1、 FORD LABORATORY TEST METHOD BA 156-01 Date Action Revisions 2001 03 02 Revised Editorial no technical change A. Cockman 1992 04 07 Printed copies are uncontrolled Page 1 of 3 Copyright 2001, Ford Global Technologies, Inc. ETCHING TEST ON CARBURIZED AND/OR HEAT TREATED PARTS FOR SURFACE TEMPER INSPE
2、CTION Application This method is used for etching carburized and/or heat treated parts to reveal areas which have been overheated or burned during grinding operations. Apparatus and Chemicals Required Cleaning Solvent Tank Tank No. 1 Trichlorethane Etchant Solution Tank, Nitric Acid-Alcohol Tank No.
3、 2 A mixture of 4 % max by volume of 69 - 71 % Nitric Acid and ethyl and methyl alcohol (c.p.) Water Rinse Tank Tank No. 3 Running water with overflow provisions. Etchant Solution Tank, HCl-Water Tank No. 4 A mixture of 10 % by volume of Reagent Grade hydrochloric acid (36 - 38 %) and water. Water R
4、inse Tank Tank No. 5 Running water with overflow provisions. Pre-Inspection Tank Tank No. 6 Ethyl or methyl alcohol (c.p.) Inspection Station With suitable dry air blow-off and adequate lighting. Rust Protection Tank Tank No. 7 FORD LABORATORY TEST METHOD BA 156-01 Page 2 of 3 Copyright 2001, Ford G
5、lobal Technologies, Inc. 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 tested under the same conditions unless otherwise specifi
6、ed. Procedure 1. Degrease part in Trichlorethane, Tank No. 1. Note: Care should be taken that the oil film is completely removed so that a uniform etch is obtained on the piece being inspected. Otherwise, staining and non-uniform etch pattern will interfere with the visual inspection disposition. 2.
7、 Immerse in the etchant solution, Nitric Acid-Alcohol, Tank No. 2, at 23 +/-2 C for 10 - 15 seconds, or as required. 3. Rinse in clear water at 23 +/- 2 C, Tank No. 3. Note: Overflow water rinse must be provided and precautions must be taken to prevent acid contamination of the second etch process.
8、4. Immerse in the etchant solution, HCl-Water, Tank No. 4, as necessary (generally 4 - 15 seconds depending upon part and operator). 5. Rinse in clear water, Tank No. 5. Note: Overflow water rinse must be provided and precautions must be taken to prevent acid contamination and dilution of the alcoho
9、l rinse. 6. Rinse in Alcohol at 23 +/- 2 C, Tank No. 6. FORD LABORATORY TEST METHOD BA 156-01 Page 3 of 3 Copyright 2001, Ford Global Technologies, Inc. Evaluation Blow off with dry air and examine ground surfaces of part for uniformity of gray color produced by etching. Tempering or burning, if pre
10、sent, will be evident by a mottled surface or isolated dark and light areas. Acceptance or rejection shall be based on visual acceptance standards as approved by Product Engineering. Rust Preventative Treatment Dip in the corrosion preventative oil UMC 007-8002, Castrol Dewatering 904, or equivalent
11、. Note: For effective rust protection, it is very important to maintain the material concentration and avoid solution contamination. Solution Control All solutions must be changed at start of shift and at mid-shift when etch station is in operation. 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.
