QC/T 1090-2017Specifications of sealing gaskets for automotive engines (English PDF)

5.1 Test equipment

5.1.1 Electrothermal drying oven: 0 °C ~ 250 °C, resolution is 0.1 °C.

5.1.2 Dryer.

5.1.3 Micrometer: The working face has a diameter of 6 mm ~ 10 mm and a graduation value of 0.01 mm.

5.1.4 Vernier caliper: The graduation value is 0.02 mm.

5.1.5 Balance: The sensitivity is 0.001 g.

5.1.6 High temperature furnace: 0 °C ~ 1100 °C, the resolution is 1 °C.

5.2 Conditioning of specimen

All samples for physical property test shall be conditioned in an incubator at 100 °C ± 2 °C for 1 h, then transferred to a dryer which contains anhydrous calcium chloride to cool it to 21 °C ~ 30 °C. Then start testing.

5.3 Inspection of appearance quality

The appearance quality is checked by visual inspection.

5.4 Measurement of thickness

Use a micrometer to measure the thickness of the gasket. Uniformly measure three points on one gasket. Use the arithmetic mean as thickness measurement result.

5.5 Determination of density

5.5.1 Determination of the density of non-metallic gaskets. It is performed according to GB/T 22308-2008.

5.5.2 Determination of density deviation of graphite metal composite gaskets. It is performed according to JB/T 6628.

5.5.3 Determination of density of fiber rubber metal composite gaskets.

Cut a 40 mm × 40 mm fiber rubber metal composite gasket material test piece …

5.11.2.2 Test evaluation

If there is no peeling expansion on both surfaces of the three specimens, the test results are reported to be acceptable; otherwise they are unqualified.

5.12 Determination of corrosivity

It is performed according to GB/T 540-2008.

5.13 Determination of nitrogen leak rate

It is performed according to the provisions of the test method B - Test method of gas leak rate in GB/T 20671.4-2006. The specimen is a concentric ring which has an inner diameter of 32.3 mm ± 0.1 mm and an outer diameter of 44.3 mm ± 0.1 mm. The thickness of the specimen is the actual thickness of the product. The flange pressing force is 20 MPa ± 1 MPa. The test medium is nitrogen which has a purity of more than 99%. The medium's pressure is 0.98 MPa ± 0.02 MPa.

5.14 Oil seal test

It is performed according to GB/T 540-2008.

5.15 Determination of peelability

5.15.1 Test procedure

5.15.1.1 Cut 3 pieces of 20 mm × 100 mm specimens. The edges shall be cut neatly.

5.15.1.2 Peel off the fiber rubber layer on both sides of the conditioned sample strip. Then observe the surface of the metal core sheet after peeling off.

5.15.2 Test evaluation

If the surface of the metal core plate of the three specimens are adhered with a fiber rubber layer, the test results are reported to be acceptable, otherwise it is unqualified.

5.16 Determination of loss on ignition

Cut the 40 mm × 40 mm gasket material test piece and the corresponding metal material test piece of the same specification. Respectively measure their length, width, thickness. Weigh their mass. Calculate the density of the metal material test piece. Place the gasket material test piece in a high-temperature furnace at a predetermined test temperature for 1 hour. Take it out and cool it to room temperature. Weigh the mass. The mass difference before and after the burning of the test piece is divided by the difference of the mass of the test piece before …

5.18

Observe the remaining of the grid portion.

5.18.2 Test evaluation is in accordance with Appendix C.

5.19 Determination of coating hardness

It is performed according to GB/T 6739-2006.

5.20 Reliability test

The gasket shall be tested together with the engine for reliability, in accordance with GB/T 19055-2003.

6.1 General requirements

The gasket shall be inspected by the quality inspection department of the manufacturer in accordance with this standard and technical documents, meanwhile accompanied with a certificate of conformity.

6.2 Classification of inspections

6.2.1 Exit-factory inspection

The exit-factory inspection items are: appearance, size and deviation, density, density deviation, transverse tensile strength, compression rate, rebound rate, softness, weight gain rate after antifreeze immersion, thickening rate after antifreeze immersion, change of appearance after antifreeze immersion, peelability, adhesion, coating hardness.

6.2.2 Type inspection

The type inspection of the gasket includes all the items as specified in Chapter 4.

Type inspection shall be carried out in one of the following cases:

a) The product of trial production or first batch production;

b) After formal production, if there are major changes in structure, materials and processes, which may affect product performance;

c) During the normal production, the type inspection shall be carried out once every six months;

d) When the production is restored after suspension for more than one year;