Thermal Spray Aluminum for Aluminum Corrosion Prevention

Transcription

1 Thermal Spray Aluminum for Aluminum Corrosion Prevention Planning, Production Processes and Facilities Panel Project 22 August 2017

2 Agenda Problem Overview Project Overview Project Activities vs. Work Breakdown Structure (WBS) Next Steps Questions 2

3 Problem Overview Aluminum is part of the Navy s $3B ship corrosion problem Mg-Al 5000 series (5086, 5083, 5059, 5456) alloys will sensitize over time, which becomes exfoliation or worse, stress corrosion cracking (SCC) Sensitization and SCC are already a huge repair problems on CG 47 superstructure, and are already emerging on LCS 50% of USN ships under contract or construction use aluminum significantly LCS, LHA, JHSV, SSC, CVN It s not limited to an in-service repair problem Aside from Low Solar Absorption (LSA) paint, there is no preventative treatment for 5xxx alloys short of replacement! 3

4 Project Overview National Shipbuilding Research Program (NSRP) Planning, Production Processes and Facilities (PPPF) Panel Project Mr. Ken Fast, PPPF Chair Scope / Statement of Work This project will evaluate the use of thermal spray commercially pure (CP) aluminum (Al) coatings as an effective preventative measure for SCC in Al ship structures. Potential application scenarios, technical performance data, cost information, and a roadmap for implementation will be generated. Period of Performance: 1 Jan Jun 2017 $149,986 total funding 4

5 Project Overview Project Team Concurrent Technologies Corporation (CTC) PI and PM Huntington Ingalls Industries Newport News Shipbuilding (NNS) Fincantieri Marinette Marine Corporation (MMC) General Dynamics Bath Iron Works (BIW) Ingalls Shipbuilding Naval Surface Warfare Center Carderock Division (NSWCCD) Naval Sea Systems Command (NAVSEA) 05P NAVSEA 21 NSRP PPPF Panel NSRP Surface Preparation and Coatings (SPC) Panel SCRA Prime contractor for NSRP 5

6 Project Activities vs. WBS Task 4 Conduct Testing Conduct testing to quantify performance of thermal spray CP Al (with and without LSA paint) as preventative for SCC Testing completed Coating Quality Distortion Adhesion Bends Nitric Acid Mass Loss Test Adhesion (PATTI) Pull-Offs Corrosion (ASTM B117; scribed and unscribed) Alternate Immersion SCC Drafted and submitted Final Report / Test Report (D) 6

7 Task 4 Coating Quality Flame spray coated 5456 panels, painted (left) and unpainted (right) HVOF coated 5456 panels, painted (left) and unpainted (right) Wire arc coated 5456 panels, painted (left) and unpainted (right) 7

8 Task 4 Quality Coating Thickness Test Type Material Size Process Coating Panel ID Bends "x12" Bends "x12" Wire Arc HVOF Flame Spray Wire Arc HVOF Flame Spray TS only TS and LSA TS only TS and LSA TS only TS and LSA TS only TS and LSA TS only TS and LSA TS only TS and LSA As-received Panel Dimension (in) As Sprayed Panel Dimension (in) Calculated Coating Thickness (in) M1-WA-TS-B M1-WA-TS-B M1-WA-TS-B M1-WA-TSP-B M1-WA-TSP-B M1-WA-TSP-B M1-HV-TS-B M1-HV-TS-B M1-HV-TS-B M1-HV-TSP-B M1-HV-TSP-B M1-HV-TSP-B M1-FS-TS-B M1-FS-TS-B M1-FS-TS-B M1-FS-TSP-B M1-FS-TSP-B M1-FS-TSP-B M2-WA-TS-B M2-WA-TS-B M2-WA-TS-B M2-WA-TSP-B M2-WA-TSP-B M2-WA-TSP-B M2-HV-TS-B M2-HV-TS-B M2-HV-TS-B M2-HV-TSP-B M2-HV-TSP-B M2-HV-TSP-B M2-FS-TS-B M2-FS-TS-B M2-FS-TS-B M2-FS-TSP-B M2-FS-TSP-B M2-FS-TSP-B Generally between and

