Nickel InstituteNickel Institute

Corrosion by Process WatersCorrosion by Process Waters

R. W. RossR. W. RossConsultantConsultant

Nickel Institute Nickel Institute

SummarySummary

Scaling and CorrosionScaling and Corrosion

Effects of VelocityEffects of Velocity

Biological EffectsBiological Effects

ChloridesChlorides

Rouging of SSRouging of SS

Water Chemistry EffectsWater Chemistry Effects

CorrosionCorrosion

• Dissolved OxygenDissolved Oxygen

• ChloridesChlorides• pHpH

• HardnessHardness

• TemperatureTemperature

ScaleScale

• Dissolved SolidsDissolved Solids

• Calcium IonsCalcium Ions• pHpH

• TemperatureTemperature

Water Chemistry EffectsWater Chemistry Effects

Corrosion Of Carbon Steel Corrosion Of Carbon Steel In WaterIn Water

0

10

20

30

0 5 10 15

72 ºF (22 ºC)

104 ºF (40 ºC)

Co

rro

sio

n R

ate,

mp

yC

orr

osi

on

Rat

e, m

py

pH of WaterpH of Water

0.25

0.51

0.76

Co

rro

sio

n R

ate,

mm

/yC

orr

osi

on

Rat

e, m

m/y

Corrosion Of Carbon Steel Corrosion Of Carbon Steel In Low-velocity WaterIn Low-velocity Water

Corrosion Of Carbon Steel Corrosion Of Carbon Steel Effect Of Velocity In SeawaterEffect Of Velocity In Seawater

0

25

50

0 5 10 15 20 25

~ 72 ºF (22ºC )

ft/sec (m/s)

Co

rro

sio

n R

ate,

mp

yC

orr

osi

on

Rat

e, m

py

Co

rro

sio

n R

ate,

mm

/yC

orr

osi

on

Rat

e, m

m/y1.27

0.64

(1.5) (3.0) (4.7) (6.1) (7.6)

Erosion-corrosion - InletErosion-corrosion - Inlet

Erosion-corrosionErosion-corrosion

Flow

Erosion-corrosionErosion-corrosionTube BlockageTube Blockage

Flow

High-velocity SeawaterHigh-velocity Seawater >120 fps (36.6 m/s)>120 fps (36.6 m/s)

Corrosion Corrosion Rate,Rate,

Alloy Alloy mpympy mm/ymm/y

625/C-276625/C-276 <1 <1 < 0.03< 0.03

400/K-500400/K-500 <1 <1 < 0.03< 0.03

718/725/925718/725/925 <1 <1 < 0.03< 0.03

T-304/T-316T-304/T-316 <1 <1 < 0.03< 0.03

C SteelC Steel >300 >300 > 7.62> 7.62

Biological EffectsBiological EffectsMacrofoulingMacrofouling

• MusselsMussels

• ClamsClams

• BarnaclesBarnacles

• Plant LifePlant Life

Biological EffectsBiological EffectsMacrofoulingMacrofouling

Bacteria Effects - MICBacteria Effects - MIC(Microbiologically Induced Corrosion)(Microbiologically Induced Corrosion)

SpeciesSpecies OxygenOxygen MetalsMetals Corrosive Corrosive

DesulfovibrioDesulfovibrio No No Fe, Al, CuFe, Al, Cu Sulfide Sulfide

ThiobacillusThiobacillus Yes Yes Fe, CuFe, Cu Sulfuric AcidSulfuric Acid

GallionellaGallionella Yes Yes FeFe FeFe++++ to Fe to Fe++++++

MnMn++++ to Mn to Mn++++++

Type 304 SS Type 304 SS water tank water tank

8 months of 8 months of serviceservice

GuamGuam

Bacteria Effects - MICBacteria Effects - MIC

Bacteria Effects - MICBacteria Effects - MIC (Type 304 SS, Before Cleaning)(Type 304 SS, Before Cleaning)

Bacteria Effects - MICBacteria Effects - MIC (After Cleaning)(After Cleaning)

0.15 in. (3.8) mm)

Max. Attack

Bacteria Effects - MICBacteria Effects - MIC (After Cleaning - No Attack)(After Cleaning - No Attack)

Prevention Of MICPrevention Of MIC

• Keep The System CleanKeep The System Clean

• Keep Water Flow > 6 fps (2 m/s)Keep Water Flow > 6 fps (2 m/s)

