بررسی تغییر خواص استحکامی و سختی فولادH13طی خزش کوتاه مدت

نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانشجوی دکتری، گروه مهندسی مواد، دانشکده فنی و مهندسی، واحد علوم و تحقیقات، دانشگاه آزاد اسلامی

2 استاد، گروه مهندسی مواد، دانشکده فنی و مهندسی، واحد علوم و تحقیقات، دانشگاه آزاد اسلامی،

3 استادیار، گروه مهندسی مواد، دانشکده فنی و مهندسی، واحد علوم و تحقیقات، دانشگاه آزاد اسلامی،

چکیده

تغییر در خواص استحکامی و سختی آلیاژها عامل اصلی در تغییر نرخ کرنش طی خزش است. بنابراین، اندازه گیری این خواص و مطالعه ارتباط آنها با مقاومت خزشی دارای اهمیت می‌باشد. در این پژوهش، ارتباط بین داده‌های سختی و مقاومت به خزش فولاد H13 طی خزش کوتاه مدت مورد مطالعه قرار گرفته است. آزمون‌های خزش تا شکست و نیز کرنش 1% در بازه دمایی C 600 ـ500 و تنش MPa 5/926 ـ872 انجام شد. سختی‌سنجی بر روی کلیه نمونه‌ها و آزمون کشش بر روی نمونه های خزش با کرنش 1% و در دمای محیط صورت پذیرفت. برپایه نتایج، میانگین توان خزشی 4/5 در تمام بازه‌های تنشی و دمایی مبین غالب بودن مکانیزم خزش نابجائی بود. انرژی فعال سازی خزش این فولاد نیز کم‌تر از انرژی فعال‌سازی نفوذ در خود آهن آلفا (برابر 109 کیلوژول بر مول) بود که بیانگر نقش تنش در انرژی فعال سازی ظاهری این آلیاژ بود. همچنین، ارتباط خطی بین نسبت تغییرات سختی به نسبت عمر خزشی این آلیاژ مشاهده شد، هرچند که شیب آن برای دو بخش سر و گیج نمونه‌های خزش مقداری تفاوت از خود نشان ‌داد. چنین ارتباطی، بررسی مقاومت خزشی و تخمین دقیقتر عمر باقیمانده فولاد H13 را امکان‌پذیر می‌سازد.

کلیدواژه‌ها


عنوان مقاله [English]

Study of changes in the strength and hardness of H13 steel during short-term creep

نویسندگان [English]

  • Zohair Sarajan 1
  • Said Nategh 2
  • Hamidreza Najafi 3
1 Ph.D. Candidate, Department of Materials Engineering, Science and Research Branch, Islamic Azad University,
2 Professor, Department of Materials Engineering, Science and Research Branch, Islamic Azad University,
3 Assistant professor, Department of Materials Engineering, Science and Research Branch, Islamic Azad University,
چکیده [English]

Changes in strength and hardness of alloys are the main factor affecting the strain rate during creep. Thus measuring these properties and studying their correlations to creep resistance is an important issue. In the current study, the relationship between hardness and creep resistance for H13 steel was investigated during short-term creep. Creep fracture and 1% creep ductility tests were carried out at 500-600 C and stress of 872-926.5 MPa. Hardness test was carried out on all specimens and tensile test was performed on 1% creep ductility specimens at room temperature. The stress power of 4.5 indicated that dislocation creep was the dominant mechanism. The creep activation energy was lower than the activation energy of the self diffusion of alpha iron (109 kJ/mol), which indicated the role of stress in the apparent activation energy of this alloy. A linear relationship has been observed between hardness variation ratio and creep life ratio, although the slopes for the head and gage were slightly different. This linear relationship makes it possible to more accurately predict the life of H13 steel in creep condition.

