1. Grain growth in Line Pipe Steels
Solutions for critical materials under extreme conditions
Grain growth in Line Pipe Steels
Written by: Walter Antonio Tichauer
Advisor: Ernst Gamsjäger, assoz.Prof. Dipl.-Ing. Dr.mont.

2. Contents -Pipelines for oil and gas transport
Pipeline engineering
What properties are we looking for?
Do we REALLY need materials with higher material strengths?
-In situ grain size measurements
LUT
HT-LSCM
Average grain size & Distribution
MEASUREMENTS
RESULTS
-Comparison of both techniques
-Conclusions

3. Contents -Pipelines for oil and gas transport
Pipeline engineering
What properties are we looking for?
Do we REALLY need materials with higher material strengths?
-In situ grain size measurements
LUT
HT-LSCM
Average grain size & Distribution
MEASUREMENTS
RESULTS
-Comparison of both techniques
-Conclusions

4. -Pipeline engineering
Properties of different materials
Machining of materials
Microstructure-properties relationship
Sc… Strength of the material
SF… Safety factor
L… Loads
B… Back ups

5. -Pipeline engineering
Properties of different materials
Machining of materials
Microstructure-properties relationship ΔT
Gas composition
Longitudinal ground profile
Q → n → Dp

6. What properties are we looking for?
PROPERTIES WE ARE LOOKING FOR:
High ductility
High strength
Excellent weldability
How can we achieve this?
David and Goliath

7. Do we REALLY need materials with higher material strengths?

8. Do we REALLY need materials with higher material strengths?
YES

9. Contents -Pipelines for oil and gas transport
Pipeline engineering
What properties are we looking for?
Do we REALLY need materials with higher material strengths?
-In situ grain size measurements
LUT
HT-LSCM
Average grain size & Distribution
MEASUREMENTS
RESULTS
-Comparison of both techniques
-Conclusions

10. Contents -Pipelines for oil and gas transport
Pipeline engineering
What properties are we looking for?
Do we REALLY need materials with higher material strengths?
-In situ grain size measurements
LUT
HT-LSCM
Average grain size & Distribution
MEASUREMENTS
RESULTS
-Comparison of both techniques
-Conclusions

11. Laser Ultrasonics Technique (LUT) [1]
Provided by Professor Militzer M.

12. Contents -Pipelines for oil and gas transport
Pipeline engineering
What properties are we looking for?
Do we REALLY need materials with higher material strengths?
-In situ grain size measurements
LUT
HT-LSCM
Average grain size & Distribution
MEASUREMENTS
RESULTS
-Comparison of both techniques
-Conclusions

13. High Temperature Laser Scanning Confocal Microscopy (HT-LSCM)

14. Video Grain growth

15. Average grain size & Grain size distribution MEASUREMENTS of a sample heated up to 1050 °C

16. Average grain size & Grain size distribution MEASUREMENTS of a sample heated up to 1150 °C

17. Average grain size & Grain size distribution MEASUREMENTS of a sample heated up to 1250 °C

18. Average grain size RESULTS
Conditions to t1
Conditions to t2
Sample
t1 [s]
number of grains
d [µm]
t2 [s]
1050 °C
180.07
406
*14.4
242.78
337
17.4
1150 °C
94.84
267
21.6
257.28
*189
30.1
1250 °C
 66.23
363
*15.8
270.91
*218
53.1
*[2]

19. Grain size distribution RESULTS of a sample heated up to 1050 °C

20. Grain size distribution RESULTS of a sample heated up to 1150 °C

21. Grain size distribution RESULTS of a sample heated up to 1250 °C

22. Contents -Pipelines for oil and gas transport
Pipeline engineering
What properties are we looking for?
Do we REALLY need materials with higher material strengths?
-In situ grain size measurements
LUT
HT-LSCM
Average grain size & Distribution
MEASUREMENTS
RESULTS
-Comparison of both techniques
-Conclusions

23. Comparison of LUT and HT-LSCM average grain size measurements

24. Comparison of LUT and HT-LSCM average grain size measurements

25. Contents -Pipelines for oil and gas transport
Pipeline engineering
What properties are we looking for?
Do we REALLY need materials with higher material strengths?
-In situ grain size measurements
LUT
HT-LSCM
Average grain size & Distribution
MEASUREMENTS
RESULTS
-Comparison of both techniques
-Conclusions

26. Conclusions
-During phases of high DT changes, LUT complements HT-LSCM.
-HT-LSCM will be REQUIRED
if a multimodal distribution is expected
if the grain size distribution is unknown

27. References
[1] Militzer M, Maalekian M, Radis R, Poole W J, Moreau A. In situ measurement and modeling of austenite grain growth in a Ti/Nb microaalloyed steel Acta Materialia 60 (2012) [2] ASTM International. Standard Test Methods for Determining Average Grain Size. E 112. [3] Takayama Y, Furushiro N, Tozawa T, Kato H, Hori S. Asignificant Method for Estimation of the Grain Size of Polycrystalline Materials. Materials Transaction, JIM, Vol. 32, No. 3 (1991).

28. Thank you very much for your attention!
Questions?

29. Fe-C phase diagram – Modern steels
Alloy of Iron and other elements
The COMPOSITION makes the difference
Flexible properties
Heat treatment
Possible alloys
Different phases
Today
X80 line pipe steel containing 0.06 C, Mn, Nb, Ti, 0.24 Mo, and N in mass % as alloys.

30. Classification of Steels in the petroleum industry
Based on its resistance to H2S and CO2 corrosion, we can differentiate different kind of steels, e.g.:
Carbon Steels
Stainless Steels
Ni-alloys

31. -Pipeline engineering
Properties of different materials
Machining of materials
Microstructure-properties relationship

32. -Pipeline engineering
Properties of different materials
Machining of materials
Microstructure-properties relationship

33. -Pipeline engineering
Properties of different materials
Machining of materials
Microstructure-properties relationship

34. Do we REALLY need materials with higher material strengths?

35. Grain size distribution RESULTS of a sample heated up to 1050 °C

36. Grain size distribution RESULTS of a sample heated up to 1150 °C

37. Grain size distribution RESULTS of a sample heated up to 1250 °C

38. Comparison of LUT and HT-LSCM average grain size measurements [3]

39. HT-LSCM measurements can not be transformed after the Takayama approach, if abnormal grain growth takes place. Once abnormal grain growth beginns the standard deviation changes and it can not be any longer be considered constant. Another approach would be required.