thermal spray aluminum for aluminum corrosion prevention · pdf file• scra – prime...

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

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!

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 2016 – 30 Jun 2017

• $149,986 total funding

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

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)

7

Project Activities vs. WBS (cont’d.)

• Task 4 – Coating Quality

Flame spray coated 5456 panels,

painted (left) and unpainted (right)

Wire arc coated 5456 panels, painted

(left) and unpainted (right)

HVOF coated 5456 panels, painted

(left) and unpainted (right)

8


• Task 4 – Quality – Coating Thickness Test Type Material Size Process Coating Panel ID

As-received Panel

Dimension (in)

As Sprayed Panel

Dimension (in)

Calculated Coating

Thickness (in)

Bends 5456 2"x12"

Wire Arc

TS only

M1-WA-TS-B1 0.253 - 0.255 0.263 - 0.265 0.010

M1-WA-TS-B2 0.253 - 0.255 0.262 - 0.265 0.009 - 0.010

M1-WA-TS-B3 0.253 - 0.255 0.263 - 0.265 0.010

TS and LSA

M1-WA-TSP-B1 0.253 - 0.255 0.264 - 0.267 0.011 - 0.012

M1-WA-TSP-B2 0.253 - 0.255 0.265 - 0.267 0.012

M1-WA-TSP-B3 0.253 - 0.255 0.263 - 0.267 0.010 - 0.012

HVOF

TS only

M1-HV-TS-B1 0.253 - 0.255 0.265 - 0.267 0.012

M1-HV-TS-B2 0.253 - 0.255 0.264 - 0.266 0.011

M1-HV-TS-B3 0.253 - 0.255 0.260 - 0.262 0.007

TS and LSA

M1-HV-TSP-B1 0.253 - 0.255 0.260 - 0.262 0.007

M1-HV-TSP-B2 0.253 - 0.255 0.261 - 0.263 0.008

M1-HV-TSP-B3 0.253 - 0.255 0.261 - 0.263 0.008

Flame Spray

TS only

M1-FS-TS-B1 0.253 - 0.255 0.261 - 0.263 0.008

M1-FS-TS-B2 0.253 - 0.255 0.262 - 0.264 0.009

M1-FS-TS-B3 0.253 - 0.255 0.262 - 0.264 0.009

TS and LSA

M1-FS-TSP-B1 0.253 - 0.255 0.262 - 0.265 0.009 - 0.010

M1-FS-TSP-B2 0.253 - 0.255 0.264 - 0.266 0.011

M1-FS-TSP-B3 0.253 - 0.255 0.259 - 0.262 0.006 - 0.007

Bends 5083 2"x12"

Wire Arc

TS only

M2-WA-TS-B1 0.246 - 0.248 0.257 - 0.260 0.011 - 0.012

M2-WA-TS-B2 0.246 - 0.248 0.259 - 0.260 0.012 - 0.013

M2-WA-TS-B3 0.246 - 0.248 0.258 - 0.261 0.012 - 0.013

TS and LSA

M2-WA-TSP-B1 0.244 - 0.246 0.257 - 0.260 0.014

M2-WA-TSP-B2 0.246 - 0.248 0.259 - 0.261 0.013

M2-WA-TSP-B3 0.246 - 0.248 0.259 - 0.260 0.012 - 0.013

HVOF

TS only

M2-HV-TS-B1 0.246 - 0.247 0.253 - 0.255 0.007 - 0.008

M2-HV-TS-B2 0.246 - 0.247 0.254 - 0.257 0.008 - 0.010

M2-HV-TS-B3 0.246 - 0.247 0.253 - 0.255 0.007 - 0.009

TS and LSA

M2-HV-TSP-B1 0.246 - 0.247 0.255 - 0.256 0.009

M2-HV-TSP-B2 0.246 - 0.247 0.253 - 0.254 0.007

M2-HV-TSP-B3 0.246 - 0.247 0.255 - 0.258 0.009 - 0.011

Flame Spray

TS only

M2-FS-TS-B1 0.246 - 0.248 0.254 - 0.257 0.008 - 0.009

M2-FS-TS-B2 0.246 - 0.247 0.254 - 0.257 0.008 - 0.010

M2-FS-TS-B3 0.246 - 0.247 0.254 - 0.257 0.008 - 0.010

TS and LSA

M2-FS-TSP-B1 0.246 - 0.247 0.255 - 0.257 0.009 - 0.010

M2-FS-TSP-B2 0.246 - 0.247 0.255 - 0.258 0.009 - 0.011

M2-FS-TSP-B3 0.245 - 0.246 0.254 - 0.257 0.009 - 0.011

Generally between 0.008₺

and 0.012₺

9

Project Activities vs. WBS (cont’d.) • Task 4 – Adhesion – Three Point Bend

Test Rig

10

Project Activities vs. WBS (cont’d.) • 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 5083

