Effect of repair welds on the microstructure and mechanical properties of 9Cr1Mo welding joint

Authors

Faculty of Mechanical and Energy Engineering, Shahid Beheshti University, Tehran, Iran

Abstract

9Cr1Mo steel is widely used in the construction of power plant components. Since performing periodic repairs is one of the most important requirements for industrial use of 9Cr1Mo steel, in the present study, the repair welding of the steel and post-weld heat treatments was carried out and its effect on the mechanical properties and microstructural evolutions after several stages of repair welding was studied. Therefore, a detailed structure-property relationship of weld metal, base metal, and HAZ using optical microscopy, scanning electron microscopy techniques as well as room temperature tensile test, impact test, and microhardness examinations were found. The results showed that there was a direct relationship between the number of welding repairs and the increase in average hardness. Moreover, the hardness gradient in the several welded samples was significantly higher than the one-pass welded sample. On the other hand, post-weld heat treatment operations increased the number of precipitations in the weld metal and HAZ and the size of primary austenite grains in the weld metal and HAZ was more homogeneous.

Keywords

References

[1] Pandey C, Saini N, Mahapatra MM, Kumar P (2016) Hydrogen induced cold cracking of creep resistant ferritic P91 steel for different diffusible Hydrogen levels in deposited metal. Int J Hydrogen Energy 41(39):17695-17712.
[2] Das CR, Albert SK, Swaminathan J, Bhaduri AK, Murty BS (2013) Effect of boron on creep behaviour of inter-critically annealed modified 9Cr-1Mo steel. Proc. Eng. 6th Int. Conf. Creep, Fatigue and Creep Fatigue Interaction 55: 402-407.
[3] Das CR, Albert SK, Swaminathan J, Bhaduri AK, Murty BS (2012) Improvement in creep resistance in modified 9Cr1Mo steel weldment by boron addition. Weld World 56(7-8):10-17.
[4] Thomas Paul V, Saroja S, Vijayalakshmi M (2008) Microstructural stability of modified 9Cr-1Mo steel during long term exposures at elevated temperatures. J Nucl Mater 378(1):273-281.
[5] Serna JA, Afanador W (2001) Estimation of improved productivity based on Materials substitution in high temperature applications. ASTM A-335, 2(2):125-135.
[6] Wheeldon J, Parkes J, Dillon D (2008) A proposed initiative by EPRI to advance deployment of ultra-supercritical pulverized coal power plant technology with near-zero emissions and CO2 capture and storage. 5th Int. Conf. Adv. Mater. Tech. Fossil Power Plants, Marco Island, FL, USA, EPRI, 82-91.
[7] Pandey C, Mahapatra MM, Kumar P, Saini N Srivastava A (2017) Microstructure and mechanical property relationship for different heat treatment and hydrogen level in multi-pass welded P91 steel joint. J Manuf Processes 28(1): 220-234.
[8] چرخی م، اکبری د (۱۳۹۶) بررسی اثر پیشگرم بر روی کاهش تنش‌های پسماند در جوشکاری تعمیری لوله های فولادی. مهندسی مکانیک مدرس 10-1 :(12)17.
[9] Coleman KK, Newell WF Jr (2007) P91 and beyond welding the new-generation Cr-Mo alloys for high-temperature service. Weld J Aug: 29-33.
[10] Albert SK, Ramasubbu V, Sundar Raj SI,    Bhaduri AA (2011) Hydrogen-assisted cracking susceptibility of modified 9Cr-1Mo steel and its weld metal. Weld World 55(7-8): 66-74.
[11] Magudeeswaran G, Balasubramanian V, Madhusudhan Reddy G (2008) Hydrogen induced cold cracking studies on armour grade high strength, quenched and tempered steel weldments. Int J Hydrogen Energy 33(7): 1897-1908.
[12] Yue X (2015) Investigation on heat-affected zone hydrogeninduced cracking of high-strength naval steels using the Granjon implant test. Weld World 59(1): 77-89.
[13] Arivazhagan B, Vasudevan M (2014) A comparative study on the effect of GTAW processes on the microstructure and mechanical properties of P91 steel weld joints. J Manuf Processes 16(2): 305-311.
[14] Vora J, Badheka V (2017) Experimental investigation on microstructure and mechanical properties of activated TIG welded reduced activation ferritic/martensiticsteel joints. J Manuf Processes 25: 85-93.
[15] Goyal S, Laha K, Chandravathi KS, Parameswaran P, Mathew MD (2011) Finite element analysis of type IV cracking in 2. 25Cr–1Mo steel weldment based on micro-mechanistic approach. Philos Mag 91(23): 3128-3154.
[16] Parker J (2013) Factors affecting Type IV creep damage in Grade 91 steel welds. Mater Sci Eng A 578: 430-437.
[17] Wang Y, Kannan R, Li L (2016) Characterization of as-welded microstructure of heataffected zone in modified 9Cr–1Mo–V–Nb steel weldment. Mater Charact 118: 225–234.
[18] مرادی م، خرم ع، عبدالهی هـ (1396) بررسی خواص متالورژیکی و مکانیکی در قطعات جوشکاری شده به روش تیگ جهت جایگزینی مواد. مجله مکانیک سازه‌ها و شاره‌ها 95-87 :(4)7.
Journal of Solid and Fluid Mechanics
Volume 10, Issue 2
June 2020
Pages 29-44

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