Modelling of austenite formation in weld heat affected zone of API-X65 and X70 pipeline steels

Subject Areas :

Jaafar Ahmadi rad ¹ , Gholamreza Khalaj ²

1 - Saveh Branch, Islamic Azad University, Saveh, Iran
2 - Islamic Azad University, Saveh Branch

Received: 2017-09-18 Accepted : 2018-12-18 Published : 2018-11-22

Keywords: austenite, transformation, Steel, microalloy, dilatometry,

Abstract :

In the present work the two microalloyed steel (X65 and X70 ) used in oil and gas transition pipeline, was obtained as a hot rolled plate with accelerated cooling. First, weld heat affected zone thermal cycles, according to four-wire tandem submerged arc welding process were analyzed. The Baehr 805A/D dilatometer was used for weld heat affected zone thermal cycles’ simulation. The thermal cycles simulated process for heated region involved heating the steel specimens to the peak temperatures of 950, 1150 and 1350 °C and transformation behaviour and microstructure is investigated. By analyzing the dilatometry results, continuous heating diagram, austenite grain growth and austenite formation kinetics were investigated. Austenite formation modeling was done using Johnson- Mehl- Avrami- Kolmogorov (JMAK) classic equation. The parameter n was found to be relatively independent on temperature (or heating rate); While the parameter k is strongly dependent to temperature, phase fraction transformed and austenite grain growth

References:

 

[1]     T. Gladman, “The Physical Metallurgy of Microalloyed Steels”, The Institute of Materials, London, 2002.

 

[2]       ع. ناظم الرعایا و م. فاضل نجف‌آبادی، "بررسی ریزساختار و خواص مکانیکی اتصال فولاد API-X65 به روش جوشکاری هم زن اصطکاکی"، شماره 4، زمستان 1394.

 

[3]     Y. Weng, H. Dong & Gan Y. (editors), “Advanced Steels the Recent Scenario in Steel Science and Technology”, Springer-Verlag, Berlin, 2011.

 

[4]     W. Sha, “Steels: From Materials Science to Structural Engineering”, Springer-Verlag, London, 2013.

 

[5]       ب. یوسفیان، ک. امینی و م. کثیری، "بررسی تاثیر سرعت سرد کردن، دمای پیشگرم و تغییر ترکیب شیمیایی بر روی ریز ساختار و خواص مکانیکی فولاد میکروآلیاژ وانادیوم دار متوسط کربن"، شماره 2، تابستان 1394.

 

[6]     K. Poorhaydari, B. M. Patchett & D. G. Ivey, “Estimation of Cooling Rate in the Welding of Plates with Intermediate Thickness”, Welding Journal, Vol. 84, pp. 149-155, 2005.

 

[7]     D. P. Dunne, “Review: Interaction of precipitation with recrystallisation and phase transformation in low alloy steels”, Materials Science and Technology, Vol. 26, No. 4, pp. 410-420, 2010.

 

[8]     P. R. Rios, “Relationship between non-isothermal transformation curves and isothermal and non-isothermal kinetics”, Acta Materialia, Vol. 53, No. 18, pp. 4893-4901, 2005.

 

[9]     L. M. Fu, H. R. Wang, W. Wang & A. D. Shan, “Austenite grain growth prediction coupling with drag and pinning effects in low carbon Nb microalloyed steels”, Materials Science and Technology, Vol. 27, No. 6, pp. 996-1001, 2011.

 

[10] M. Shome, D. S. Sarma, O. P. Gupta & O. N. Mohanty, “Precipitate dissolution and grain growth in the heat affected zone of HSLA-100 steel”, ISIJ International, Vol. 43, No. 9, pp. 1431-1437, 2003.

 

[11] Y. Q. Zhang, H. Q. Zhang, W. M. Liu & H. Hou, “Effects of Nb on microstructure and continuous cooling transformation of coarse grain heat-affected zone in 610 MPa class high-strength low-alloy structural steels”, Materials Science and Engineering, Vol. 499A, No. 1-2, pp. 182-186, 2009.

 

[12] C. García De Andrés, F. G. Caballero, C. Capdevila & L. F. Álvarez, “Application of dilatometric analysis to the study of solid-solid phase transformations in steels”, Materials Characterization, Vol. 48, No. 1, pp. 101-111, 2002.

 

[13] A. B. Cota, C. A. M. Lacerda, F. L. G. Oliveira, F. A. Machado & F. G. Da Silva Araújo, “Effect of the austenitizing temperature on the kinetics of ferritic grain growth under continuous cooling of a Nb microalloyed steel”, Scripta Materialia, Vol. 51, No. 7, pp. 721-725, 2004.

 

[14] F. L. G. Oliveira, M. S. Andrade & A. B. Cota, “Kinetics of austenite formation during continuous heating in a low carbon steel”, Materials Characterization, Vol. 58, No. 3, pp. 256-261, 2007.

 

[15] K. Banerjee, M. Militzer, M. Perez & X. Wang, “Nonisothermal austenite grain growth kinetics in a microalloyed x80 linepipe steel”, Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, Vol. 41, No. 12, pp. 3161-3172, 2010.

 

[16] M. Maalekian, R. Radis, M. Militzer, A. Moreau & W. J. Poole, “In situ measurement and modelling of austenite grain growth in a Ti/Nb microalloyed steel”, Acta Materialia, Vol. 60, pp. 1015–1026, 2012.

 

[17] S. Malinov, Z. Guo, W. Sha & A. Wilson, “Differential scanning calorimetry study and computer modeling of β ⇒ α phase transformation in a Ti-6Al-4V alloy”, Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, Vol. 32, No. 4, pp. 879-887, 2001.

 

[18] M. Militzer, R. Pandi & E. B. Hawbolt, “Ferrite nucleation and growth during continuous cooling”, Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, Vol. 27, No. 6, pp. 1547-1556, 1996.

 

[19] H. N. Han & S. H. Park, “Model for cooling and phase transformation behaviour of transformation induced plasticity steel on runout table in hot strip mill”, Materials Science and Technology, Vol. 17, No. 6, pp. 721-726, 2001.

 

[20] D. Liu, F. Fazeli & M. Militzer, “Modeling of microstructure evolution during hot strip rolling of dual phase steels”, ISIJ International, Vol. 47, No. 12, pp. 1789-1798, 2007.

 

[21] M. Militzer, E. B. Hawbolt & T. R. Meadowcroft, “Microstructural model for hot strip rolling of high-strength low-alloy steels”, Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, Vol. 31, No. 4, pp. 1247-1259, 2000.

 

[22] S. Sarkar & M. Militzer, “Microstructure evolution model for hot strip rolling of Nb-Mo microalloyed complex phase steel”, Materials Science and Technology, Vol. 25, No. 9, pp. 1134-1146, 2009.

 

[23] M. Umemoto, N. Komatsubara & I. Tamura, “Prediction of hardenability effects from isothermal transformation kinetics”, Journal of Heat Treating, Vol. 1, No. 3, pp. 57-64, 1980.

 [24] J. Moon, S. Kim, H. Jeong, J. Lee & C. Lee, “Influence of Nb addition on the particle coarsening and microstructure evolution in a Ti-containing steel weld HAZ”, Materials Science and Engineering, Vol. 454-455A, pp. 648-653, 2007.