Anti-Corrosion Steel for Pitting corrosion on COTs of crude oil

1

AntiAnti--Corrosion Steel forCorrosion Steel forPitting corrosion on COTsPitting corrosion on COTs

of crude oil carrierof crude oil carrier

The NSGP-1Nippon Steel’s Green Protect-1

2

The Studies on COT Corrosion in Japan2000 2002 2004 20061998 2000 2002 2004 20061998

Shift to Double Hull Tanker1990~

1999~2002 Panel SR242 Investigation(The Shipbuilding Research Association of Japan)

2002~

2004~NSGP-1 Field Test on actual Vessels

Anti- corrosion steelLaboratory Test

Scientific Research & understandingof the corrosion phenomena

(Over 10 VLCC s)Basis for Anti-corrosion SteelCorrosion test method

NSGP-1

3

↑Inner Bottom

Inert Gas H2O H2S CO2

Crude Oil

Drain Water

Upper Deck PlateUpper Deck PlateUniform CorrosionUniform Corrosion

Inner Bottom PlateInner Bottom PlatePitting CorrosionPitting Corrosion

Upper Deck↓

Corrosion problems on COT of crude oil carriers

COT corrosion ・Upp.DK uniform corrosion・Pitting on bottom plate

4

Observed Pits on COT bottom plates

・Very Deep : Max. abt.10mm/2.5years・Periodical Repair is Essential

SRSR--242 Result242 Result

5

Corrosion on COT Bottom= Localized Corrosion

0

1

2

3

4

5

6

7

8

9

10

11

12

DH-1 DH-2 DH-3 DH-4 DH-5

Max

. Pit

Dept

h m

m

・Very high frequencyPitting on Bottom ・Very Deep : Max. abt.10mm/2.5years

・Periodical Repair is Essential !

0

200

400

600

800

1000

1200

1400

1P 2P 3P 4P 5P 1C 2C 3C 4C 5C 1S 2S 3S 4S 5S

COT Position

Pits

Coun

t ove

r 4mm

Dep

th

DH1 2.5yDH1 5.0yDH2 2.5y


No Need to Repair

Paint Repair

Weld Repair

6

How does the pitting corrosion start?

7

Observed insulating resistance of oil coating and tar epoxy painting

Oil coating exists inside of COTOil coating shows high insulating resistance equal to T/E

0

100

200

300

400

500

600

Oil Coating Tar Epoxy

Resis

tance

kΩ･c

Oil coat T/E paint

SensorSensorRSTRST®®

Measurement of resistance


8

Cause of oil coating defect-1 Change of oil coating resistance by wetting.

Wetting decreases insulating resistance of oil coat

0

100

200

300

400

500

600

Befor AfterWetting effect

Resis

tance

k Ω･c

m2

SensorSensor

Distilled WaterDistilled Water


9

COT No Na T-Fe Fe3+ Cl- SO42- Mg2+ pH H2S

DH-1 13600 2 2 42500 14 ND 7.0 NDDH-3 1S 40000 42 11 48000 1470 ND 7.2DH-3 2P 40000 2.5 1 54000 1350 ND 7.5

Chemical analysis of water sampled from actual COT bottom

Significant quantity of water exists on COT bottomHigh concentration of NaCl solutionNot seawater but Brine from Oil Well

↓Brine damages oil coating resulting pitting CorrosionBrine damages oil coating resulting pitting Corrosion(Existence of Brine : Not depends on crude oil a/o route)

Cause of oil coating defect-1 Change of oil coating resistance by wetting.


10

COW damages oil coating largelyCOW shadow area is free from corrosion

0

500

1000

1500

2000

2500

3000

No COW 1COW 2COW

Number of COW

Res

ista

nce

k Ω･c

!!COW#1

COW#2

Apparent corrosion!

Cause of oil coating defect-2 Change of oil coating resistance by removal.


