1、 FORD LABORATORY TEST METHOD EU-BA 051-01 Date Action Revisions 2000 08 30 Revised Editorial no technical change A. Cockman 2000 05 22 Editorial no technical change A. Cockman 1994 02 28 Printed copies are uncontrolled Page 1 of 4 Copyright 2000, Ford Global Technologies, Inc. NON-METALLIC INCLUSION
2、 COUNT - THROUGH HARDENED ROLLER AND BALL BEARING STEELS Application This method is applied to through hardened steels used in the manufacture of roller and ball bearings in order to evaluate the purity grade of the steel. A non - m etallic inclusion rating number will be obtained which can be compa
3、red with requirements specified for the steel. Apparatus Required Cutting, Grinding and Polishing Equipment For micro - specimens. Microscope With a magnification of X100. Hydrochloric Acid 50 %, hot Inclusion Classification Chart (based on Kugelfischer Co., chart) See Appendix A. Full charts availa
4、ble from P.D.G. Material Laboratory. Conditioning and Test Conditions All test values indicated herein are based on material conditioned i n 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 ot
5、herwise specified. Sampling and Preparation of Samples 1. At least 5 different items shall be sampled from any one consignment. If the rating number obtained from the test is so close to the maximum requirement specified to give a doubt regarding rejection of the consignment a further 5 items must b
6、e examined in order to confirm or deny the re jection. FORD LABORATORY TEST METHOD EU-BA 051-01 Page 2 of 4 Copyright 2000, Ford Global Technologies , Inc. 2. The parts to be tested shall be cut in the hardened condition and in the exact plane of the rolling direction. For inner and outer rings and
7、rollers the longitudinal axis of the part can be seen to be the rolling direction but for the balls the poles will need to be revealed by a minimum etching time in hot hydrochloric acid (50 %) and the balls cut in the plane of the poles. 3. The items to be examined shall be cut in the longitudinal d
8、irection and the whole cut surface shall be prepared an d examined. 4. The grinding and polishing must be carefully carried out to obtain a high quality surface preparation with the inclusions retained intact. Light etching and repolishing is allowable in the final stages of preparation but the surf
9、ace must be evaluated in the unetched condition. Procedure 1. The complete surface area of each section is examined under a microscope at X100 magnification and a field of view of 75 +/ - 5 mm. Each field of view shall be examined and the worst of each type of inc lusion, as shown on classification
10、chart, shall be recorded (see Appendix A). 2. For vacuum melted steels inclusions corresponding to Rating Numbers 1/4 to 6 must be noted. 3. For non - vacuum melted steels only the Rating Numbers from 3 to 6 should be use d unless the steel has a large number of the very small inclusions. 4. The tot
11、al number for each size of each type of inclusion in all the prepared surfaces of all the items is then added together to give the totals. Evaluation The total surface area ex amined is also calculated and this is related to the standard unit surface area of 300 mm 2 . Thus the number of each size o
12、f each type of inclusion is calculated per unit area of 300 mm 2 . These numbers are then multiplied by the relevant severity factors given in Table 1 and the numbers obtained totaled for all types and sizes of inclusions to give the “Inclusion Count Number“ (see Appendix B). Chemicals, materials, p
13、arts, 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. FORD LABORATORY TEST METHOD EU-BA 051-01 Page 3 of 4 Copyright 2000, Ford Global Technologies , Inc. NON-METALLIC INCLUSION COUNT -
14、THROUGH HARDENED ROLLER AND BALL BEARING STEELS TABLE 1 Severity Factors Inclusion Number (from comparison chart) Sulphide Type A S Alumina & Silicate Types AO & SO Oxide Types KO & VO 1/4 1/2 1 2 3 4 5 6 0.15 0.3 0.6 1.6 5 15 40 100 0.3 0.6 1.6 5 15 40 100 250 0.25 0.5 1.3 4.2 11 26 65 150 FORD LABORATORY TEST METHOD EU-BA 051-01 Page 4 of 4 Copyright 2000, Ford Global Technologies , Inc.