کلیدواژه‌ها [English]

  • Creep
  • H13 steel
  • Yield strength
  • Hardness
  • Modulus of Elasticity

[1] A.Eser, C.Broeckmann and C.Simsir, Multiscale modeling of tempering of AISI H13 hot-work tool steel1: Prediction of microstructure evolution and coupling with mechanical properties. Computational Materials Science 113 (2016) 292-300

[2] W. Zleppnig et al, Influence of the structure and of the Temperature Field on the Formation and Propagation of  Thermal Fatigue Cracks. Fracture Control of Engineering Structures-ECF 6 (1986) 139-147.

[3] J. C. Benedyk, Aerospace and high performance alloys database. Ferrous (2008) 1-135.

[4] T. Ueda and T. Matsuo, Studies on the Torsional Creep Strength of 5% Cr Hot Work Die Steel and Mo-High Speed Steel. Journal of the Society of Materials Science 14(146) (1965) 879-885.

[5] W. R. Prudente et al,  Microstructural evolution under tempering heat treatment in AISI H13 hot-work tool steel. International journal of engineering research and applications 7 (4) (2017) 67-71.

[6] Y. Guanghua et al, Effect of heat treatment on mechanical properties of H13 steel. Metal Science and Heat Treatment 52 (7-8) (2010) 393-395.

[7] J. Hald and L. Korcakova, Precipitate stability in creep resistant ferritic steels‐Experimental investigations and modeling. The Iron and Steel Institute of Japan International 43 (2003) 420‐427.

[8] Y. Kadoya, B. E. Dyson, and M. McLean, Microstructural stability during creep of Moor W‐bearing 12Cr steels. Metallurgical and Materials Transactions A 33 (2002) 2549‐2557.

[9] Y. Qin, G. Gotz, and W. Blum, Subgrain structure during annealing and creep of the cast martensitic Cr‐steel G‐X12CrMoWVNbN 10‐1‐1. Metallurgical and Materials Transactions A 341 (2003) 211‐215.

[10] H. Wurmbauer et al, Short-term creep behavior of a Cr Mo V hot-work tool steel. International Journal of Materials Research 100 (2009) 1066-1073.

[11] G. E. Dieter. Mechanical Metallurgy. 3rd ed., Mc Graw-Hill Book Co., New York 1986.

[12] V. B. John. Testing of Materials, 1992, Macmillan Education LTD, London 1992.

[13] F. Abe, Creep rates and strengthening mechanisms in tungsten‐strengthened 9Cr steels. Materials Science and Engineering A 319‐321 (2001) 770‐773.

[14] P. J. Ennis et al, Microstructural stability and creep rupture strength of the martensitic steel P92 for advanced power plant. Acta Materialia 45 (1997) 4901‐4907.

[15] K. Maruyama, K. Sawada, and J.Koike, Strengthening mechanisms of creep resistant tempered martensitic steel. ISIJ International 41 (2001) 641‐653.

[16] S.Z. Qamar, Effect of heat treatment on mechanical properties of H11 tool steel. Journal of Achievements in Materials and Manufacturing Engineering 35 (2) (2009) 115-120.

[17] J. Gu, J. Li and Y. Chen, Microstructure and Strengthening-Toughening Mechanism of Nitrogen-Alloyed 4Cr5Mo2V Hot-Working Die Steel. Metals 7 (2017) 1-14.

[18] H. Ghassemi-Armaki et al, Static recovery of tempered lath martensite microstructures during long-term aging in 9-12% Cr heat resistant steels. Materials Letters 63 (2009) 2423-2425.

[19] M. Mikami, Effects of Dislocation Substructure on Creep Deformation Behavior in 0.2%C-9%Cr Steel. The Iron and Steel Institute of Japan International 56 (10) (2016) 1840-1846.

[20]A. Mehmanparast et al, Creep crack growth rate predictions in 316H steel using stress dependent creep ductility. Materials at High Temperatures 31 (1) (2014) 84-94.

[21] T. Sourmail, Precipitation in creep resistant austenitic stainless steels. Materials Science and Technology 17 (2001) 1-14.

