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Corrosion Failures and MitigationIn Hydrided Environments

Dennis J. SchumerthASME Fellow & Principal

DBA Titanium Tubular Consultants

Cell 714-393-1013E-mail schumert@AOL.com , E-mail dennisschumerth@Gmail.com

Web Site: TitaniumTubularConsultants.com

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DISCLAIMER

The information and data contained herein are derived from a variety of sources which this author believes to be reliable.  The use and application of the data and material contained within this presentation, either intended or implied, shall be the responsibility of the user and are not 

intended as claims, warranties, either expressed or implied or fitness  of purpose.Because it is not possible to anticipate specific uses and operating conditions, we urge you to 

consult with technical service personnel on your particular application.

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presentation  overview

Hydriding 101 CP TitaniumR50400

Superferritic SS(Sea Cure™ S44660)

What is it ???

TitaniumFormation of Brittle

Hydrides & Cracking

Superferritic SSFracture & Reduced

Ductility

Al & C. Steel Reduced Ductility &

Fracture

“Damaging” Condition in Metals Where the Solubility

Threshold of H2 is Exceeded

Result – Loss of Structural Integrity

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Hydriding 101

Hydriding 101 CP TitaniumR50400

Superferritic SS(Sea Cure™ S44660)

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Hydriding 101 CP TitaniumR50400

EFFECT of MOISTURE ABSORPTION on HYDROGEN

% H20 Hydrogen Pickup (ppm)

0 4.4800.5 51,0001.0 7002.0 73.3 105.3 17

10.2 1122.5 037.5 056.2 0600oF (316oC @ 800 psi – 96 Hours Exposure

Superferritic SS(Sea Cure™ S44660)

Hydriding 101 CP TitaniumR50400

Superferritic SS(Sea Cure™ S44660)

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Hydriding 101Susceptible Materials

CP TitaniumR50400

Aluminum C. Steel Ferritic SS Titanium

anodic cathodic

Superferritic SS(Sea Cure™ S44660)

case studies

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Case Study 1

Sea water cooling Gr. 2 ASTM B-338 titanium tubing Manual control IC system SCE voltage range: Est. @ -1.5 -2.0V 3000 ppm (est.) breakthrough saturation

Observations (Ref: IJPGC & NACE)

Laboratory testing confirms hydriding of Gr. 2 titanium does not occur up to potentials of -1.20VSCE

Under the same testing, hydride layers are detected at potentials of greater than > -1.20VSCE

Actual operating potentials estimated @ - 1.60VSCE to - 2.00VSCE

Predicted threshold potential for hydrogen @ -1.20 VSCE to - 1.40 VSCE

Residual stress (typ) influences hydride phase orientation but does not effect hydrogen absorption or penetration rate No thru-wall failures Mechanical testing OK.

Mitigation

Seal affected tubes System uprate to Automatic Potential Control

Case Study 2 Ref: (EPRI & CSC)

Sea water cooling ASTM B-338 Gr. 2 titanium tubing Peripheral titanium tube hydriding Localized tube cracking & deposits on protruding tube ends Calcium and magnesium deposits (calcareous) = pH Δ Excessive CP voltages OE-installed tubesheet and waterbox coating Waterbox isolation during tidal swings Lack of preventative maintenance program

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Case Study 2

Reasonable IC set points

Attack and rupture in HAZ Attack in parent metal Little to no attack in the weld zone

INITIAL DESIGN SET POINTS

TUBESHEET ‐0.7 to ‐0.9 V Ag/AgCl

WATERBOX ‐1.0 V Ag/AgCl

Case Study 2

Mitigation Recommendations

Completed Titanium Rebuild All Welded – No Protruding Tube Ends Implement Best Practices Tube Cleaning

Recommended Updated, Auto Potential IC System Set Points @ ≤ - 0.90VSCE to -1.0VSCE

Regular Instrument Calibration Periodic Replacement of Control Cards Individual Waterbox Rectifiers

NOTE: Client ultimately opted to remove all IC recommendationsrelying only on the titanium tube/t.s. interface and waterbox coating.