No corrosion

11

Short Summary - 1

• Oil coating layer exists inside of COT

• Oil coating layer provides protective effect to corrosion

• Brine a/o COW damages oil coating protective effect

• Pitting starts at the damaged oil coating area

12

How much is the pitting corrosion rate?

13

: Pits over 4mm at 1st inspection (repaired) : Pits less than 2mmless than 2mm at 1st1st inspection (NOT repairedNOT repaired)

: Pits over 4mm at 2nd inspection (repaired)Old pits() did not grow!

New pits() were observed at different points.↓

Pitting growth terminated at the 1st Dock inspection→ Corrosion rate = Pit Depth/Dock Interval

1C

Change of pitting location in plural inspectionsSRSR--242 Result242 Result

14

1P

Change of pitting location in plural inspection-2

: Pits over 4mm at 1st inspection (repaired) : Pits less than 2mmless than 2mm at 1st1st inspection (NOT repairedNOT repaired)

: Pits over 4mm at 2nd inspection (repaired)Old pits() did not grow!

New pits() appear at different points.


15

f

0 xX1 X2X3X15

X1~X15 : Max pit depthin each COT

f

0 xX1 X2X3X15

f

0 x

f

0 xX1 X2X3X15

X1~X15 : Max pit depthin each COT

Statistical analysis of localized corrosion

Maximum Value DistributionF(x) ~ exp(-exp(-[x-λ]/α))Extreme Value Distribution

Depth of Pit

Corrosion depth is not uniform

Statistical analysis enables to illustrate and describe,･Quantitative behavior of pitting corrosion･Max. corrosion rate (depth) for 15 COT･Ave. corrosion rate

F(x) x2x1

x3x15

15COT

Max. C.R.

50%

Av. C.R.

F(x) x2x1

x3x15

15COT

Max. C.R.

50%

Av. C.R.

16

･Maximum pitting rate follows statistical distribution･Ship age based corrosion rate : Distribution varies ship by ship →Irrational･Dock Interval Corrosion rate : Same & identical distribution

→ Rational (Corrosion environment cannot differ from ship to ship largely)

1.011.051.111.251.431.6722.53.335

10

202533.350

100

0 1 2 3 4Corrosion Rate mm/year

Ret

urn

Perio

d T

VLD-12.4Years

VLS-12.5Years

VLS-22.5Years

F

99%

98%97%96%95%

90%

80%70%60%50%40%30%20%10%5%1%

0 1 2 3 4Corrosion Rate mm/year

Cum

ulat

ive

Freq

uenc

y F

VLS-17Years

VLD-12.4years

VLS-25years

C.R=Depth/Dock IntervalC.R=Depth/Ship Age

Statistical Distribution of max. pitting corrosion rate (by Statistical extreme value analysis)

17

Brine : NaCl ~10wt.%

Corrosion condition would be reset after Dock inspection→Pitting growth stops at dock cleaning

(1) Under servicing condition

(2) Dock cleaning for inspection

(3) Re-Start of service

(4) Nuclear of new pit

Sludge & Corrosion products

Oil coating

Cleaned Steel Surface = No oil coat

Oil coating ,Sludge & Corrosion productsare cleaned and dried for inspection

Cleaned and dried pits are re-coated by new crude oil

New oil coating = Resetting insulating condition

defect

New defect in oil coating =Nucleation of pitting

New defect : by COW, Brine …..

Discussion on pit growth

Brine : NaCl ~10wt.%


18

Pit Growth Stops at a dock(tank cleaning)

Pitting Stops

Pit D

epth

↑Dock Inspection Ship Age

New Pitting starts at new location

Important Basis for Anti-Corrosion Steel

19

Short Summary - 2

• Pitting corrosion rate follows statistical distribution

• Pitting growth duration is dock interval

• Pitting stops at a dock (COT cleaning)

20

What is the pitting environment?