[22] M. Taneike, F. Abe, and K. Sawada, Creep strengthening of steel at high temperatures using Nano-sized carbonitride dispersions. Nature 424 (2003) 294-296.

[23] R. C. Thomson and H. K. D. H. Bhadeshia, Carbide precipitation in 12Cr1MoV power plant steel. Metallurgical Transactions A-Physical Metallurgy and Materials Science 23 (1992) 1171-1179.

[24] M. Kassner. Fundamentals of Creep in Metals and Alloys. 3rd ed., Elsevier, London 2015.

[25] A. Dronhofer et al, On the nature of internal interfaces in tempered martensite ferritic steels. Zeitschrift fur Metallkunde 94 (2003) 511-520.

[26] C. Scheu et al, Requirements for microstructural investigations of steels used in modern power plants. Zeitschrift fur Metallkunde 96 (2005) 653-659.

[27] H.Wurmbauer et al, Short-term creep behavior of chromium rich hot-work tool steels. Materialwissenschaft und Werkstofftechnik 41 (1) (2010) 18-28.

[28] H. Berns, C. Broeckmann and H. F. Hinz, Creep of High Speed Steels Part1- Experimental Investigations. 6th International Tooling Conference, Karlstad, Sweden (2002) 453-476. 

[29] A. A. Vasilyev et al, Effect of Alloying on the Self-Diffusion Activation Energy in γ-Iron. Physics of the Solid State 53 (11) (2011) 2194-2200.

[30] T. A. Tchizhik, and A. A. Tchizhik, Optimization of the heat treatment for steam and gas turbine parts manufactured from 9-12% Cr steels. Journal of Materials Processing Technology 77 (1998) 226-232.

[31] H. M. Tawancy and L. Al-Hdhrami, Failure of refurbished turbine blades in a power station by improper heat treatment. Engineering Failure Analysis 16 (3) (2009) 810-815.

[32] F. R. N. Nabarro and H. L. De Villiers. The physics of creep:creep and creep‐resistant alloys, Taylor & Francis, London 1995.

[33] D. A. Padmavathi, Potential Energy Curves & Material Properties. Materials Sciences and Applications (2011) 97-104.

[34]F. Abe, T. U. Kern, and R. Viswanathan, Creep-resistant steels. Woodhead Publishing, CRC Press, New York 2008.

[35] A. I. Medved and A. E. Bryukhanov, The Variation of Young’s Modulus and the Hardness with Tempering of some Quenched Chromium Steels. Meta.llovedenie i Termicheskaya Obrabotka Metallov 9 (1969) 35-38.

[36] K. Sawada et al, Elastic properties of heat resistant steels after long-term creep exposure. Materials at High Temperatures 25 (3) (2008) 179-185.

[37] G. Eggeler, N. Nilsvang, and B. Ilschner, Microstructural changes in a 12‐percent chromium steel during creep. Steel Research 58 (1987) 97‐103.

[38] G. Eggeler, Microstructural parameters for creep damage quantification. Acta Metallurgica et Materialia 39 (1991) 221‐231.

[39] K. Sawada et al, Contribution of microstructural factors to hardness change during creep exposure in Mod.9Cr‐1Mo steel. The Iron and Steel Institute of Japan International 45 (2005) 1934-1939.

[40] G. Bakic et al, Material characterization of the main steam gate valve made of X20CrMoV 12.1 steel after long term service. Procedia Materials Science 3 (2014) 1512-1517.

[41] K. Sankhala et al, Study of microstructure degradation of boiler tubes due to creep for remaining life analysis. Int. Journal of Engineering Research and Applications 4(7) (2014) 93-99.

[42] C. Panait et al, Study of the microstructure of the Grade 91 steel after more than 100,000h of creep exposure at 600°C. International Journal of Pressure Vessels and Piping 87 (2010) 1-14.