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Case Study 3

Observations

Sea water cooling Tube material: Superferritic SS - Sea Cure ® (UNS-44660) Multiple failure characteristics

Mid-span chloride pitting corrosion (unrelated to hydriding)Disintegrated tube endsTube fractures w/i tubesheet & extending Into unexpanded area

Confirmed hydriding thru RFT EC

Case Study 3

Observations

Tube cracking in or near tubesheet Disintegrated tube ends Failure mechanism + CP potentials @ > - .80V SCE

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Case Study 3

Mitigation

Remedy: stabilizing sleeves

Install automatic CP potentials @ < - .80V SCE

Final solution: Unit(s) demolished in 2010 for replacement facility

Sidebar Commentary

Bright Anneal or Open-Air/Pickle PWHT Produced Material Exhibit

Similar Hydriding Tendencies

Case Study 4

Observations

Gr. 2 B-338 Titanium Early 80’s Installation Muntz Metal Tubesheets Hydrogen Analysis – Plant “X” Protruding Tube End Sections

Discovery

Tube End Fracture Overzealous IC System Identified Aggressive Tube Cleaner Operation Caused End Fractures ???

Mitigation

Upgrade IC System (proposed)

Trim Tube Ends (proposed)

Stabilize Sleeve Damaged Tubes (proposed)

Sample ID H2 Content (ppm) Sample 1: 1365 ppm Sample 2: 1593 ppm Sample 3: 1624 ppm Sample 4: 1672 ppm ASTM Max. Allowed 150 New Tubes Typical < 100 ppm

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Titanium Tubing

“Random, Longitudinal, OD-Initiated, Hydride Assisted Tube Cracking”

What’ happening ?????Holy WaterMinor hydride needles present Hydrides appear to align radially direction under a stress field Vibration ruled out No IC or sacrificial system present to generate hydrogen Radiolithic hydrogen ruled out Residual Stress levels normal (10 – 15 ksi)

What it really is ??????Crack propagation from “scratches” imparted during retube 35 years ago……

Hydriding Facts, Myths & Misnomers

Hydriding Facts, Myths & Misnomers

Superferritic SS & C. Steel Tubing

Bend Ductility in Hydrogen-Charged Tubes can be Reversible in Superferritic & Alloy SteelPredicated on Immediate and Permanent Removal of Hydrogen Source

REVERSAL CONDITION NOT POSSIBLEIN CRACKED OR DAMAGED TUBES

Superferritic Structure Appear More Prone to Hydrogen-Induced Failure

Titanium Structure Appears Less Prone to Hydrogen Induced Failure

Suggested Damage ThresholdSuperferritic SCE Threshold Levels: - 0.90 VSCE but more approaching - 0.80 VSCE

Titanium SCE Threshold Levels at -1.20 VSCE to - 1.40 VSCE

What’s Been Reported

What's Also Been Documented

Lazarus Effect ??

What's Not Been Reported

“xxx”

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Hydriding…..how to check for it???

Destructive Analysis

Surface Replication (Comparison) Process )

Visual Inspection (I.E., White, Calcareous, Flowered Appearance Powder)

Color Change to Gray or Silvery Appearance

Check IC or CP System

ID EC may be Performed – ID Wall Thinning is Not Typical

SEM can Identify the Fracture Morphology

Hydriding May be Associated With Higher Levels of Stress Concentration

Hydriding….How to Avoid it???

Proper equipment design

Eliminate detrimental galvanic couples

Individual rectifiers are recommended for each waterbox

Consistent, accountable maintenance programs

Anodes: Cast iron or aluminum preferred. Zinc is O.K.

Magnesium should be avoided due to its high negative potential

Anodes should not be placed closer than 30 inches from the tubesheet

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Varying CP systems polarization limits to one value at the tubesheet and another value at the waterbox/channel may be ideal but due to condenser dynamics…..all but impossible and ultimately…… “Rube Goldbergish”

Anodes should be selected to produce negative potentials of:≤ - 0.80VSCE maximum for ferritic stainless steels ≤ - 0.90VSCE to -1.0VSCE for titanium

Cautionary Note: EC signals may resemble wall loss but actually represents a change in material resistivity

One Case Study the condenser was completely upgraded without the benefit of either an IC or sacrificial system rather relying entirely in the integrity of a full waterbox coating

