1、 FORD LABORATORY TEST METHOD EU-BA 051-02 Date Action Revisions 2001 03 02 Revised Editorial no technical change A.Cockman 1994 02 28 Printed copies are uncontrolled Page 1 of 4 Copyright 2001, Ford Global Technologies, Inc. NON-METALLIC INCLUSION COUNT SPRINGS Application This method is applied to
2、hardened and tempered spring steel used in the manufacture of springs in order to evaluate the purity of the steel. A non-metallic inclusion rating will be obtained based on the modified Jernkontoret (J.K.) chart as described in Method A, ASTM E 45-63 (69). Apparatus Required Cutting, Grinding and P
3、olishing Equipment For taking and preparing microspecimens. Microscope With a magnification of X100. Inclusion Classification Chart ASTM E 45, Plate 1 Sampling Coil and Single Leaf Springs One item will be selected at random to represent the consignment. Multi-Leaf Springs One assembly will be selec
4、ted at random to represent the consignment. Each leaf in that assembly will then constitute a single separate sample that has to be evaluated. Coil Springs The specimen used for microscopical evaluation shall be a longitudinal section cut from the sample as shown: FORD LABORATORY TEST METHOD EU-BA 0
5、51-02 Page 2 of 4 Copyright 2001, Ford Global Technologies, Inc. Coil Springs Leaf Springs The section shall be taken at a position approximately midway between the centre of a leaf and one of its ends. Care shall be taken that the sections are cut at right angles to the relevant faces and sides. Th
6、e whole longitudinal surface ABCD shall be prepared for microscopical examination. 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
7、 tested under the same conditions unless otherwise specified. Preparation The grinding and polishing must be carefully carried out to obtain a high quality surface preparation with the inclusions retained intact and not pitted, dragged or obscured. Light etching and repolishing is allowable in the f
8、inal stages of preparation but the surface must be evaluated in the unetched condition. FORD LABORATORY TEST METHOD EU-BA 051-02 Page 3 of 4 Copyright 2001, Ford Global Technologies, Inc. Procedure The complete surface area of each section is examined under a microscope at a magnification of X100 wi
9、th a field of view diameter of approx 80 mm. Each field of view on the sample is compared with the fields of view shown in Plate 1, ASTM E 45-63. Each type of inclusion in each field must be compared with the same type of inclusion shown in Plate 1 and, if its size is equal to or greater than the fi
10、eld marked 1, the field judged to be nearest to that being evaluated is recorded in both the thin and heavy series. If a field is judged to halfway between two numbers it is permissible to record it to the nearest half number, e.g. half way between 2 and 3 is recorded as 2 1/2. Each inclusion type (
11、A, B, C and D) is evaluated and recorded for each field. The results of surveying the complete area of the microsection are reviewed and the largest number, i.e. the largest size for each inclusion type in both thin and heavy series is found. These numbers are then called the “worst field“ figures f
12、or each inclusion type in that microsection. If any of these numbers is greater than that specified for that type of inclusion (i.e. A, B, C or D) or series (i.e. thin or heavy), then that microsection constitutes a failure to pass the specification. Also, if more than 20 % of the field of views con
13、tain inclusions equal in size to the maximum specified for that particular type of inclusion this also constitutes a failure to pass the specification. Resampling In the event of the microspecimen failing to pass the requirements of the specification, this shall not constitute a failure of the consi
14、gnment. The decision will be delayed until more samples have been evaluated as detailed below: Item(s) Already Evaluated Two more microspecimens shall be taken as described above and from such a position on the coil or leaf that the 3 microsections are from the ends and middle of a length and coveri
15、ng at least 75 % of the length of that spring. Extra Items or Assemblies Two more coil springs or leaf spring assemblies shall be chosen at random from the consignment. 3 microsections shall be taken from each of these coils or each individual leaf from each of these assemblies, as detailed above, f
16、rom positions to represent the middle and two ends of the coil or leaf. All these microsections will be evaluated as for the first microsections and the worst field numbers found for each item. FORD LABORATORY TEST METHOD EU-BA 051-02 Page 4 of 4 Copyright 2001, Ford Global Technologies, Inc. These
17、worst field numbers will be averaged. For coil and single leaf springs there will be 9 sets of results to average. For multi-leaf spring assemblies there will be 3 times x sets of results to average where x equals the number of leaves in an assembly. An example of the averaging of 9 sets of results
18、is shown in Table 1, ASTM E 45-63 (69). If any of these averaged results for any type or series of inclusion is greater than 75 % of the figure specified, the consignment has failed to pass the specification. Also, if more than 20 % of the fields of view examined in the total number of microsections
19、 taken have inclusions equal to or greater than that specified for that particular type of inclusion this also constitutes a failure to pass the specification. 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.