• Use Bactericide:Use Bactericide:

– ChlorineChlorine

– Chlorine DioxideChlorine Dioxide

– HypochloriteHypochlorite

– OzoneOzone

– Non-oxidizingNon-oxidizing

Prevention Of MICPrevention Of MIC

• Use Continuous CleaningUse Continuous Cleaning

• Use High Pressure HydrolancingUse High Pressure Hydrolancing

• Use Stainless Steel ScrapersUse Stainless Steel Scrapers

(Hard to Remove or Heavy Deposits)(Hard to Remove or Heavy Deposits)

• Use Alloy Resistant to MICUse Alloy Resistant to MIC

Prevention Of MIC - 6% Mo ALLOYPrevention Of MIC - 6% Mo ALLOY

Effects of ChloridesEffects of Chlorides

Crevice Corrosion Type 303Crevice Corrosion Type 303

Stainless SteelsStainless SteelsLocalized Corrosion ResistanceLocalized Corrosion Resistance

AlloyAlloy PREPRE

304 18 304 18

316 25316 25

317 30317 30

2205 342205 34

2505 372505 37

2507/Alloy 100 412507/Alloy 100 41

6% Mo Alloys 40 - 456% Mo Alloys 40 - 45

Nickel AlloysNickel AlloysLocalized Corrosion ResistanceLocalized Corrosion Resistance

Alloy Alloy PRE PRE

316 25316 25

6% Mo 40 – 456% Mo 40 – 45

625625 52 52

22/622 6522/622 65

C-276C-276 69 69

20002000 76 76

686686 76 76

5959 76 76

Stainless Steels for Use in WatersStainless Steels for Use in Waters

Potable waterPotable water Type 304 < 200 ppm chloridesType 304 < 200 ppm chloridesType 316 < 1000 ppm chloridesType 316 < 1000 ppm chlorides

River waterRiver water Risk of MIC if water is not treatedRisk of MIC if water is not treatedUse type 316 or higher Mo grades:Use type 316 or higher Mo grades: 2205 904L2205 904L 2507 6Mo2507 6Mo

Well waterWell water Risk of MIC if water is not treatedRisk of MIC if water is not treatedUse type 316 or higher Mo gradesUse type 316 or higher Mo grades

Do not confuse Chloride ClDo not confuse Chloride Cl-- and Chlorine Cl and Chlorine Cl22

Maximum Concentration (ppm) in Maximum Concentration (ppm) in Water to Avoid Crevice CorrosionWater to Avoid Crevice Corrosion

Chloride ClChloride Cl-- Chlorine ClChlorine Cl22

304304 200200 22

316316 10001000 44

Shock dosing, such as 25 ppm chlorine for 24 hours, is common practice Shock dosing, such as 25 ppm chlorine for 24 hours, is common practice and has not been found to cause problems.and has not been found to cause problems.

Stress Corrosion Cracking (SCC)Stress Corrosion Cracking (SCC)

Steam Line

Chloride SCCChloride SCC Duplex vs T-316 Stainless Steel Duplex vs T-316 Stainless Steel

0

200

400

600

1 10 100 1000 10000

Chlorides, ppm

Tem

per

atu

re, F

(C

) (315)

(204)

(93)

Type 316

18 Cr Duplex

22 Cr Duplex

No cracking below lines

Effect of Nickel Content onEffect of Nickel Content onStress Corrosion CrackingStress Corrosion Cracking

Boiling 45% MgClBoiling 45% MgCl22

0

20

40

60

80

100

1 10 100 1000

Time to Failure, hrs

% N

icke

l No SCC

SCC 6% Mo SS6% Mo SSDuplex SSDuplex SS

Ni AlloysNi Alloys

HIGH CHLORIDE HIGH CHLORIDE WATERSWATERS

HIGH CHLORIDE HIGH CHLORIDE WATERSWATERS

How does external environment How does external environment affect process equipment?affect process equipment?

Marine Corrosion of C SteelMarine Corrosion of C SteelRelative Corrosion Rates* – Vary with Sea ConditionsRelative Corrosion Rates* – Vary with Sea Conditions

Atmospheric

Splash

Tidal

Submerged

Subsoil

5 mpy (0.13 mm/y)

25 mpy (0.64 mm/y)

*Protected Harbor

Uniform CorrosionUniform Corrosion

Effect of ChromiumEffect of Chromium

0

25

50

75

100

0 2 4 6 8 10 12 14 16 18

We

igh

t L

os

s, m

g. /

sq

. dm

.W

eig

ht

Lo

ss

, mg

. / s

q. d

m.

