1、GM DAEWOO Auto & Technology EDS Engineering, GM DAEWOO Auto & Technology Standards ETCHING TEST ON CARBURIZED AND/OR HEAT TREATED PARTS FOR SURFACE TEMPER INSPECTION EDS-T-7175 ISSUED DATE: 1998. 02. 28 REVISED DATE: 2006. 06. 19 VERSION: 2 EDS-T-7175ETCHING TEST ON CARBURIZED AND/OR HEAT TREATED PA
2、RTS FOR SURFACE TEMPER INSPECTION PAGE: 1/2 ISSUED DATE: 1998. 02. 28 REVISED DATE: 2006. 06. 19 VERSION: 2 GM DAEWOO Auto & Technology 1. PURPOSE This standard aims at specifying methods of inspecting the over-heated or burned-out areas of carburized or heat-treated parts during grinding by etching
3、 them. 2. TEST EQUIPMENT AND REAGENT 2.1. Tank for washing solvent (tank 1) : Trichloro ethan 2.2. Tank for etching liquid, nitric acid-alcohol (tank 2) : Mixture of max. 4% nitric acid (6971%) in volume, ethyl alcohol and methyl-alcohol (C.P.) 2.3. Tank for washing water (tank 3) : Tap water tank w
4、ith drainage 2.4. Tank for etching liquid, hydrochloric acid-water (tank 4) : Mixture of hydrochloric acid (3638%) and water (10% in volume) 2.5. Tank for washing water (tank 5) : Tap water tank with drainage 2.6. Tank for pre-inspection (tank 6) : Ethyl alcohol or methyl-alcohol (C.P.) 2.7. Inspect
5、ion : Proper ventilation and illumination 3. TEST CONDITIONS Unless specified otherwise, test samples shall be exposed to temperature of 232K and relative humidity of 505% for 24 hours at least prior to test. 4. TEST PROCEDURES 4.1. Extract oil for the parts from trichloro ethan (tank 1). (Note) Oil
6、 film shall be completely removed for uniform etching of the portion to inspect. Otherwise, visual inspection becomes impossible due to irregular etching and spots. 4.2. Under 232, dip the sample into etching liquid, nitric acid-alcohol (tank 2) for 1015 seconds or for required time. 4.3. Under 232,
7、 wash the sample with clean water in tank 3. (Note) At washing, drain shall be made at the same time and proper measures shall be provided to prevent secondary corrosion or pollution by acid. 4.4. Dip the sample into etching liquid, HCl-water (tank 4) for a required time (generally 415 seconds depen
8、ding on the parts and operator). EDS-T-7175ETCHING TEST ON CARBURIZED AND/OR HEAT TREATED PARTS FOR SURFACE TEMPER INSPECTION PAGE: 2/2 ISSUED DATE: 1998. 02. 28 REVISED DATE: 2006. 06. 19 VERSION: 2 GM DAEWOO Auto & Technology 4.5. Wash the sample with clean water in tank 5. (Note) At washing, drai
9、n shall be made at the same time and proper measures shall be provided to prevent pollution by acid as well as dilution by alcohol washing. 4.6. Under 232, wash the sample with alcohol (tank 6). 5. EVALUATION After blowing with dry air, inspect the part surface for uniform corrosion and resulting co
10、lor change to gray. If tempered or burned, spots or isolated bright or dark areas are present on the surface. Acceptance or rejection of the part is based on the approved visual inspection standard. 5.1. Handling of solution Solution shall be replaced once used. 6. REFERENCE Ford laboratory test method BA 156-01: etching test on carburized and/or heat treated parts for surface temper inspection
