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.
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
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
-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
-Pipeline engineering Properties of different materials Machining of materials Microstructure-properties relationship ΔT Gas composition Longitudinal ground profile Q → n → Dp
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
Do we REALLY need materials with higher material strengths?
Do we REALLY need materials with higher material strengths? YES
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
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
Laser Ultrasonics Technique (LUT) [1] Provided by Professor Militzer M.
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
High Temperature Laser Scanning Confocal Microscopy (HT-LSCM)
Video Grain growth
Average grain size & Grain size distribution MEASUREMENTS of a sample heated up to 1050 °C
Average grain size & Grain size distribution MEASUREMENTS of a sample heated up to 1150 °C
Average grain size & Grain size distribution MEASUREMENTS of a sample heated up to 1250 °C
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]
Grain size distribution RESULTS of a sample heated up to 1050 °C
Grain size distribution RESULTS of a sample heated up to 1150 °C
Grain size distribution RESULTS of a sample heated up to 1250 °C
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
Comparison of LUT and HT-LSCM average grain size measurements
Comparison of LUT and HT-LSCM average grain size measurements
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
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
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 2014. Acta Materialia 60 (2012) 1015-1026. [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).
Thank you very much for your attention! Questions?
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, 1.65 Mn, 0.034 Nb, 0.012 Ti, 0.24 Mo, and 0.005 N in mass % as alloys.
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
-Pipeline engineering Properties of different materials Machining of materials Microstructure-properties relationship
-Pipeline engineering Properties of different materials Machining of materials Microstructure-properties relationship
-Pipeline engineering Properties of different materials Machining of materials Microstructure-properties relationship
Do we REALLY need materials with higher material strengths?
Grain size distribution RESULTS of a sample heated up to 1050 °C
Grain size distribution RESULTS of a sample heated up to 1150 °C
Grain size distribution RESULTS of a sample heated up to 1250 °C
Comparison of LUT and HT-LSCM average grain size measurements [3]
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.