% Chromium% Chromium

250M Lot250M Lot44 Months44 Months

Alloy C in Marine AtmosphereAlloy C in Marine Atmosphere56 Years of Exposure56 Years of Exposure

Type 304 Fastener Type 304 Fastener InIn Marine Tide Marine Tide After 6 MonthsAfter 6 Months

Type 304 Fastener Type 304 Fastener AboveAbove Marine Tide Marine Tide After 6 Months After 6 Months

Crevice CorrosionCrevice Corrosion

Crevice Corrosion of Alloy 825Crevice Corrosion of Alloy 825Heat Exchanger Tubing – Shell Side Heat Exchanger Tubing – Shell Side

85 85° F° F, Aerated Seawater, Aerated Seawater

Crevice Corrosion of Alloy 625Crevice Corrosion of Alloy 625 Waterbox With Deaerated, Treated SeawaterWaterbox With Deaerated, Treated Seawater

165165°° F F 235235°° F F

165-235165-235°° F F

Crevice Corrosion of Alloy 825Crevice Corrosion of Alloy 825Heat Exchanger Tubesheet – Water Side Heat Exchanger Tubesheet – Water Side

225225°° F, Deaerated, Treated Seawater F, Deaerated, Treated Seawater

Tube to Tubesheet JointTube to Tubesheet Joint

Types Of Severe CrevicesTypes Of Severe Crevices

Stationary O Rings

Flange Face Under Gasket

Non-Metallic Connector

Tube to Tubesheet Joint

Corrosion of 90-10 Cu-NiCorrosion of 90-10 Cu-Niin Seawaterin Seawater

0

0.1

0.2

0.3

0.4

0.5

0.6

1 3 5 7 14

Time, Years

<1 fps

Tidal

3 fps

Co

rro

sio

n R

ate,

mp

y

Marine FoulingMarine Fouling18 Months in Quiet Seawater18 Months in Quiet Seawater

AluminumAluminumC SteelC Steel

Fouling of Titanium WaterboxFouling of Titanium Waterbox3 mo. Exposure3 mo. Exposure

Fouling of Titanium WaterboxFouling of Titanium Waterbox6 mo. Exposure6 mo. Exposure

Effect of ChlorinationEffect of Chlorination<1 fps Seawater Flow<1 fps Seawater Flow

0

10

20

30

0 1 4

Total Oxidant, ppm

Max

. Atta

ck, m

ils

90-10 Cu-Ni T-304

90-10 Cu-Ni Alloy90-10 Cu-Ni Alloy Fouling - Quiet SeawaterFouling - Quiet Seawater

3 Mo3 Mo 9 Mo9 Mo 18 Mo18 Mo

3 Yr3 Yr 4 Yr4 Yr 5 Yr5 Yr

90-10 Cu-Ni Intake Piping90-10 Cu-Ni Intake PipingDesalination PlantsDesalination Plants

90-10 Cu-Ni Alloy90-10 Cu-Ni AlloySeawater Piping SystemsSeawater Piping Systems

90-10 Cu-Ni Alloy90-10 Cu-Ni AlloySeawater Heat ExchangersSeawater Heat Exchangers

Pumps - ImpellersPumps - Impellers

Rouging of Stainless SteelsRouging of Stainless Steels

High Purity WaterHigh Purity Water

Water For Injection (WFI)Water For Injection (WFI)

Why Use Stainless Steels (316L) for Pharma & Biotech?

Good corrosion resistance and excellent batch Good corrosion resistance and excellent batch to batch cleanabilityto batch cleanability

Good structural properties for process Good structural properties for process equipmentequipment

Easily formed, fabricated and weldedEasily formed, fabricated and welded

What about Rouging?What about Rouging?What is Rouging?What is Rouging?

Rouging is a general term used to Rouging is a general term used to describe several species of describe several species of predominately iron oxide deposits on predominately iron oxide deposits on the wall of piping and vessels in high the wall of piping and vessels in high purity water systems.purity water systems.

Rouging is not New!Rouging is not New!