Most if not all fractures occur at protruding ends – tube/t.s. interface

EPRI NDE testing continues to identify hydriding

Pitfalls & Lessons Learned

References 1. Fulford, J. Paul, FP&L Juno Beach, Schutz, Ronald, TIMET, Lisenbey, Robert, FP&L Juno Beach. (St. Lucie Unit 1 and Turkey Point Unit

CHARACTERIZATION OF TITANIUM CONDENSER TUBE HYDRIDING AT TWO FLORIDA POWER and LIGHT COMPANY PLANTS – Addcontributions by Grauman, James, TIMET, Collard, Steve, Heise, Wolfgang, Joseph, Mark and Newman, Randy, (FP&L) - ASME Paper 1981 (87-JPGCF)

2. Schutz, R.W. and Grauman, J.S., TIMET Division - Determination of Cathodic Potential Limits for Prevention of Titanium Tube Hydride Embrittlement inSaltwater - NACE 89- Paper 110

3. Nekoksa. George, Corrosion Failure Analysis and Gutherman, Brian, Florida Power Corporation - Test Results From Electrochemical Exposure Racks aCrystal River Nuclear Power Plant - NACE 91 – Paper 275

4. Radmerski, L.S., Colt Industries, Eckenrod, J.J., and Pinnow, K.E., Colt Industries and Kovach, C.W., Colt Industries, Trent Tube Division - Cathodic Protection of Seawater-Cooled Powerplant Condenser Operating with High Performance Ferritic Stainless Steel Tubing - NACE 85 – Paper 208

5. Grubb, J.F., Allegheny Ludlum Steel Corp - Hydrogen Embrittlement of Superferritic Stainless Steels – Paper 8410-028 6. Kovach, C.W., and Redmond, J.D., TMR - Experience with High Performance Stainless Steel tubing in Power Plant Condensers - NACE 91 – Paper 507. TIMET Publication – “Corrosion Resistance of Titanium”, January, 1999 8. Schumerth, D.J., Valtimet - et’ al’ - Valtimet Publication – TITANIUM TUBING DESIGN and FABRICATION HANDBOOK – 2003 9. Det Norske Veritas, May, 2009 - The Evaluation of Main Condenser Cathodic Protection

System at Point Lepreau Generating Station 10. RPC Report J39581 - Assessment of Hydriding on Ti-Condenser 11. Land, Nick - Evaluation of Failed Sea Cure Condenser Tubes From Port Everglades Unit 3, 1999, Land, Nick - FPL Test Report JPS-DSR-3974 12. Nishina, Dean, Executive Director – Hawaii Electric - HECO Division of Consumer Advocacy Position Statement – November 18, 2010 Docket Twenty No. 2010-0126 13. Fulford, P., and Peroni, B., Ferritic Stainless Steel Tube Problems at the Cape Canaveral and Port Everglades Station - EPRI Seminar – CS 4329-SR (114. Land, Nick, and Schoolery, Dave, Research and Evaluation Laboratory – Power Delivery Services – Evaluate Failed Sea-Cure Condenser Tube from Po

Everglades Plant –FP&L Test Report JPS-DRS-3974 15. Christensen Materials Engineering Report March 21, 2012. Hawaii Electric (HECO), Kahe 1, Condenser 12 16. Hartt, W.H., Liu, L., Fatigue Properties of Hydrided Titanium Condenser Tubes - NACE, 1992 17. Divi, S.C., Grauman, J., Examination of a Cracked Grade 2 Titanium Surry Unit Main Condenser Tube - TIMET Report – October, 2011 18. Schumerth, D.J., Valtimet, Inc. - Titanium Powerplant Surface Condenser Tubing – 40

Years and 600,000,000 ft later, EnergyTech Magazine (ASME Publication) – June, 2011, Titanium Still Going Strong After 40 Years, Power Magazine July, 2011

19. Kostrivsas, A., Smith, L.S., Gittos, M.F., TWI Ltd, Cambridge, UK – Sustained Load Cracking in Titanium Alloys 10th World Conference on Titanium 13-July, Hamburg, Germany

20. Hydrogen Embrittlement in Titanium and Superferritic Stainless Steel Steam Surface Condenser Tubing, D.Schumerth, TTC & Thomas Demers, NP Power: EPRI and CSC Publications 2013

1. Fulford, J. Paul, FP&L Juno Beach, Schutz, Ronald, TIMET, Lisenbey, Robert, FP&L Juno Beach. (St. Lucie Unit 1 and Turkey Point Unit

