (within 10 mm from the clamp edge) during the test, another sample shall be replaced and the test shall be repeated. If the breaking strength has reached the index requirements, it is not necessary to repeat the test.

5.6.4.2 In case of any abnormal phenomenon (including test readings and machinery, etc.) during the test, the test shall be stopped immediately to check and analyze the cause.

5.6.4.3 During operation, prevent the sample in the clamp mouth from twisting and skewing.

5.6.4.4 During the test, the "0" point of the strong pointer and the extension pointer shall be frequently observed, and timely adjusted if there is any change.

5.6.4.5 The "stress" point of the suspended pretension weight shall be parallel to the jaw without deflection.

5.7 Anti burning performance

5.7.1 Test instrument

CIA anti burning tester

5.7.2 Test preparation

The friction wheel should be wrapped with 514 or 528 brocade plain silk after anti burning treatment. Replace it every 30 tests. If the wrapped silk is damaged at any time within 30 tests, replace it immediately.

5.7.3 Test operation

5.7.3.1 Check and set test parameters

a) Linear speed of friction wheel: 50 ± 1.5 m/s;

b) Start time: 5 s; c) Working time: 5s;

d) Friction contact length of test strip: 10 mm for belt and 4 mm for rope.

  Table 3 Preloading counterweight

5.7.3.2 Check and replace the wrapped silk strips on the friction wheel.

5.7.3.3 Clamp one end of the test strip in the splint, and hang the counterweight on the other end as required, and make it fall on the pulley.

5.7.3.4 Cover the protective cover, close the power switch, and press the start button.

5.7.3.5 After the motor power is automatically cut off, open the protective cover, mark the test strip, and remove the test strip.

5.7.4 Precautions

5.7.4.1 The pre added counterweight of the test strip shall be hung according to the provisions given in Table 3.

5.7.4.2 During the test, it is necessary to regularly check and correct the working time, starting time and knob position.

5.7.4.3 Do not put any foreign matter in the instrument cavity, and clean the debris frequently.

5.7.4.4 In case of abnormal sound during the test, press the stop button immediately for inspection.

5.7.5 Evaluation of anti burn test results

5.7.5.1 Burns without sintering are qualified.

5.7.5.2 In case of local mild burns, the content of anti burning agent can be measured according to the fat content test method. When the content of C-1 anti burning agent is more than 2%, it is qualified.

6 Synthesis and retest of test results

6.1 If any index of the sampled test result does not conform to the standard, double number of samples shall be cut from the original sampling point for retest of the item. The retest result is qualified if both samples conform to the standard.

6.2 If the manufacturer finds that a rope or a reel of tape is still not up to the standard after retest, the other ropes or reels of tape can be sampled one by one or tested one by one, and the test results shall be subject to one time, and retest is not allowed.

6.3 When calculating the average, the rounding method shall follow the provisions of GB 8170.