QC/T 1162-2022Honeycomb sandwich structure products for automobile exterior trim parts (English PDF)

3.1 Damage load

The force value, at which a specimen is damaged, when it is subject to the bending strength test, according to the provisions of GB/T 1456-2005.

3.2 Flexure stiffness

The ability of a specimen to resist deformation, under a bending load.

4.1 Structure

Honeycomb sandwich structure products for exterior decoration parts are composed of: exterior panels (ABS, ASA, PC/ABS, PMMA and other materials or composite panels composed of two or more materials), glass fiber reinforced polyurethane foam materials, honeycomb core material (paper honeycomb, polypropylene honeycomb, aluminum honeycomb or other honeycomb structure materials), etc.

4.2 Classification

Honeycomb sandwich products are divided into the following three categories, according to the mass per unit area:

- Category a: Products which have a mass per unit area of less than 3000 g/m2 AND are suitable for products with a bending stiffness higher than 9 x 10^6 N·mm2, such as battery covers, etc.;

- Category b: Products which have a mass per unit area of 3000 g/m2 ~ 4500 g/m2 AND are suitable for products with a bending stiffness higher than 12 x 10^6 N·mm2, such as roof spoilers, side spoilers, engine compartment covers, etc.;

- Category c: Products which have a mass per unit area greater than 4500 g/m2 AND are suitable for products with a bending stiffness higher than 14 x 10^6 N·mm2, such as lower door trim panels, top covers, rear doors, etc.

5.1 Appearance quality

The outer surface of the product shall be smooth and flat, without defects such as collapse and cracks, or other defects that affect the service life.

5.2 Product performance

Product properties shall meet the requirements of Table 1.

6.4.2 Room temperature

Take a pretreated product. Conduct the test, according to the requirements of 6.4.1, at 23 °C ± 2 °C.

6.4.3 Long-term heat resistance

Take a pretreated product and place it in an incubator at 80 °C ± 2 °C for 168 hours.

After taking it out, place it in an environment of 23 °C ± 2 °C for 0.5 hours. Conduct the test according to the requirements of 6.4.1.

6.4.4 Resistance to cyclic cold & heat

Take a pretreated product and put it in a high & low temperature test chamber. Take (80 ± 2) °C x 4 h -> (23 ± 2) °C x 1 h -> (-40 ± 2) °C x 4 h -> (23 ± 2) °C x 1 h as one cycle; carry out 4 cycles of tests. After taking it out, place it at 23 °C ± 2 °C for 0.5 h. Carry out test, according to 6.4.1.

6.4.5 Damp resistance

According to the provisions of 5.4.2 in QC/T 15-1992, take a pretreated product and put it in a humidity test chamber, at a temperature of 55 °C ± 2 °C and a relative humidity of (95 ± 5)% for 168 h. After taking it out, place it in an environment of 23 °C ± 2 °C for 0.5 h. Conduct the test according to the requirements of 6.4.1.

6.5 Bending stiffness

6.5.1 Sampling method

Take 5 specimens from the test product. The sampling position shall be selected as far as possible at a flat center position, which is more than 20 mm away from the edge. The specimen size is as shown in Table 3. The length, width, thickness of the specimen are accurately measured by a caliper which has an accuracy of 0.02 mm.

6.7 Resistance to cyclic cold & heat

6.7.1 Test method

Take three pretreated products and put them into the high & low temperature test chamber. The test conditions are in accordance with the provisions in 6.4.4.

6.7.2 Appearance quality and dimensional change rate

Visually inspect the product for abnormal phenomena, such as deformation, warping, delamination, etc. Test the dimensional change rate, according to the provisions in 6.6.3.

6.8 Damp resistance

6.8.1 Test method

Take three pretreated products and put them into the damp test chamber. The test conditions are in accordance with the provisions in 6.4.5.

6.8.2 Appearance quality and dimensional change rate

Visually inspect the product for abnormal phenomena, such as deformation, warping, delamination, etc. Test the dimensional change rate, according to the provisions in 6.6.3.

6.8.3 Weight change rate

Carry out the damp resistance test, according to the provisions in 6.4.5. Use weighing tools, which have a division value not greater than 1 g, to weigh the pre-test mass and post-test mass of the three products, respectively. Calculate according to formula (3).

The test results are taken as arithmetic mean of 3 test data. The result retains one decimal place.

Where:

epsilon - Weight change rate, %;

m1 - The weight before the test, in grams (g)

m2 - The weight after the test, in grams (g).

6.9 Cold impact resistance

Take three pieces of pretreated products. Place them in a low-temperature box at -40 °C ± 2 °C for 24 h, according to the provisions of 5.1.4.3 in QC/T 15-1992. Take them out.

Within 5 s, use 500 g ± 10 g steel balls to impact the outer surface of the product.