1、 FORD LABORATORY TEST METHODBJ 154-01Date Action Revisions 2007 06 07 Activated L. Rodrigues Printed copies are uncontrolled Copyright 2007, Ford Global Technologies, LLC Page 1 of 2 TEST METHOD FOR DETERMINATION OF LUBRICANTS SPECIFIC GRAVITY (CUP METHOD) Application This method is for the determin
2、ation of the Specific Gravity (SG) of grease. This method is based on GKN 311450 and adopted by Ford in Brazil. Definition Specific Gravity (relative density) of grease is defined as the ratio of a given volume of grease at a given temperature to the mass of an equal volume of water at the same temp
3、erature. Apparatus Required Specific Gravity (SG) Cup and Lid conforming to the dimensions given in figure 1. It can be manufactured from aluminium or stainless steel. Spatula, with flat sufficient to level off the grease in the cup. Top Pan Balance (4 figure, capacity 200g). FORD LABORATORY TEST ME
4、THODBJ 154-01Printed copies are uncontrolled Copyright 2007, Ford Global Technologies, LLC Page 2 of 2 Procedure The test should be performed at 20 C if working to set parameters, otherwise a temperature of 15 C to 30 C is acceptable. Weight the SG cup and record the result (A). Using a spatula, cha
5、rge the SG cup with the test grease, periodically jarring the cup in order to drive out trapped air. Overfill the cup slightly and scrape off the excess grease extending above the rim by drawing the blade of the spatula across it. Place the lid onto the cup and gently push down, thus forcing excess
6、grease out of the side of the cup and through the hole in the lid. Ensure all excess grease has escaped, then wipe clean. Weigh the SG cup + grease (B). Calculation: Apply the following calculation to determine the SG of the test grease: SG of test grease = Weight of grease (B A) x Cup Constant Note
7、 For this method a cup constant must be calculated. This is done by first determining the weight of water (with known SG) required to fill the cup and by then applying the following: SG Water Cup Constant x 100 Wt. Water Expression of Results Two determinations should be carried out in order to obt
8、ain an average result. The result should be considered suspect if the difference between two determinations 0.5%. Report results to two decimal places. Precision and Bias: At this time the precision of the method has not been established. Note: This method does not take into account the air buoyancy correction which for an SG of 0.90 is 0.00012 and can therefore be considered negligible.
