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Chemistry Changes for HTP Proposed Work Group

Presentation at API E&P Summer Standards Meeting San Francisco, CA

June 2015

New Work Item Proposal Proposal considers 5L changes to better reflect

micro-alloy theory in defining chemical limits. The proposal was raised in conjunction with HIPERC

work from Europe and considering the history of successful application of lower C, micro-alloyed steels processed with modern rolling methods including high temperature processing (HTP) worldwide.

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Context Higher strength steels for X70 and X80 transmission pipelines

have progressively been using much lower carbon options which allow the effective use of microalloying elements such as vanadium, niobium and titanium.

Combined with thermo-mechanical rolling and accelerated cooling or high temperature processing (HTP) these steels are providing excellent strength, toughness and weldability.

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Related advantages Theoretically based microalloy addition limitations related to

maximum carbon content. Consistent chemical composition restrictions between body

and other key annexes of API 5L including H (Sour) and J (offshore).

Annex H (Sour) - Reductions in carbon and the ability to increase niobium at the expense of manganese will reduce segregation and enhance properties.

Annex J (offshore) - Improved toughness, reduced segregation and improved weldability.

The focus is on welded pipe grades X52ME/L360ME and higher

These requirements were the basis of metallurgical developments especially in steel coils for spiral pipes and are the reference for International Tenders.

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Present Table 5

The proposal only applies to PSL 2 welded pipe of grade X52M/L360M or higher.

The Nb + V + Ti ≤ 0.15 limitation is retained but controls are put in place to link Nb maxima to lower carbon.

The relationships proposed between maximum carbon levels and maximum niobium levels take account of a number of inputs (see references) including the recommendations of the 2010 HIPERC report previously circulated to members.

Additional proposal made to consider Ti

limitations to prevent embrittlement by large cuboids of TiN and to ensure optimum grain coarsening response during welding.

Proposed evolution of Table 5

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Revise note g as follows: g Limitations on Nb, V and Ti as follows: * Additional Ti limitations may be considered to address Ti embrittlement

C max Nb max Ti max* Nb+V+Ti

0.12 0.08 0.025 <=0.15

0.10 0.09 0.025 <=0.15

0.08 0.10 0.025 <=0.15

0.06 0.13 0.025 <=0.15

0.04 0.15 0.025 <=0.15

Annex H (Sour Service) and Annex J (Offshore Service) Significant experience with higher Nb sour and offshore pipelines (see

attached technical references) Proposal: Harmonize following Table 5 proposed changes (details to

be developed)

Proposal for changes to Annexes H & J

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HTP process What is HPT steel? Metallurgical principles of HTP steel Nb – C Solubility Diagram

Projects utilizing HTP design On-shore projects - various Sour Service - Cantrell project example Offshore service - Cameron Highway project example

Composition Limits of various specifications Carbon Niobium

Line Pipe Weldability Development Bibliography

Technical Data and References

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Thanks

Presentation at API E&P Summer Standards Meeting

San Francisco, CA June 2015

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What is HTP* Steel? (* High Temperature Processed)

Conventional Steel 0.04%Nb FRT 710-830°C HTP Steel 0.10%Nb FRT 840-910°C

Typical HTP steel

C 0.05%; Si 0.12%; Mn 1.55%; Cu 0.24%; Cr 0.23%; Ni 0.13%; Nb = 0.095% Pcm ~0.16%

Metallurgical Principles of HTP Steel Large amount of niobium, up to 0.15 percent, can be

dissolved in austenite during reheating when carbon is below 0.04 percent, i.e., approaching stoichiometry.

Solute niobium increases the temperature of austenite recrystallization due to solute drag and eventually strain induced precipitation of niobium carbonitrides.

Residual solute niobium lowers the austenite to ferrite transformation temperature and enhances grain refinement.

Niobium-Carbon Solubility Diagram

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Project Year Company Country Product Grade WT (mm) Tonnes

TCPL/NOVACORP 1972- present Ipsco/Evraz Canada Coil and Pipe X70/X80 11.8 1,500,000 (HTP

Mod.)**

TCPL, Hearst, ON 1982 Algoma Steel Canadian Phoenix Canada Plate Pipe X70 15.7 35,000

Iroquois Project 1990 Stelco Canada Pipe X65 20.0 18,000

Cantarell 1998 Mittal Steel Mexico, USA, Romania

Slab, Plate, and Pipe X70 sour gas 22.6 65,000

Cameron Highway, offshore 2003 Azovstal Steel Welspun

Ukraine India Plate Pipe

X65 18.0 137,000

Cheyenne Plains 2004 Oregon Steel IPSCO USA Plate, Coil,

and Pipe X80 11.8/14.6 28,000

1st West-East Gas Pipeline 2004 BaoSteel Julong Pipe

China China China

Plate and Coil Plate

Pipe

X70 X70 X70

16.4 650,000

Independence Trail, offshore 2005 Azovstal

Welspun Ukraine

India Plate Pipe X70 30.9 112,000

TCPL 2005 Azovstal Welspun

Ukraine India

Plate Pipe X75 (X80) 22.0 800

Rockies Express 2007- 2009 Oregon Steel USA Plate, Coil,

Pipe X70/X80 12.3/14.3/15.9 ~1,000,000

Golden Pass 2007 Welspun India Plate X70 25,500

2nd West-East Gas Pipeline 2008- 2010 BaoSteel NISCO

Julong Pipe China Plate, Coil,

Pipe X80 18.4 ~4,500,000

3rd West-East Pipeline 2012-2015 Baosteel

Bohai Baoji

China Plate, Coil, Pipe X80 18.4 ~2,000,000

Projects utilizing the HTP alloy design

** no-Mo Acicular Ferrite

Sour Service Project Example

Spec C Mn S Nb Cu Cr Ni Ti N Ca

max .055 1.6 .003 .11 .35 .30 .20 .015 .006 .002

Canatrell project installed in 1998 of 22.6mm WT X70 sour gas (65,000 tons)

This composition would not meet the Nb sour service restrictions of Annex H.

