1、 FORD LABORATORY TEST METHOD EU-BA 014-02 Date Action Revisions 2000 08 22 Revised Editorial no technical change A. Cockman 2000 05 22 Editorial no technical change A. Cockman 1993 12 31 Printed copies are uncontrolled Page 1 of 2 Copyright 2000, Ford Global Technologies, Inc. CONTROL OF NODULARITY
2、IN NODULAR IRON CASTINGS BY USE OF SOUND VELOCITY TEST EQUIPMENT Scope This method is used to ensure that the desired (specified) degree of nodularity is maintained on production parts which require 100 % testing for nodularity. Apparatus Required Cut Off Machine Grinding and Polishing Equipment Met
3、allurgical Microscope Ultrasonic Equipment With capability of measuring sound velocity and necessary probes. Tanks and Fixtures To allow the immersion technique to be employed. Conditioning and Test Conditions All test values indicated herein are based on material conditioned in a controlled atmosph
4、ere of 23 +/ - 2 C and 50 +/ - 5 % relative humidity for not less than 24 h prior to testing and tested under the same conditions unle ss otherwise specified. Procedure 1. Surveillance of Casting Process (metallographic) Nodularity to be determined metallographically in line with FLTM CA 2 - 1. Meta
5、llographic specimens to be prepared from special test pieces cast on the product molding line. Test piece to be cast with the last casting from the ladle. Minimum specified nodularity must be achieved. Frequency of test is dependent on actual process and foundry concerned. This will be agreed betwee
6、n Ford Q.C. (SQA and Chem & Met) and aff ected vendor foundry, and once agreed must not be changed without written concurrence. After Ferritising Heat Treatment FORD LABORATORY TEST METHOD EU-BA 014-02 Page 2 of 2 Copyright 2000, Ford Global Technologies, Inc. Determination of Sound Velocity in Each
7、 Casting 1. In order to assure that all cast and heat treated components have a satisfactory n odularity in line with the metallographic test samples 100 % nondestructive testing by ultrasonic velocity measurement is necessary. Immersion techniques are recommended as they eliminate problems arising
8、from probe to specimen contact. Test equipment t o be approved by Ford Q.C. (SQA and Chem & Met) and must not be changed without written concurrence. Calibration of test equipment - for details see Laboratory Test Instruction Sheet. Calibration and control of the ultra - sonic test equipment has to
9、be p erformed with special test samples. Test samples are as follows: (A) Standard sample - STEEL Verified by manufacturer of equipment and/or national institutes) (B) Component, In which the spheroidal size, - type, - percentage and the matrix are in accord ance to the engineering specification. (C
10、) Negative - Component (not OK) for functional checking of the ultrasonic test equipment. The sound velocity range in nodular cast iron based on present experience is between 5550 and 5750 m/s, whereas the sound vel ocity figure in steel is constant 5920 m/s. In order to optimize the confidence leve
11、l of the sound velocity measurement an empirical determination of the typical sound velocity data of the respective casting quality and the required minimum percentage of nodularity is necessary. 2. Experience has shown that nodularity is not uniform throughout the casting. If it is not feasible to
12、check at the point of minimum nodularity, then a checking position must be selected where the nodularity is known to have a definite ratio to that at the position of minimum nodularity. For acceptance checking the percentage nodularity in that selected position must be increased by that ratio. e.g.
13、Assume: Min nodularity is 80 %, and that when it occurs, the nodularity in th e acceptance checking position is 90 %, then all results in the acceptance checking position must be multiplied by 80/90 to obtain nodularity at position of minimum nodularity. 3. Identification All castings, bought off OK
14、 after ultrasonic testing must be identified by a durable identification in a non -stressed area. PDG to indicate suitable positions (note identification must be such that it will be present throughout the life of the component). 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.