21

Pitting progresses isotropically

keeping constant depth/diameter ratio

If pitting progresses by Galvanic Action…

Irrational to the fact

Shape of Pits

Depth is in linear relation with diameter

0

5

10

15

20

25

30

35

40

45

0 2 4 6 8 10 12Depth mm

Dia

met

er m

m

VLS-B

VLD

VLD-D

VLS-F

・Pitting progresses isotropically with large corrosion rate : abt. 10mm/2.5year・This process hard to think as a result of Galvanic corrosion・Corrosion Environment inside of pit is supposed to be highly aggressive


22

An example of observed pH inside of pitspH : Lower than 1.5 → Strong Acid environment

Actual Vessel

pH of PIT inside: <1.5

→→Unfavorable for MIC ((SRB SRB active pH : 6~9active pH : 6~9))


23

Max. pitting rate : Very high abt. 3mm/y in actual vessel→ can be explained under strong acid corrosion environment → meets the observed fact : pH inside of pit lower than 1.5

Pitting can be explained as corrosion in strong acid environment

0

1

2

3

4

5

6

7

024681012pH

Corro

sion R

ate m

m/ye

arOxygen consumption ← → H2 evolution

Conventional Steel

Observed pH and Max. corrosion rate

24

Corrosion growth process inside of Pit

【1st Step】Corrosion starts

pH~70.2mm/y

【2nd Step】4< pH <7

pH goes down ~40.2mm/y

【3rd Step】Main corrosion process

pH goes down lower than1.52~4mm/y

Crude Oil

Bottom Plate

Oil Coat DefectBrine (NaCl 10%)

Oil CoatFe2+

↑Fe

Crude Oil

Oil Coat

H+HH++

pH<1.5pH<1.5pH<1.5

Cl-Crude Oil

Oil CoatCl-

Fe2+ + 2H2O → 2H+ + Fe(OH)2

pH>4pH>4pH>4

0

1

2

3

4

5

6

7

024681012pH

Corro

sion R

ate m

m/ye

ar

【2nd Step】

【3rd Step】

【1st Step】

Conventional Steel

Fe2+ + 2H2O → 2H+ + Fe(OH)2

High conc. [Cl-] in Brine

↑Fe (Corrosion)

Cl- ← Balance → H+

in High conc.

Low pH inside of pit↓

25

Short Summary - 3

• Corrosion environment inside of pit is Strong Acid

• pH lower than 1.5 inside of pit

26

Development target and result

27

Established Corrosion test condition simulating environment inside of pit

Beaker

SpecimenTest solution

NoticeNaCl 10 mass%

pH Lower than 1.5 Adjust by HCl

Amount 20cc/.cm2 or more

Change Every 24 to 48 hoursAir open

30

Size 40mm x 50mm x t t: less than 4mml

Surface #600 emery paper Follow JIS G0591

repeat n=3 or more

144hours

Dipping specimen Follow JIS G0591Immersion

Gas

Temperature

Condition

Solution

Specimen

Duration

28

0

1

2

3

4

5

6

7

8

0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5pH

Corro

sion R

ate m

m/ye

ar

← Conventional Steel

NaCl 10wt.%30

Air OpenStagnant

n=3

NSGP-1 provides superior corrosion resistance (NaCl 10wt.% pH less than 1.5)

Conventional pH=1

NSGP-1 pH=1NSGP-1NSGPNSGP--11

29

Outline of the NSGP-1Newly Developed Anti-corrosion Steel for VLCC COT

A typical example of chemical analysis （mass%)

NSGP-1 established high corrosion resistancewith Least Micro-alloy Elements & ControlNegligible difference to conventional steel

↓No galvanic action with conventional steels & welds

No effect to Physical Properties

C Si Mn P S Al Ti CeqNSGP-1 0.124 0.331

AH32 0.140 0.20 1.09 0.018 0.006 0.031 0.014 0.322IACS Standard ≦ 0.18 ≦ 0.5 0.9～1.6 ≦ 0.035 ≦ 0.035 ≧ 0.02 ≦ 0.02 ≦ 0.36

meets IACS Standard (including all ally elements)