Reductions in carbon and the ability to increase niobium at the expense of manganese will reduce segregation and enhance sour properties.

Offshore Service Project Example

Cameron Highway project installed in 2003 of 18.0mm WT X65 offshore service (137,000 tons)

This composition would not meet the Nb offshore service restrictions of Annex J.

Improved toughness, reduced segregation and improved weldability will all result.

Spec C Mn S Nb Cu Cr Mo Ni Ti N Ca

max .10 1.7 .008 .10 .40 .30 0.50 .85 .015 .006 .002

Carbon Limits of Various Specifications

Niobium Limits of Various Specifications

Line Pipe Weldability Development

IPC2014-33502: Development of X80M Line Pipe Steel for Spiral Welded Pipes with low temp toughness and excellent weldability Nuria Sanchez ArcelorMittal Global R&D / OCAS NV, Özlem E. Güngör ArcelorMittal Global R&D / OCAS NV, Martin Liebeherr ArcelorMittal Global R&D / OCAS NV, Nenad Ilić ArcelorMittal Bremen

European standard: gas pipelines general metallurgical principles 2014 Eric Hivert EH Consultant France

IPC2014-33492: Girth weldability evaluation SAWH 23,70mm X70 high Nb containing line pipe steels Özlem E. Güngör ArcelorMittal Global R&D / OCAS NV, Martin Liebeherr ArcelorMittal Global R&D / OCAS NV, Hervé Luccioni ArcelorMittal Commercial FCE

Weldability X70 & X80 2014: steels Özlem E. Güngör ArcelorMittal Global R&D / OCAS NV, Martin Liebeherr ArcelorMittal Global R&D / OCAS NV

HIPERC: A novel, high performance, economic steel concept for linepipe and general structural use L. J Drewett, S. Bremer, M. Liebeherr, W. De Waele, A. Martín-Meizoso, J. Brózda, B. Zeislmair, H. Morbacher, D. Porter, Dr N. Gubeljak

Bibliography

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J. M. Gray, A Guide for Understanding & Specifying Chemical Composition of High Strength Linepipe Steels, Microalloyed Steel Institute LP Technical Note April 2009

M. Lin & R. L. Bodnar, Effects of Composition and Processing Conditions in a 0.03% C- 0.09% Nb X70 Linepipe steel, Proceedings of 40th NWSP Conference ISS, 1998, p573

W. J. Fazackerly at al, First X 80 HSLA Pipeline in the USA (reference to be provided)

J. M. Gray & W. G. Wilson, Molycorp Develops X80 Arctic Pipeline Steel, Pipeline and Gas Journal, December 1972

Experience with Low Carbon HSLA Steel Containing 0.06 to 0.10 percent niobium CBMM Technical Report

J.M. Gray, Metallurgical Concepts and Status of Development of High Temperature Processed (HTP) Steel Development, Microalloyed Pipe Steels for the Oil and Gas Industry, Seminar Moscow, Russia, April 2-4, 2013

F. Siciliano, D. G. Stalheim & J. M. Gray, Modern High Strength Steels for Oil and Gas Transmission Pipelines, Proceedings of IPC 7th International Pipeline Conference September 29- 3 October Calgary, Alberta, Canada, 2008

Bibliography

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Metallurgical concepts and full scale testing of a high toughness H2S Resistant 0.03% C, 0.10 % Nb Steel. CBMM Technical Report

J. M. Gray, Ultra Low-Manganese High strength Toughness HTP Sour Service Linepipe Steel, Origin as per reference 6.

J. M. Gray, Low Manganese Sour Service Linepipe Steel, Proceedings of Microalloyed Steels for Sour Service International Seminar, Sao Paulo, August 2012, p 165-182

P.R Kirkwood, The Weldability of Modern Niobium microalloyed structural steels, Value- Added Niobium Microalloyed Constructional Steels Symposium 5-7, November, Singapore, 2012

P. R. Kirkwood. Offshore Structural Steels Weldability Standards Evolution to Support Innovation. Proceedings of International Symposium on Steels for Offshore Platforms, Hainan Island, China, December 4-6, 2013, p39

Bremer et al, A Novel Alloying Concept For Thermo-Mechanical Hot Rolled Strip for Large Diameter HTS (Helical Two Step) Line Pipe. Proceedings of IPC 2008, 7TH International Pipeline Conference, September 29-October 3, 2008 Calgary, Alberta, Canada. This paper was also awarded the CBMM sponsored 2010 Charles Hatchett Medal.

Bibliography

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