CHARACTERIZATION OF TITANIUM CONDENSER TUBE HYDRIDING AT TWO FLORIDA POWER and LIGHT COMPANY PLANTS – Addcontributions by Grauman, James, TIMET, Collard, Steve, Heise, Wolfgang, Joseph, Mark and Newman, Randy, (FP&L) - ASME Paper 1981 (87-JPGCF)

2. Schutz, R.W. and Grauman, J.S., TIMET Division - Determination of Cathodic Potential Limits for Prevention of Titanium Tube Hydride Embrittlement inSaltwater - NACE 89- Paper 110

3. Nekoksa. George, Corrosion Failure Analysis and Gutherman, Brian, Florida Power Corporation - Test Results From Electrochemical Exposure Racks aCrystal River Nuclear Power Plant - NACE 91 – Paper 275

4. Radmerski, L.S., Colt Industries, Eckenrod, J.J., and Pinnow, K.E., Colt Industries and Kovach, C.W., Colt Industries, Trent Tube Division - Cathodic Protection of Seawater-Cooled Powerplant Condenser Operating with High Performance Ferritic Stainless Steel Tubing - NACE 85 – Paper 208

5. Grubb, J.F., Allegheny Ludlum Steel Corp - Hydrogen Embrittlement of Superferritic Stainless Steels – Paper 8410-028 6. Kovach, C.W., and Redmond, J.D., TMR - Experience with High Performance Stainless Steel tubing in Power Plant Condensers - NACE 91 – Paper 507. TIMET Publication – “Corrosion Resistance of Titanium”, January, 1999 8. Schumerth, D.J., Valtimet - et’ al’ - Valtimet Publication – TITANIUM TUBING DESIGN and FABRICATION HANDBOOK – 2003 9. Det Norske Veritas, May, 2009 - The Evaluation of Main Condenser Cathodic Protection

System at Point Lepreau Generating Station 10. RPC Report J39581 - Assessment of Hydriding on Ti-Condenser 11. Land, Nick - Evaluation of Failed Sea Cure Condenser Tubes From Port Everglades Unit 3, 1999, Land, Nick - FPL Test Report JPS-DSR-3974 12. Nishina, Dean, Executive Director – Hawaii Electric - HECO Division of Consumer Advocacy Position Statement – November 18, 2010 Docket Twenty No. 2010-0126 13. Fulford, P., and Peroni, B., Ferritic Stainless Steel Tube Problems at the Cape Canaveral and Port Everglades Station - EPRI Seminar – CS 4329-SR (114. Land, Nick, and Schoolery, Dave, Research and Evaluation Laboratory – Power Delivery Services – Evaluate Failed Sea-Cure Condenser Tube from Po

Everglades Plant –FP&L Test Report JPS-DRS-3974 15. Christensen Materials Engineering Report March 21, 2012. Hawaii Electric (HECO), Kahe 1, Condenser 12 16. Hartt, W.H., Liu, L., Fatigue Properties of Hydrided Titanium Condenser Tubes - NACE, 1992 17. Divi, S.C., Grauman, J., Examination of a Cracked Grade 2 Titanium Surry Unit Main Condenser Tube - TIMET Report – October, 2011 18. Schumerth, D.J., Valtimet, Inc. - Titanium Powerplant Surface Condenser Tubing – 40

Years and 600,000,000 ft later, EnergyTech Magazine (ASME Publication) – June, 2011, Titanium Still Going Strong After 40 Years, Power Magazine July, 2011

19. Kostrivsas, A., Smith, L.S., Gittos, M.F., TWI Ltd, Cambridge, UK – Sustained Load Cracking in Titanium Alloys 10th World Conference on Titanium 13-July, Hamburg, Germany

20. Hydrogen Embrittlement in Titanium and Superferritic Stainless Steel Steam Surface Condenser Tubing, D.Schumerth, TTC & Thomas Demers, NP Power: EPRI and CSC Publications 2013

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Thank you for your attention

Dennis J. SchumerthASME Fellow & Principal

DBA Titanium Tubular Consultants

Cell 714-393-1013E-mail schumert@AOL.com , E-mail dennisschumerth@Gmail.com

Web Site: TitaniumTubularConsultants.com

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