The Chemical composition meets the IACS rules

30

Short Summary - 4

• Developed corrosion test NaCl 10wt.% pH lower than 1.5

• Successful development of NSGP-1 has completed bearing high corrosion resistance with Least Micro-Alloy Elements

(Negligible difference to conventional steel)

31

Property of NSGP-1

･Corrosion Property ･Mechanical Property･Weldability

32

Welding Condition for Property Tests

1000 A, 35 V, electrode speed: 35 m/min heat input: 102.3 kJ/cmPass conditions

50˚ (25˚ each side) root gap :2 mmGrove shapeFAB-1 Metal powder PR2Backing platePF152EFluxUS36(4.8mmφ)Welding Rod

33

0

1

2

3

4

5

6

7

8

0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5pH

Corro

sion R

ate m

m/ye

ar


NaCl 10wt.%30

Air OpenStagnant

n=3

NSGP-1 provides superior corrosion resistance (NaCl 10wt.% pH less than 1.5)

Conventional pH=1

NSGP-1 pH=1NSGP-1NSGPNSGP--11

34

NSGP-1 shows NO preferential corrosion around weld (pH=0.8, 336hrs)

NSGP ｜ Weld Metal ｜NSGP

NSGP-1

１００μm

35

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

Matrix Weld

COrro

sion R

ate m

m/ye

ar

ConventionalNSGP-1

NSGP-1 shows equivalent corrosion property toconventional steel in water ballast tank environment

・Artificial Sea Water・40 Stagnant・4 weeks

← Weld →|← MatrixMatrix →|

NSGP-1

No Galvanic action between Weld and Matrix

36

NSGP-1 provides good weldabilityY-groove cracking test

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 50 100

Pre-heat Temperature

Crac

k Rat

io %

SurfaceCross sectionRoot

No Crack

0

50

100

150

200

250

300

350

0 20 40 60

Bead Length (mm)

Maxim

um H

ardn

ess(

Hv 1

0kgf

)

37

NSGP-1 provides good fatigue property

100

1000

Stre

ss R

egion

, Δσ(

N/mm

2 )

NS-GP1

YP32,36HT(5 Joints)

Butt Weld Joint (Flat Position)

100

1000

10000 100000 1000000 10000000Number of Cycles to Failure

Stre

ss R

egion

, Δσ(

N/mm

2 )

NS-GP1YP36HT(3 Joints)

Base Metal

10

100

1000

10000 100000 1000000 10000000Number of Cycles to Failure

Stre

ss R

egion

, Δσ(

N/mm

2 )NS-GP1

YP32,36HT(5 Joints)

Fillet Weld T-joint

38

NSGP-1 shows good toughness

0

50

100

150

200

250

300

WeldMetal

Fusion Line

HAZ 1mm

HAZ 3mm

HAZ 5mm

Notch Position

Abso

rbed

Ene

rgy a

t 20

vE20

(J) : Center : 1mm below surface

Standard ≧ 34J

0

50

100

150

200

250

300

WeldMetal

Fusion Line

HAZ 1mm

HAZ 3mm

HAZ 5mm

Notch Position

Abso

rbed

Ene

rgy a

t 20

vE20


Standard ≧ 34J

0

50

100

150

200

250

300

WeldMetal

Fusion Line

HAZ 1mm

HAZ 3mm

HAZ 5mm

Notch Position

Abso

rbed

Ene

rgy a

t 20

vE20


Standard ≧ 34J

0

50

100

150

200

250

300

WeldMetal

Fusion Line

HAZ 1mm

HAZ 3mm

HAZ 5mm

Notch Position

Abso

rbed

Ene

rgy a

t 20

vE20


Standard ≧ 34J

FAB, L direction

Welding Method Shape of groove Heat Input(kJ/cm)

Flux(PFI-52E) Backing Metal(FAB-1)

