1、DEUTSCHE NORM Auaust 1996 Determination of shear stability of polymer-containing lubricating oils by the Shell four-ball tester DIN 51 350-6 - ICs 75.100 Descriptors: Lubricants, polymer-containing lubricating oils, testing, shear stability. Prfung von Schmierstoffen - Prfung im Shell-Vierkugel-Appa
2、rat -Teil 6: Bestimmung der Scherstabilitt von polymerhaltigen Schmierlen In keeping with current practice in standards published by the International Organization for Standardization (ISO), a comma has been used throughout as the decimal marker. Foreword This standard has been prepared by Technical
3、 Committee 661 Prfung von Schmierlen, sonstigen len und Paraffinen of the Fachausschu Minerall- und Brennstoffnormung of the Normenausschu Materialprfung (Materials Testing Standards Committee). 1 Scope and field of application The method specified in this standard serves to determine the shear stab
4、ility of polymer-containing lubri- cating oils, including pressure fluids, using the Shell four-ball tester as specified in DIN 51350-1 and a tapered roller bearing. The test results make it possible to predict the in-service permanent viscosity loss. 2 Normative references This standard incorporate
5、s, by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the titles of the publications are listed below. For dated references, subsequent amendments to or revisions of any of these publications apply to this
6、 standard only when incorporated in it by amendment or revision. For undated references, the latest edition of the publication referred to applies. DIN 51 350-1 DIN 51 562-1 DIN 51631 Testing of lubricants by the Shell four-ball tester - General principles Determination of kinematic viscosity using
7、the standard design Ubbelohde viscometer Special boiling point spirits - Requirements 3 Concept The measure of shear stability used in this standard is the percentage viscosity loss, R, calculated using the following equation: where vo is the kinematic viscosity of the unsheared oil, in mm/s; Y, is
8、the kinematic viscosity of the sheared oil, in mm/s. NOTE: A small value is indicative of a high shear stability. Continued on pages 2 to 4 Translation by DI N-Sprachendienst. In case of doubt, the German-language original should be consulted as the authoritative text. No pari of this translation ma
9、y be reproduced without the prior permission of Ref. No. DIN 51 350-6 : 1996-0 V Deutsches Institut fr Nonung e. V., Berlin. Luth Verlag GmbH, D-10772 Berlin, has the exclusive right of sale for German Standards (DIN-Normen). English price group 05 Sales No. 0105 06.98 Page 2 DIN 51 350-6 : 1996-08
10、16 Countersunk head screw Measuring arm Lubricating oil O-ring O-ring 6 Cone 7 Shaft insert 8 Cheese head screw 9 Spring lock washer 10 Seating of cone 11 Locknut 13 Heater 14 Locating hole for screwed-in socket 15 Housing 16 Parallel pin 17 Cone point 12 cup Figure 1: Shear stability testing appara
11、tus 4 Principle Using the splash lubrication method, 40 ml of the lubricating oil is tested at a constant temperature of 60 “C in a tapered roller bearing driven by the Shell four-ball tester. The test is carried out at constant speed and the load applied during a given running time is 5000 N. The k
12、inematic viscosity of the lubricating oil is determined as specified in DIN 51562-1 at a temperature of 1 O0 “C before and after the test. 5 Designation Designation of the method of determining the shear stability of polymer-containing lubricating oils using the Shell four-ball tester and a tapered
13、roller bearing (KRL), with test duration A: Test method DIN 51350-06 - KRUA 6 Apparatus 6.1 Shell four-ball tester, as specified in DIN 51 350-1. 6.2 Tapered roller bearing, of type 32008X1). 6.3 Tapered roller bearing holder), as shown in figure 1. I) Information on sources of supply is obtainable
14、from DIN-Bezugsquellen fr normgerechte Erzeugnisse im DIN Deutsches Institut fr Normung e.V., Burggrafenstrae 6, D-10787 Berlin. Page 3 DIN 51 350-6 : 1996-08 6.4 using a thermostat provided with external control. 6.5 Ubbelohde viscometer. Temperature control device, for heating the tapered roller b
15、earing holderto a temperature of (60 k 1) “C, 7 Preparation 7.1 Prior to the test, clean the holder and the tapered roller bearing, using a suitable solvent (e.g. DIN 51 631 -2-A special boiling point spirit), and dry them. Preparing the tapered roller bearing holder 7.2 Assembly of tapered roller b
16、earing holder 7.2.1 Fit the cup of the tapered roller bearing (12) in the cleaned housing (15) and fill in (40 k 0,2) ml of the lubricating oil (3) to be tested. 7.2.2 Place the cleaned cone (6) in the seating (1 O). 7.2.3 Fit the cone, together with the rolling elements, in the housing prepared as
17、specified in subclause 7.2.1 and secure using the locknut. 7.2.4 Using the shaft insert (7), place the tapered roller bearing holder so prepared into the Shell four-ball tester and apply a load of 5000 N. 7.2.5 Connect the temperature probe and temperature control and check their function. 7.3 Test
18、conditions See table 1. Table 1: Test conditions I About 1450 min- Rotational speed of motor I I Lubricating oil temperature I (6Okl)“C I Lubricating oil test volume I (40 k 0,2) ml I I I Test load I 5000 N I Test duration A I About 4 h, equivalent to 348000 revolutions I I Test duration B I About 8
19、 h, equivalent to 696000 revolutions I Test duration C I About 20 h, equivalent to 1740000 revolutions NOTE: For induction motors, the specification of the tyst duration or the number of revolutions of the motor is based on a nominal rotational speed of 1 450 min- . When testing at other speeds, the
20、 test duration is to be corrected accordingly. 8 Procedure 8.1 After the check specified in subclause 7.2.5, heat the tapered roller bearing holder to about 50 “C with the motor stopped. 8.2 Once the temperature specified in subclause 8.1 has been reached, set the temperature control to (60 k 1) “C
21、and start the motor. 8.3 The test run shall be finished at the end of the given test duration (see table 1). 8.4 Determine the kinematic viscosity of the lubricating oil at 1 O0 “C as specified in DIN 51 562-1 before and after shearing. Calculate the percentage viscosity loss, R, as described in cla
22、use 3. 9 Expression of results Refer to this standard when reporting the result of viscosity loss as specified in subclause 8.4 and round the result to the last significant decimal place. Page 4 DIN 51 350-6 : 1996-08 EXAMPLES: Using a tapered roller bearing (KRL), the percentage viscosity loss afte
23、r a test run of four hours (A), equivalent to 348 O00 revolutions of the motor, is 10,06 YO. Using a tapered roller bearing (KRL), the percentage viscosity loss after a test run of 20 hours (C), equivalent to 1740000 revolutions of the motor, is 29,55 %. DIN 51350-06 - KRUA: 10,l % DIN 51350-06 - KR
24、UC: 29,6 % 10 Precision Use the following criteria to assess the precision of results. 10.1 Repeatability limit The difference between two successive results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run,
25、with a normal and correct use of the test method, exceed the value of 1 ,O only in one case in twenty. 10.2 Reproducibility limit The difference between two single and independent results, obtained by different operators working in different laboratories on identical test material would, in the long
26、 run, with a normal and correct use of the test method, exceed the value of 5 YO only in one case in twenty. 11 Test report The test report shall contain at least the following information: a) a reference to this standard; b) type and designation of the product tested; c) expression of results as specified in clause 9; d) any deviation, whether agreed or not, from this method; e) date of testing.