11

Project Activities vs. WBS (cont’d.) • 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

12

Project Activities vs. WBS (cont’d.) • Task 4 – Adhesion – Bends (cont’d.)

HVOF CP Al on 5456 – note failure of

thermal spray from substrate HVOF CP Al on 5083

13


HVOF CP Al / LSA on 5456 HVOF CP Al / LSA on 5083

14


Wire Arc CP Al on 5456 Wire Arc CP Al on 5083

15


Wire Arc CP Al on 5456 Wire Arc CP Al / LSA on 5083

16


• Task 4 – Adhesion (PATTI) – Pull-Off

• Results – HVOF best

– Wire arc 2nd 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

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

18



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

19



Flame spray CP Al on 5456

after 500 hours NSS







20



Wire arc CP Al on 5083 after

500 hours NSS





Results: no corrosion, no scribe

undercut

21



HVOF CP Al on 5083 after 500

hours NSS







22



Flame spray CP Al on 5083

after 500 hours NSS







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

24


• Task 4 – Conduct Testing

– Conclusions

PROCESS CAPABILITY AVAILABILITY APPLICABILITY QUALITY DISTORTIONADHESION -

BENDS

ADHESION -

PULL-OFFSCORROSION SCC NAMLT

TOTAL

SCORE

WIRE ARC 3 2 3 4 4 4 3 4 4 4 35

HVOF 3 2 3 4 4 2 4 2 4 4 32

FLAME

SPRAY2 2 3 4 4 0 2 2 4 4 27

COLD

SPRAY3 1 1 0 0 0 0 0 0 0 5

PLASMA

SPRAY3 1 1 0 0 0 0 0 0 0 5

D-GUN 2 1 1 0 0 0 0 0 0 0 4

4 = BEST, 1 = WORST

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.

26

Project Activities vs. WBS (cont’d.) • 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.

27

Project Activities vs. WBS (cont’d.) • 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

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

29

BACKUP SLIDES

30

Project Activities vs. WBS (cont’d.) • Task 4 – Distortion 5456

31

Project Activities vs. WBS (cont’d.) • Task 4 – Distortion 5083

32

Project Activities vs. WBS (cont’d.) • Task 4 – NAMLT 5456

33

Project Activities vs. WBS (cont’d.) • Task 4 – NAMLT 5083

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)

35

Sensitization and SCC

SCC

Corrosive Environment

Tensile Stress

At Surface

Susceptible Material

Even strain-hardened tempers H116 and H321 will form β phase after years of exposure at in-service temperatures <150F

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

Sensitization: Mg2Al3 ‘β phase’ forms at higher temp and migrates to grain boundary

Objective: Break one or more legs of the triangle to avoid SCC

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 0.010 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

37

Thermal Spray + Paint Can Work – As a System

With no magnesium in the alloy, CP Aluminum coating is NOT SUSCEPTIBLE to sensitization

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

Combined with an LSA paint, this will also preclude further sensitization of the substrate

Substrate aluminum

Low viscosity tie coat

Top coat, LSA or non-skid LSA

Thermal sprayed CP Aluminum, 90% densified

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

39

Test Matrix (final)

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

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

42

Test Plan Evaluation Matrix (REVISED)

43

UPDATED Schedule of Milestones and Deliverables

Deliverable Due Date

Quarterly Report 1 (CTC) & Use Case Scenario Report (CTC with input from NNS,

BIW, MMC, Ingalls, NSWCCD, and NAVSEA) upon completion of Task 1

April 1, 2016

Test Matrix (CTC with input from NNS, BIW, MMC, Ingalls, NSWCCD, and NAVSEA)

upon completion of Task 2

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, 2017

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