WI2318a API Research on DCB testing of C110

DCB Testing of C-110 in Standard and Mild Conditions For Determination of Klimit

WI TARGETS

1/ Define correct procedure of DCB testing

2/ Define acceptance criteria for compliance aspect (WI2348)

3/ Define threshold of K1SSC for C110 in mild sour environment to resolve informative SR39

Reminder from January 2012 meeting

WI2318a API Research on DCB testing of C110

• New Plan for 2013-2014 study at OMNI (budget 180 kUSD)

5 commercial pipes donated from 3 vendors

STEP 0

Total 8

STEP0

STEP 1

Total 120STEP1

STEP 2

Total 24STEP2

STEP 3 T° effect

Total 24STEP3

STEP 4

Total 24STEP3

sum 192

H1 2013

2013

HRC effect

decision at june 2013 meeting

decision at june 2013 meeting

completed by june 2013

Fatigue precracking effect

decision at jan 2014 meeting

comparison full NACE vs Mild sour sln

compliance for DCB with EDM geometry SCHEDULE

CANCELLED

WI2318a API Research on DCB testing of C110

DCB Testing

New specimen design (crack tip matches base of chevron).

Careful preparation & HRC testing (6 readings per specimen).

3 arm displacements with 4 specimens per displacement.

New bath time for mild tests (17 days in bath, no 3-day hold).

Each group of 4 divided between two tanks.

H2S analyses:

Standard: Tank 1: 2812 ppm Tank 2: 2796 ppm

Mild: Tank 1: 183 ppm Tank 2: 189 ppm

DCB Testing (cont.)

Mild test liftoffs all within 2 hours.

Tests inspected for validity:

Short or No Crack 2 2

Edge Cracks 2 17

Non-Planar 0 1

Defect Mild Standard

# of Invalid Tests

Avg. temperatures of all 4 vessels within 0.3 °F of standard 75 °F.

Standard Conditions, Pipe AveragesStd. 0.020” (0.51mm) Arm Displacement

24 25 26 27 28 29 3010

15

20

25

30

35

40

45

50

55

60

HRC

KIs

sc

, k

si-

in0

.5

API Minimum

Mild Conditions, Pipe AveragesAPI Std. 0.035” (0.89mm) Arm Displacement

24 25 26 27 28 29 3010

15

20

25

30

35

40

45

50

55

60

HRC

KIs

sc

, k

si-

in0

.5

24 25 26 27 28 29 3010

15

20

25

30

35

40

45

50

55

60

HRC

KIs

sc

, k

si-

in0

.5

Mild

Standard

Mild & Standard Conditions, Pipe Averages

API Minimum

Rank

Standard Mild

B

C

D

A

E

A

D

B

E

C

WI2318a API Research on DCB testing of C110

WI2318a API Research on DCB testing of C110

Action for January 2014 review

Need to implement some (20/120) retests from step1

Activate step2 for HRC effect from ring E & step3 for T° effect

WI2318a API Research on DCB testing of C110

• New Plan for 2013-2014 study at OMNI (budget 180 kUSD)

5 commercial pipes donated from 3 vendors

STEP 0

Total 8

STEP0

STEP 1

Total 120STEP1

STEP 2

Total 24STEP2

STEP 3 T° effect

Total 24STEP3

STEP 4

Total 24STEP3

sum 192

H1 2013

2013

HRC effect

decision at june 2013 meeting

decision at june 2013 meeting

completed by june 2013

Fatigue precracking effect

decision at jan 2014 meeting

comparison full NACE vs Mild sour sln

compliance for DCB with EDM geometry SCHEDULE

CANCELLED

Study on C110 Kissc & Klimit in Weak H2S Solutions

USS work from Jan 2012

comprehensive presentation “Studies on C110 Critical Stress Intensity Factor (K1ssc) in Weak H2S Solution” illustrating in particular the non linear relation of K1ssc vs H2S partial pressure and same for K1ssc vs arm displacement within various mild environments.

+ update june 2013K1ssc & Klimit = a ln [H2S] +bHigh [H2S] => solution is governingLow [H2S] => microstructure is governing

15United States Steel Corporation

DCB Data C110 -Heat #2

16United States Steel Corporation

K limit in 7.0% H2S Solution NACE A sln

y = 0.164x + 25.914R² = 0.6884

y = 0.2752x + 22.841R² = 0.6489

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

50.0

55.0

10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0

K ISS

C(k

si in

2 )

KIapplied (ksi in2)

7% H2S

Heat 1 Heat 2

32 ksi in-2

31 ksi in-2

K limit in 99.5% H2S Solution NACE A sln

17

y = 0.1035x + 21.629R² = 0.5428

y = 0.1136x + 21.697R² = 0.6891

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

50.0

55.0

10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0

K ISS

C(k

si in

2 )

KIapplied (ksi in2)

99.5% H2S

Heat 1 Heat 2

24 ksi in-2

24.7 ksi in-2

Klimit In Various H2S Solutions (NACE A sln)

18

y = -2.696ln(x) + 36.342R² = 0.9533

y = -2.403ln(x) + 35.314R² = 0.7859

15.0

20.0

25.0

30.0

35.0

0.0 20.0 40.0 60.0 80.0 100.0 120.0

K lim

it(k

si in

2 )

H2S Concentration (%)

Heat 1 Heat 2

K limit approximately follows a power law relationship with H2S concentration, which is similar to the trend of KISSC as seen in Slides 7 & 8