Welding Material

Table Welding Condition

125Wire(US-36ƒ³6.4)FAB V

0

50

100

150

200

250

300

WeldMetal

Fusion Line

HAZ 1mm

HAZ 3mm

HAZ 5mm

Notch Position

Abso

rbed

Ene

rgy a

t 20

vE20


0

50

100

150

200

250

300

WeldMetal

Fusion Line

HAZ 1mm

HAZ 3mm

HAZ 5mm

Notch Position

Abso

rbed

Ene

rgy a

t 20

vE20


Standard ≧ 34J

0

50

100

150

200

250

300

WeldMetal

Fusion Line

HAZ 1mm

HAZ 3mm

HAZ 5mm

Notch Position

Abso

rbed

Ene

rgy a

t 20

vE20


0

50

100

150

200

250

300

WeldMetal

Fusion Line

HAZ 1mm

HAZ 3mm

HAZ 5mm

Notch Position

Abso

rbed

Ene

rgy a

t 20

vE20


Standard ≧ 34J

0

50

100

150

200

250

300

WeldMetal

Fusion Line

HAZ 1mm

HAZ 3mm

HAZ 5mm

Notch Position

Abso

rbed

Ene

rgy a

t 20

vE20


0

50

100

150

200

250

300

WeldMetal

Fusion Line

HAZ 1mm

HAZ 3mm

HAZ 5mm

Notch Position

Abso

rbed

Ene

rgy a

t 20

vE20


Standard ≧ 34J

0

50

100

150

200

250

300

WeldMetal

Fusion Line

HAZ 1mm

HAZ 3mm

HAZ 5mm

Notch Position

Abso

rbed

Ene

rgy a

t 20

vE20


0

50

100

150

200

250

300

WeldMetal

Fusion Line

HAZ 1mm

HAZ 3mm

HAZ 5mm

Notch Position

Abso

rbed

Ene

rgy a

t 20

vE20


Standard ≧ 34J

FAB, L direction



Welding Material





Welding Material



39

Applied Result of NSGP-1to actual COTs of VLCC

40

NSGP-1 has been applied to actual vessel(All COT bottom have been built with NSGP-1)

NSGPNSGP--11 has been applied to actual vessel(All COT bottom have been built with NSGP-1)

1P

1C

1S

2P

2C

2S

3P

3C

3S

4P

4C

4S

5P

5C

5S

FWD

Ship TAKAMINE (Built by Mitsubishi Heavy Industry)Construction completed with no problem

Applied to all COTs’ bottom platesFor #3 and #4 COTs applied without painting

1st Dock inspection : at 2year 3 month after launching(3P,3S: inspected onboard at 1year9month)

NSGP-1 without Painting

NSGP-1 with Tar-Epoxy painting

41

Conventional

Conventional

NSGP® -1

Conventional

Conventional

NSGP® -1NSGP® -1

NSGP® -1

NSGPNSGP--11 No pit around Drain Hole**Drain Hole : Pits are frequently observed on conventional steel

No Pit observed Frequent deep Pits

42

Weld Line : NO pit marks

NSGP® -1NSGP® -1

NSGPNSGP--11 No Pit around Weld**Weld : No pit has been observed also on conventional steel

43

0 0 0 0 0 00

200

400

600

800

1000

1200

1400

3P 3C 3S 4P 4C 4SCOT Position

Pits

Coun

t ove

r 4mm

Dep

thAt the 1st dock : 2.25 years after building

NSGPNSGP--11 No pit over 4mm depthNo Need to repair, she docked out smoothly.

NSGP® -1NSGP® -1

NSGP-1 brought about actual benefit in actual field for the 1st time

44

Detailed survey on NSGP-1

Finding shallow pits 2 to 4mm depthand

It’s analysis

45

NSGPNSGP--11 Only shallow pits less than 3mm were observed*Repair criteria above 4mm:Paint Repair Above 7mm:Weld Repair

NS-GP120mm NS-GP120mm20mm

↑Pit

←Pit

Depth: 2.8mm Depth: 6.3mm

20mm Conventional20mm20mm Conventional

46

NSGPNSGP--11 Only shallow pits with very low frequency*Repair criteria above 4mm:Paint Repair Above 7mm:Weld Repair

