1、 FORD LABORATORY TEST METHOD BO 001-02 Date Action Revisions 2001 03 20 Editorial no technical change A. Cockman 1992 07 13 Printed copies are uncontrolled Page 1 of 3 Copyright 2001, Ford Global Technologies, Inc. PLASTICS - TEST FOR AGING IN GASOLINE Application This test method describes the proc
2、edure for evaluating the long term effects of gasoline on the tensile strength and elongation of plastics at elevated temperatures. This test is generally intended for initial qualification of plastic materials. Scope Standard tensile test bars, prepared in accordance with ASTM D 638 are placed in a
3、 stainless steel autoclave with a slurry of activated carbon and gasoline. At specified intervals, test bars are removed and tensile tests performed. The tensile strength and percentage elongation at break are measured. Apparatus Required Autoclave Type 316 stainless steel, 2 litre capacity, with th
4、readed aperture in the head sealed by a stainless steel plug. Parr Instrument Number 4612, or equivalent. Source: Parr Instrument Co. Moline, Illinois Oven Bench model oven, gravity convection Precision-Freas Model 124A or equivalent. Source: VWR Scientific P.O. Box 187 Allen Park, Michigan 48101 Ga
5、soline ASTM Fuel “C“ shall be used for all tests unless otherwise specified in the Engineering Materials Specification. Activated Carbon ESF-M99G117 activated carbon. To be obtained from the responsible Product Engineering Office. Activated carbon to be acid free (pH 6.0 to 8.0) and dry (moisture co
6、ntent less than 0.5 %). Extra activated carbon to be stored in desiccator. FORD LABORATORY TEST METHOD BO 001-02 Page 2 of 3 Copyright 2001, Ford Global Technologies, Inc. Beaker Stainless steel, 4 litre capacity VWR Catalog No. 13977-166 or equivalent. Desiccator Cabinet or glass jar type, with des
7、iccant. Caution All operations including preparation of carbon-gasoline slurry must be carried out under an exhaust hood, with appropriate safety precautions, i.e., no smoking, open flames, etc. Lights in hood must be explosion proof type. Oven must be placed in hood at all times during aging operat
8、ion. Conditioning and Test Conditions All test values indicated herein are based on material conditioned in a controlled atmosphere of 23 +/- 2 C and 50 +/- 5 % relative humidity for not less than 24 h prior to testing and tested under the same conditions unless otherwise specified. Procedure Prepar
9、ation of Carbon - Gasoline Slurry CAUTION: Addition of gasoline causes an exothermic reaction. Add fuel slowly and stir continuously. Under exhaust hood, place approximately 2 litres of carbon in the 4 litre stainless steel beaker. Gradually add gasoline, with continuous stirring, until a slight exc
10、ess of gasoline is obtained. Proper mixture will have consistency of wet gravel. 1. Perform tensile tests according to ASTM D 638, at a testing speed (crosshead speed) of 50 mm/minute +/- 10 %, on a minimum of three dry, as molded test bars. Measure the tensile strength and elongation at break. 2. P
11、lace 35 dry as molded 3.2 by 216 mm tensile test bars in autoclave. 3. Add sufficient slurry to cover the bars. Care must be taken to assure all bars are separated by slurry. When all test bars are properly placed in the slurry, carefully add slurry to completely fill the autoclave. 4. Seal autoclav
12、e and place in upright position in oven located in exhaust hood. Oven to be operating at 120 +/- 2 C. Close oven. FORD LABORATORY TEST METHOD BO 001-02 Page 3 of 3 Copyright 2001, Ford Global Technologies, Inc. 5. Unless otherwise specified, a minimum of three test bars are to be removed and tested
13、after 2, 4, 6 and 8 weeks. Additional bars can be taken out of the autoclave and tested if necessary. To remove bars, remove autoclave from oven. Immerse the lower portion (not the head) of autoclave in cold running water for approximately 3 h. Open autoclave, remove bars, reseal autoclave and retur
14、n to oven. 6. If necessary, a small amount of gasoline can be added to the autoclave to maintain the slurry. If, upon opening, the vessel is significantly dry, leakage is indicated. The test should be discontinued if this occurs. 7. Clean the test bars by wiping with paper tissue or paper toweling.
15、Tensile tests are to be run within 24 h of removal from autoclave. Store test bars in desiccator until ready to test. 8. Perform tensile tests according to ASTM D 638, at a testing speed (cross-head speed) of 50 mm/minute +/- 10 %. Measure the tensile strength and elongation at break. 9. Report tens
16、ile strength as required in the Engineering Spoecification. Unless otherwise specified, elongation at break of less than 10 % after 8 weeks of aging indicates failure of the test. 10. Upon completion of the tensile tests on each of the three bars if one value is more than 20 % less than either of th
17、e other two, and less than the specification minimum, two additional bars shall be tested. If either of those two tests are less than the specification minimum, the material is considered to have failed the test. If two or more of the original three bars fall below the specification minimum, the mat
18、erial is considered to have failed the test. If one of the three test bars is less than the specification minimum, and less than 20 % below the other two, the material is considered to have failed the test. Chemicals, materials, parts, and equipment referenced in this document must be used and handled properly. Each party is responsible for determining proper use and handling in its facilities.
