QC/T 1043-2016Nylon tubing for automotive fuel systems (English PDF)

7.3 Test of density

Use the method A (impregnation method) in GB/T 1033.1-2008 to carry out test.

7.4 Test of melting temperature

Follow the requirements of GB/T 19466.3-2004 to carry out test.

7.5 Test of extractable components

7.5.1 Test preparation

Use the wire mesh as specified in GB/T 6003.1-2012 for the extraction. The pore size is 0.5 mm and 3.15 mm, to limit the size of the particles. Use the ethanol which has a purity of more than 99.5% as the extract.

7.5.2 Test device

The schematic diagram of extractor is as shown in Figure 1.

7.5.3 Test procedure

The test is carried out as follows:

a) Bake the extraction vessel and the round-bottom flask at 105 °C for 1 h. Move it to room temperature to cool it. Weigh the mass of the extraction vessel m0, accurate to 0.1 mg;

b) Then put the required specimen into the extraction vessel. Weigh the mass m1 again. Generally take 7 g ~ 8 g of specimen, accurate to 0.1 mg. Put the extraction vessel into the extractor;

c) In the round-bottom flask, add the extract and zeolite. Move the round-bottom flask in an electric heating jacket. Use a test tube clamp and test tube holder to fix the whole equipment. Correctly install the water inlet and water outlet of the cooler. Open the faucet switch to allow the water to completely flow through the cooler;

d) Turn on the power supply of the electric heating jacket. Adjust the heating power of the electric heating jacket, to ensure that the extractor produces 4 overflows per hour. After one overflow is finished, start time-keeping;

7.6.1.1 Specimen

Take 5 pieces of nylon hose or assembly of nylon hose which has a free length of 300 mm.

7.6.1.2 Test device

Testing machine of burst pressure.

7.6.1.3 Test procedure

Carry out test at the ambient temperature of (23 ± 2) °C. Make the assembly of nylon hose be full of liquid (water of hydraulic oil). Then at the rate of (7 ± 1) MPa/min, apply pressure to the assembly of nylon hose, until it bursts. Record the maximum pressure during the test.

7.6.2 High-temperature burst test

7.6.2.1 Specimen

Take 5 pieces of nylon hose or assembly of nylon hose which has a free length of 300 mm.

7.6.2.2 Test device

Testing machine of burst pressure.

7.6.2.3 Test procedure

Make the assembly of nylon hose be full of liquid (water of hydraulic oil). Maintain it at (100 ± 5) °C for 1 h. Then at the rate of (7 ± 1) MPa/min, apply pressure to the assembly of nylon hose, until it bursts. Record the maximum pressure during the test.

7.7 Test of impact strength

7.7.1 Specimen

Randomly take 5 specimens which have a length of at least 50 mm. Carry out test under the following conditions:

a) The impact rate is 3.6 m/s ~ 4 m/s (optimally 3.8 m/s) and impact energy is 7.5 J.

b) The temperature is (23 ± 2) °C and (- 40 ± 3) °C. For the test at -40 °C, the specimen is cooled for at least 4 h;

c) The spacing of the support surfaces of the pendulum impact tester: 40 mm.

7.9 Test of UV durability

Randomly take 3 specimens which have a length of 150 mm. Follow the cycle 1# in Table 4 of ISO 4892.3-2006 to carry out test. The time of exposure is 504 h (42 cycles). Remove the specimen, place it for 30 min. Follow the requirements of 7.7 to carry out the test of impact strength at room-temperature.

Note: Subject to the agreement between the user and the manufacturer, the time of exposure may be as specified by the end user.

7.10 Test of fuel resistance

7.10.1 Test device

The cycle test device is as shown in 7.10 of QC/T 798.

7.10.2 Test procedure

The test is carried out as follows:

a) In the temperature control box, it shall place the as large number and length of nylon tubes as possible and connect them to the cycle test device. Use the fuel 0 # diesel to charge the cycle system. Under the following conditions, keep the specimen for 500 h:

- Fuel temperature (40 ± 2) °C;

- Temperature of temperature control box (100 ± 2) °C.

After the test, dismantle the nylon hose from the cycle test device. The surface of the specimen shall not have obvious cracks.

b) Follow the requirements of 7.6.1 to perform burst test at room-temperature.

7.11 Pullout test

7.11.1 Specimen

Take 3 hose assemblies whose one end is equipped with pipe fitting and a free length of 150 mm.

7.11.2 Test procedure

The test is carried out as follows:

a) For the ferrule-connected nylon hose, tighten the union nut of the assembly of nylon tube and the pipe joint. The tightening torque is as shown in Table 7; […]

9.1 Category of inspection

The inspection is divided into exit-factory inspection and type inspection.

9.2 Exit-factory inspection

9.2.1 Inspection items for exit-factory inspection include appearance, dimension and marking, burst pressure at room-temperature. Based on the production batch, take sufficient specimens. Then follow the requirements of this standard to carry out inspection.

9.2.2 When the ordering organization samples the product for inspection, follow the provisions of GB/T 2828.1-2012. The sampling plan and the acceptance quality level (AQL) are as agreed by the supplier and the purchaser.

9.3 Type inspection

9.3.1 Classification of type inspection

The type inspection is classified as follows:

a) Trial-type identification of new product or old product after trans-plant production;

b) After formal production, when there are significant changes in structure, materials, processes that may affect product's performance;

c) When the it resumes production after a long-term shutdown;

d) For batched or mass-produced products, not less than once per 6 months;

e) When the exit-factory inspection result is significantly different from the previous type inspection result;

f) When the national quality supervision agency proposes the requirements for type inspection.

9.3.2 Sampling

The products of the same specification as continuously produced at the same production site, the same raw materials, equipment and processes form a batch.

The products to be type-inspected shall be taken from the same batch of products that have been passed the exit-factory inspection. The sampling plan shall be as agreed upon by the supplier and the purchaser.