7 7 7 20 4 270

200

400

600

800

1000

1200

1400


Pits

Coun

t ove

r 2mm

less

than

4mm

Dep

th

At the 1st Dock( 2.25years after building)

COT built by NS- GP1 without tar epxy painting

NO NEED TO REPAIR

0

2

4

6

8

10

12


Obse

rved M

ax pi

t dep

thmm

/at 1s

t Doc

k

COT built by NS-GP1without tar epxy painting

No Need to Repair


0

2

4

6

8

10

12


Obse

rved M

ax pi

t dep

thmm

/at 1s

t Doc

k

COT built by NS-GP1without tar epxy painting

No Need to Repair


47

1%5%

10%20%30%40%50%60%70%

80%

90%

95%96%97%98%

99% 100

50352520← 15COT10

5

32.521.61.41.21.11.051.01

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5

Corrosion Rate mm/year

Cumu

lative

Fre

quen

cy F

Retu

ren

Perio

d T

No Repair Repair by Paint Repair by Weld

NSGP-1 Conventional Steels

← 4mm/2.5years

Estimation of Maximum depth

Estimated Maximum Pitting rate & Depth for 15COT : Less than 4mm/2.5y

←AlmostEqualGradient

48

Precise Estimation of pH inside of pit : lower than 0.85Test condition: NaCl 10wt.% pH lower than 0.85

Target corrosion rate : Less than 0.9mm/year

Proposal onDefinition and test method

for anti-corrosion steel

49

Precise estimation of pH inside of PitLower than 0.85

Ship Estimated pHA 1.11B 1.16C 0.93D 0.85E 1.07F 0.94

Ship Max depthmm/2.5years

Max Corrosion Ratemm/year

A 7.50 3.00B 7.06 2.82C 9.51 3.80D 10.57 4.23E 7.90 3.16F 9.40 3.76

A B

CD

EF

0

1

2

3

4

5

6

7

8

0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5pH

Corro

sion R

ate m

m/ye

ar

↓ Conventional Steel

Laboratory EvaluationNaCl 10wt.%

30Air OpenStagnant

n=3

50

Established corrosion test for anti-corrosion steelReproducing environment at inside of pits

Beaker


Notice

NaCl 10 mass%

pH 0.85 Adjust by HCl



30

Size 40mm x 50mm x t 　t: less than 4mml


repeat n=3 or more

144hours


Gas

Temperature

Condition

Solution

Specimen

DurationBeaker


Beaker


Notice

NaCl 10 mass%

pH 0.85 Adjust by HCl



30

Size 40mm x 50mm x t 　t: less than 4mml


repeat n=3 or more

144hours


Gas

Temperature

Condition

Solution

Specimen

Duration

51

99%

98%

97%96%95%

90%

80%

70%60%50%40%30%20%10%5%

1% 1.01

1.051.11.21.41.6

← 2 Average λ2.53

5

10← 15 COT20253550

100

0 0.5 1 1.5 2 2.5 3Corrosion Rate mm/year

Cumu

lative

Fre

quen

cy F

Retur

n Per

iod T

NSNS--GP1GP1

0.9mm/y

Criterion forAnti-corrosion Steel

Max Corrosion rate for4mm depth for 2.5years in 15COT

Criterion of corrosion rate in Laboratory testfor Repair-Free at 2.5years dock interval

Criterion : less than 0.9mm/year in laboratory test

Need to repair

← Corresponds toLaboratorytest evaluation

← Corresponds toOnboardMax. Depth

52

0

1

2

3

4

5

6

7

8

0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5pH

Corro

sion R

ate m

m/ye

ar


NaCl 10wt.%30

Air OpenStagnant

n=3

Proposal to anti-corrosion steel definitionbeing Repair-Free at 2.5years dock interval

(NaCl 10wt.% pH less than 0.85)

NSGP-1NSGPNSGP--11

↓ Less than 0.9mm/yearAcceptable

asAnti-Corrosion Steel

53

Proposal for Maximum utilization of NSGP-1Basic facts and judgment

1. NSGP-1 protects bottom plate of COT from pitting by reducing the depth to least level . (less than 3 mm/2.5y)

2. Specification for pit depth to be repaired: Over 4mm/2.5 years. (judgment by NYK)

↓3. COT made of NSGP-1

: Repair work is absolutely unnecessary.

