SAE J20:2022 pdf download

SAE J20:2022 pdf download Coolant System Hoses
5.1.2 Cold Flexibility The following procedure shall be used: For hose 25.4 mm ID and smaller, specimen shall consist of a complete hose of length sufficient to perform bend test described as follows: the hose shall be placed in a cold box for 5 hours at the temperature specified in Table 1. The hose shall then be flexed in the cold chamber through 180 degrees from the centerline to a diameter of 10 times the maximum outside diameter of the hose within 4 seconds. The hose shall not fracture and shall not show any cracks or breaks in the tube or cover.
For hose larger than 25.4 mm ID, specimens are to be 25.4 mm long sections of the complete hose. The specimen and test fixture shall be placed in a cold box for 5 hours at the temperature specified in Table 1. The specimen is then compressed to 50% of its original inside diameter between parallel plates within 4 seconds. The specimen shall not crack or break. The testing fixture shall be in the cold box during the entire test.
NOTE: For LT hose, see Section 13 for specific cold flexibility requirements.
5.1.3 Ozone Test and Requirements
The following test and requirements apply:
When applicable, use test procedure ASTM D1149.
For hose 25.4 mm ID and smaller, a specimen of hose of sufficient length shall be bent around a mandrel with an outside diameter equal to eight times the specified OD of the sample. The two ends shall be tied at their crossing with enameled copper or aluminum wire. After mounting, the specimen shall be allowed to rest in an ozone-free atmosphere for 24 hours at standard laboratory test temperature.
The mounted specimen shall be placed in a test chamber containing ozone at a partial pressure of 50 mPa ± 5 mPa at a temperature of 40 °C ± 1 °C. After 100 hours of exposure, the specimen shall be removed and allowed to cool to standard laboratory test temperature and then be inspected visually under 7X magnification. The sample must not show any cracks except for the area immediately adjacent to the wire, which shall be ignored. For hose larger than 25.4 mm ID, prepare a specimen by cutting a strip of the whole hose 12.7 x 100 mm and tie specimen (cover out) around a 12.7 mm diameter mandrel. Condition in the same manner as specified previously for the whole hose and apply the same conditions and requirements. This test applies to the cover only and cracks in the exposed tube or cut edges of the cover shall be ignored.