Rouging is not unique to the Rouging is not unique to the pharmaceutical and biotech pharmaceutical and biotech industries. Was recognized over 40 industries. Was recognized over 40 years ago with rouging of SS vessels years ago with rouging of SS vessels at Savannah River.at Savannah River.

Where is Rouge often FoundWhere is Rouge often Found

Water systems, usually high purity water and Water systems, usually high purity water and clean-steam systemsclean-steam systems

Distillation and clean-steam generating Distillation and clean-steam generating equipmentequipment

Rouge found on wall of vessels, piping and Rouge found on wall of vessels, piping and polymer gaskets (Teflonpolymer gaskets (Teflon®®) downstream of ) downstream of where originatedwhere originated

Is Rouge Harmful?Is Rouge Harmful?

No reports or evidence that rouging is No reports or evidence that rouging is precursor to a SS corrosion failure.precursor to a SS corrosion failure.

We are not in a position to comment on We are not in a position to comment on whether rouge is harmful to the product whether rouge is harmful to the product being produced. Common practice is to being produced. Common practice is to remove rouge.remove rouge.

Generally a loose powdery deposit, but can be Generally a loose powdery deposit, but can be tightly adherenttightly adherent

Hydrated or partially hydrated ferric oxide (FeHydrated or partially hydrated ferric oxide (Fe22OO33) )

or ferroso-ferric oxide (Feor ferroso-ferric oxide (Fe33OO44))

Usually occurs in high purity (0.5-1.0 µS/cm),Usually occurs in high purity (0.5-1.0 µS/cm),

high temperature water (60 – 100 high temperature water (60 – 100 C)C)

RougingRouging

Reddish brown rust color, but can range from Reddish brown rust color, but can range from orange to blue-black.orange to blue-black.

Origin is uncertain but generally thought to be Origin is uncertain but generally thought to be ions or colloids that are formed at one ions or colloids that are formed at one location and transported in the solution to location and transported in the solution to another where they are precipitated.another where they are precipitated.

Removed by acid cleaning in nitric, Removed by acid cleaning in nitric, phosphoric, citric, or oxalic acid.phosphoric, citric, or oxalic acid.

RougingRouging

Type 1 – Corrosion of Steel, Deposits DownstreamType 1 – Corrosion of Steel, Deposits Downstream

Pumps prime suspects – cavitation or erosion when velocity Pumps prime suspects – cavitation or erosion when velocity over ~ 100fps and higher temperaturesover ~ 100fps and higher temperatures

Delta ferrite in cast impellers may contribute by eroding easier Delta ferrite in cast impellers may contribute by eroding easier and higher iron contentand higher iron content

Type 2 – Corrosion Product of Stainless SteelType 2 – Corrosion Product of Stainless Steel

Type 3 – Corrosion Product of Stainless Steel in Steam Type 3 – Corrosion Product of Stainless Steel in Steam

Systems > 100 Systems > 100 CC

Rouging - TypesRouging - Types

Rouging of Stainless SteelsRouging of Stainless Steels

Rouging over 4 years inside electropolished Type 316L - column still used to produce ultra-pure water for pharmaceutical use

Rouging of Stainless SteelsRouging of Stainless Steels

De-rouging & PassivationDe-rouging & Passivation3 Steps3 Steps

Cleaning – detergent wash followed by Cleaning – detergent wash followed by thorough water rinsethorough water rinse

De-rouging chemical treatmentDe-rouging chemical treatment

Passivation followed by thorough water rinsePassivation followed by thorough water rinse

Electrochemical ColoringElectrochemical ColoringProprietary electrochemical processes – Proprietary electrochemical processes –

invented in 1972 by Inco, further developed invented in 1972 by Inco, further developed in Japanin Japan

• Interference between the Interference between the light beams refracted from light beams refracted from the substrate and the the substrate and the surface of the oxide film surface of the oxide film creates colorcreates color

• Appearance and colorAppearance and color vary vary with immersion time and with immersion time and surface finishsurface finish

IncidentIncidentlightlight ColorColor

OxideOxide

Experience Music ProjectExperience Music Project

SummarySummary

Discussed Scaling and CorrosionDiscussed Scaling and Corrosion

Described Effects of VelocityDescribed Effects of Velocity

Reviewed Biological EffectsReviewed Biological Effects

Discussed ChloridesDiscussed Chlorides

Summarized Rouging of SSSummarized Rouging of SS

Questions ?Questions ?