9 Task 4 Adhesion Three Point Bend Test Rig 9

10 Task 4 Adhesion 3 Point Bends (cont d.) Flame Spray CP Al on 5456 note failure of thermal spray from substrate Flame Spray CP Al on

11 Task 4 Adhesion 3 Point Bends (cont d.) Flame Spray CP Al / LSA on 5456 note failure of thermal spray from substrate, not paint from thermal spray Flame Spray CP Al / LSA on 5083 note failure of thermal spray from substrate, not paint from thermal spray 11

12 Task 4 Adhesion Bends (cont d.) HVOF CP Al on 5456 note failure of thermal spray from substrate HVOF CP Al on

13 Task 4 Adhesion Bends (cont d.) HVOF CP Al / LSA on 5456 HVOF CP Al / LSA on

14 Task 4 Adhesion Bends (cont d.) Wire Arc CP Al on 5456 Wire Arc CP Al on

15 Task 4 Adhesion Bends (cont d.) Wire Arc CP Al on 5456 Wire Arc CP Al / LSA on

16 Task 4 Adhesion (PATTI) Pull-Off Results HVOF best Wire arc 2 nd best Flame spray good For comparison, tested baseline (Al panels with primer only) PATTI failures at 400 psi, with 100% adhesive failure of primer to Al substrate 16

17 Task 4 Corrosion Testing (Neutral Salt Spray) Wire Arc CP Al on 5456 after 500 hours NSS Unpainted (top left), unpainted and scribed (top right), painted (bottom left), painted and scribed (bottom right) Results: no corrosion, no scribe undercut 17

18 Task 4 Corrosion Testing (Neutral Salt Spray) HVOF CP Al on 5456 after 500 hours NSS Unpainted (top left), unpainted and scribed (top right), painted (bottom left), painted and scribed (bottom right) Results: corrosion on unpainted panels, no scribe undercut 18

19 Task 4 Corrosion Testing (Neutral Salt Spray) Flame spray CP Al on 5456 after 500 hours NSS Unpainted (top left), unpainted and scribed (top right), painted (bottom left), painted and scribed (bottom right) Results: corrosion on unpainted panels, no scribe undercut 19

20 Task 4 Corrosion Testing (Neutral Salt Spray) Wire arc CP Al on 5083 after 500 hours NSS Unpainted (top left), unpainted and scribed (top right), painted (bottom left), painted and scribed (bottom right) Results: no corrosion, no scribe undercut 20

21 Task 4 Corrosion Testing (Neutral Salt Spray) HVOF CP Al on 5083 after 500 hours NSS Unpainted (top left), unpainted and scribed (top right), painted (bottom left), painted and scribed (bottom right) Results: corrosion on unpainted panels, no scribe undercut 21

22 Task 4 Corrosion Testing (Neutral Salt Spray) Flame spray CP Al on 5083 after 500 hours NSS Unpainted (top left), unpainted and scribed (top right), painted (bottom left), painted and scribed (bottom right) Results: corrosion on unpainted panels, no scribe undercut 22

23 Task 4 Testing Conclusions All TS panels meet Quality (per Visual Inspection) requirements Coating thicknesses generally the same Minimal distortion imparted by all processes (±0.030 at the worst) Wire arc exhibited best bend adhesion Sensitization was not significantly changed (increased OR decreased) by application of either of the three thermal spray processes HVOF performed best in pull-off adhesion testing Wire arc also performed well Wire arc performed best in NSS corrosion testing None of the specimens failed SCC testing 23

24 Task 4 Conduct Testing Conclusions PROCESS CAPABILITY AVAILABILITY APPLICABILITY QUALITY DISTORTION ADHESION - BENDS ADHESION - PULL-OFFS CORROSION SCC NAMLT TOTAL SCORE 4 = BEST, 1 = WORST WIRE ARC HVOF FLAME SPRAY COLD SPRAY PLASMA SPRAY D-GUN