54

Proposal for Maximum utilization of NSGP-1Adjusting Dock interval to 2.5 years enables Repair Free

0

2

4

6

8

10

12

0 5 10 15 20 25 30 35Ship Age / years

Corro

sion D

epth

/ mm

No need for maintenance during a whole ship life with NS-GP1

Observed Results

No ne

ed to

Re

pair

Pit Growth Terminatesat Dock inspection

[Found by SR242]

Observed Max. Corrosion Depthwith NS-GP1

Less than 4mm

0

2

4

6

8

10

12

0 5 10 15 20 25 30 35Ship Age / years

Corro

sion D

epth

/ mm

Repair Free during a whole ship life with NSGP-1

Related Facts

No ne

ed to

Re

pair

Pit Growth Stopsat Dock inspection

Observed Max. Corrosion Depthwith NS-GP1

Less than 3mm

NSGP-1 +2.5years dock interval = Repair-FreeDock Inspection

55

Conclusion on NSGP-1Conclusion on NSGPConclusion on NSGP--111）Confirmed excellent corrosion resistance in actual VLCC

2) Potential for repair free for whole ship life

- Small pitting corrosion rate : Less than 3mm/2.5years- NSGP-1 + 2.5years dock interval = Repair FREE

(Pit growth stops at dock cleaning)

2）Excellent mechanical properties and weldability(Superior than conventional steels)

3）No dependence on the workmanship or the working condition(Completely different from painting)

11））Confirmed excellent corrosion resistance in actual VLCCConfirmed excellent corrosion resistance in actual VLCC

2) Potential for repair free for whole ship life2) Potential for repair free for whole ship life

-- Small pitting corrosion Small pitting corrosion raterate : Less than 3mm/2.5years: Less than 3mm/2.5years-- NSGPNSGP--1 + 2.5years dock interval = Repair FREE1 + 2.5years dock interval = Repair FREE

(Pit growth stops at dock cleaning) (Pit growth stops at dock cleaning)

22））Excellent mechanical properties and Excellent mechanical properties and weldabilityweldability(Superior than conventional steels)(Superior than conventional steels)

33））No dependence on the workmanship or the working conditionNo dependence on the workmanship or the working condition(Completely different from painting)(Completely different from painting)

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Practical Advantages of the NSGP-1 for Ship OwnerPractical Advantages of the NSGPPractical Advantages of the NSGP--1 for Ship Owner1 for Ship Owner

By using NSGP-1 for COT of crude oil carriers, • Great improvement in the safety and reliability of marine

vessels and in the protection of the global environment• Anti-corrosion coating becomes unnecessary, as do

coating agents and volatile organic compounds.• No need for paint repair and plate replacement.

↓NYK decided to use the NSGP-1 on all new tankers, including 5 VLCCs currently on order.

By using NSGPBy using NSGP--1 for COT of crude oil carriers, 1 for COT of crude oil carriers, •• Great improvement in the safety and reliability of marine Great improvement in the safety and reliability of marine

vessels and invessels and in the protection of the global environmentthe protection of the global environment•• AntiAnti--corrosion coating becomes unnecessary, as do corrosion coating becomes unnecessary, as do

coating agents and volatile organic compounds.coating agents and volatile organic compounds.•• No need for paint repair and plate replacement.No need for paint repair and plate replacement.

↓↓NYK decided to use the NSGPNYK decided to use the NSGP--1 on all new tankers, 1 on all new tankers, including 5 including 5 VLCCsVLCCs currently on order.currently on order.

Documents

Anti-Corrosion Steel for Pitting corrosion on COTs of crude oil