New Item API Standard 6A718 Proposed New Macro Etchant Paul Maxwell 30 June 2011

1. New ItemAPI Standard 6A718Proposed New Macro EtchantPaul Maxwell30 June 2011

2. Stated Goal: • Add “Dilute Aqua Regia-Heated” Etchant as an approved etchant for the requirements stated in API Standard 6A718(Sec. 4.2.1.1) • Current Macro Etchants • Option A: Canada’s Etchant 100 ml H2SO4,100ml HF, 50ml HNO3, 400 ml H2O, Etch at 160°F to 180°F (71°C to 82°C) • Option B: Aqua Regia 200 ml HCl, 100 ml HNO3 • Option C: Kalling’s No. 2 200 ml Methanol, 200 ml HCl, 10 g CuCl2 • Option D: Hydrochloric-Peroxide H2O2 (30 %) 100 ml, HCl 200 ml, H2O 300 ml, Remove stains with 50 % HNO3

3. Materials: Alloy 718 Order/Heats utilized in the evaluation: 4 orders/heats & associated locations were evaluated for each etchant W77942/600409 – 1A,1X See photos 1(API 6A718 Option B etch) & 2 (“Dilute Aqua Regia-Heated” etch) W79943/600382 – 1A, 1X See photos 3(API 6A718 Option B etch) & 4 (“Dilute Aqua Regia-Heated” etch). W79939/600409 – 2A, 2X See photos 5(API 6A718 Option B etch) & 6 (“Dilute Aqua Regia-Heated” etch). W74406/600274 – 3A, 3CO See photos 7(API 6A718 Option B etch) & 8 (“Dilute Aqua Regia-Heated” etch)

4. Materials (Continued) Etchants Utilized: Specified - API 6A718 Option B Etchant - Aqua Regia: 200 ml HCL, 100 ml HNO3. Unheated - Room Temp (72F/23C). Proposed - “Dilute Aqua Regia-Heated” Etchant: Aqua Regia, 250 ml HCL, 10- 20 ml HNO3 Processing Temp - 140F – 165F.

5. Test Methodology • Same orders/heats, locations, and disc specimens utilized. • Prep the surface of the specimens prior to etching process. • Etch the specimensutilizing either the API 6A718 Option B etchant or the “Dilute Aqua Regia-Heated” etchant. • API 6A718 Option B etchant will be unheated (room temp - 72F/23C). • “Dilute Aqua Regia-Heated” etchant will be heated to 40F to165F. • Specimen etching time will be approximately 25 to 30 minutes for each etchant type. • Specimens will be rinsed and air dried. • Inspect specimen surface to determine if the visual results are similar.

6. Results: • Specimens for all four orders/heats reveal same macrostructure results. • See attached photos regarding visual comparison.

7. Summary: • Specimens from four Alloy 718 orders/heats and locations were processed utilizing the API 6A718 Option B etchant and the “Dilute Aqua Regia-Heated” etchant. • The etchant composition and etching temperature were the only process variables that were changed. • Visual inspection of the specimens revealed same macrostructure results (see photos). • Benefits of utilizing the “Dilute Aqua Regia-Heated” etchant include, but are not necessarily limited to, longer time period prior to burning of surface and better repeatability. • As a result of the items mentioned above, Carpenter is proposing to have the “Dilute Aqua Regia-Heated” etchant balloted as an approved etchant for the requirements stated in API Standard 6A718, Section 4.2.1.1.

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