25 Task 5 Analysis and Roadmap Two scenarios investigated: use of wire arc TS by shipyard, and use of wire arc TS by subcontractor Scenario 1 - Use of wire arc TS within shipyard, by shipyard personnel Shipyards are familiar with most TS processes and likely already know what would be required to implement TS well within capability of shipyards At a minimum, implementation of wire arc TS at shipyard would require: Confirmation of end use application(s) for wire arc TS Approval of all authorizing entities to use process shipboard, including changes to relevant drawings and procedures Procurement and installation of equipment Establishment of necessary training curriculum Address environmental, safety, and occupational health issues Implementation of wire arc TS process shipboard. Assumed that wire arc TS system costs approximately $500,000, based on past experience with same or similar system acquisitions. 25

26 Task 5 Analysis and Roadmap (cont d.) Scenario 2 - Use of wire arc TS by subcontractor Assumptions: Surface area to be treated is 800 square feet of 5083 alloy Al All paint, outfitting, wires, interfering items removed prior to TS coating Shipyard to provide pier and lifting support for equipment as required. Structure to be treated fully scaffolded, to include drapes to capture paint chips, grit blasting media, powder, etc. Blasting / spraying operation NOT considered Hot Work (will not require Fire Watch). Subcontractor to provide all supervision, labor, materials, and equipment to accomplish TS coating. Total operator time for TS application = 38.2 man-hours per 800 foot2 area However, when including personnel and equipment transport, setup of containment areas, masking, blasting, coating, waste treatment, and removal of containment, as many as 72 hours may be more reasonable for the entire operation. 26

27 Task 5 Analysis and Roadmap (cont d.) Scenario 2 - Use of wire arc TS by subcontractor For costing, considered operations in Norfolk, VA and Mobile, AL Norfolk, VA - TOTAL ROM Pricing Estimate = $125,000 - $135,000 Mobile, AL - TOTAL ROM Pricing Estimate = $165,000 - $175,000 Above pricing equates to between $156 and $218 per square foot RESULTS: While second scenario might be worthwhile in the short term, longer term investment in TS processes by the shipyards would yield eventual cost avoidance ROI - sensitized aluminum-related repair costs for CG 47 class cruisers are approx $8-10 Million annually 27

28 Conclusions TS CP aluminum has the potential to remediate the propensity for SCC on ship structures. Wire arc TS has best potential for transition to a shipyard environment Demonstrated capability of both reducing corrosion and enhancing paint adhesion for the given application. Business case demonstrates that, while using subcons to apply wire arc CP TS aluminum shipboard will derive benefits in the short term, bringing this capability in-house will provide benefits for the shipyards in the long term ROI is significant 28

29 BACKUP SLIDES 29

30 Task 4 Distortion

31 Task 4 Distortion

32 Task 4 NAMLT

33 Task 4 NAMLT

34 Next Steps (Proposed Phase II) Additional testing to focus specifically on wire arc TS process Longer duration SCC testing Metallurgy Wear Fatigue (high cycle) Shipboard evaluations? Initiate testing on cold spray applied aluminum (next gen) 34

35 Sensitization and SCC Residual stress from forming or welding, or applied stress (e.g. ship motion in a seaway)- very difficult to avoid Painted aluminum alone is NOT an effective barrier Tensile Stress At Surface SCC Sensitization: Mg 2 Al 3 β phase forms at higher temp and migrates to grain boundary Even strain-hardened tempers H116 and H321 will form β phase after years of exposure at in-service temperatures <150F Corrosive Environment Objective: Break one or more legs of the triangle to avoid SCC Susceptible Material 35

36 Electric Arc Thermal Spray Two wires are melted in arc, and propelled onto surface by compressed air Particles pancake onto surface, solidify, and contract Subsequent passes build additional thickness at ~90% densification, 10% voids, typ. to inch thickness A mature, fairly cheap and quick* metallic coating, but voids are a concern NMC R2519 Rapid Response project For CVN application, Thermal Sprayed Commercially Pure (CP) aluminum was applied to sensitized Al substrate Worst case: NO paint was applied While untreated samples failed, Thermal Spray passed both 1000 hour scribed, acidified salt fog test (no indications) and 6 month SCC U-bend tests (no failures) -Voids are STILL a concern for 35 yr life *NSRP NASSCO/DTRC Procedure Handbook for Shipboard Thermal Sprayed Coating Applications 3/92 36

37 Thermal Spray + Paint Can Work As a System Even without paint, Thermal Sprayed CP Aluminum is an effective barrier to environment for substrate (R2519, 6 month SCC and 1000 hour acidified salt fog) WITH paint, the combination should provide an extremely durable composite environmental barrier Thermal sprayed CP Aluminum, 90% densified With no magnesium in the alloy, CP Aluminum coating is NOT SUSCEPTIBLE to sensitization Combined with an LSA paint, this will also preclude further sensitization of the substrate Top coat, LSA or non-skid LSA Low viscosity tie coat Substrate aluminum 37

38 Project Activities vs. WBS Task 1 Application Scenarios COMPLETED Confirmed key application areas, target sizes, and configurations Selected optimal thermal spray method for targeted application Drafted and submitted Use Case Scenarios Report (D) Task 2 Develop Test Matrix COMPLETED Developed test matrix to conduct testing Testing to quantify sensitization, SCC corrosion resistance, and durability of selected thermal spray CP coatings, both with and without LSA paint Drafted and submitted Test Matrix (D) (D) = contract deliverable 38

39 Test Matrix (final) 39

40 Updated Thermal Spray Information Applicable Specifications MIL-STD-2138A, Military Standard, Metal Sprayed Coatings for Corrosion Protection Aboard Naval Ships Cancelled as of 19 February 2009 MIL-C-81751B, Military Specification, Coating, Metallic-Ceramic Inactive for new design as of 28 August 1996 NACE No. 12/AWS C2.23M/SSPC-CS 23.00, Specification for the Application of Thermal Spray Coatings (Metallizing) of Aluminum, Zinc, and Their Alloys and Composites for the Corrosion Protection of Steel Active, relevant, but focused primarily on steel MIL-STD-1687A, Department of Defense Manufacturing Process Standard, Thermal Spray Processes for Naval Ship Machinery Applications Active, preferred by NSWCCD Procedure Handbook for Shipboard Thermal Sprayed Coating Applications Active, relevant to NSRP 40

41 Task 3 Test Specimen Fabrication and Coating COMPLETED TEST PLAN COMPLETED Fabricated 5xxx Al alloy test specimens of selected configuration (flat panels) Panels coated with CP Al (using flame spray, wire electric arc, and HVOF) Thermal Spray Solutions Inc., Chesapeake, VA Wire arc and flame spray completed and sent to CTC HVOF completed and sent to CTC CTC applied LSA coating 41

42 Test Plan Evaluation Matrix (REVISED) 42

43 UPDATED Schedule of Milestones and Deliverables Deliverable Quarterly Report 1 (CTC) & Use Case Scenario Report (CTC with input from NNS, BIW, MMC, Ingalls, NSWCCD, and NAVSEA) upon completion of Task 1 Test Matrix (CTC with input from NNS, BIW, MMC, Ingalls, NSWCCD, and NAVSEA) upon completion of Task 2 Due Date April 1, 2016 April 29, 2016 Quarterly Report 2 (CTC) June 24, 2016 Quarterly Report 3 (CTC) September 30, 2016 Quarterly Report 4 (CTC) December 30, 2016 Quarterly Report 5 (CTC) April 15, 2017 Final Report / Test Report (CTC) upon completion of Task 5. Will include progress made against objectives, test data and results, benefits (including potential impacts in new construction), conclusions, and recommendations (roadmap for implementation). June 30,