کاربرد آلیاژهای آهن – آلومینییم در حضور گازهای گوگردی در دمای بالا

چکیده

آلیاژهای آهن – آلومینیم، یکی از مقاومترین آلیاژهای فلزی در برابر سولفیداسیون حتی درفشارهای پایین اکسیژن می باشند. این آلیاژها به تردی هیدروژنی بسیار حساس بوده که این امر عامل اصلی پایین بودن داکتیلیته آنها در دمای محیط است . استحکام آنها در دماهای بالاتر از C600 دچار افت قابل ملاحظه ای می شود و به علاوه مقاومت خزشی در آنها نسبتاً ضعیف می باشد. با کنترل میکروساختار و اضافات آلیاژی، می توان داکتیلیته آلومینایدهای آهن را تا 15 درصد افزایش داد و به علاوه استحکام در دمای بالا و مقاومت خزشی را در حد بسیاری از فولادهای فریتی و آستنیتی بهبود بخشید . استفاده از این آلیاژها به عنوان پوششهای نفوذی، یک راهکار بسیار مناسب برای دستیابی به مقاومت به سولفیداسیون عالی توأم با خواص مکانیکی مطلوب در دمای بالا می باشد. در این مقاله ابتدا تردی محیطی و خواص مکانیکی دمای محیط و دمای بالای این آلیاژها مورد بررسی قرار می گیرد و سپس علل مقاومت آنها در برابر سولفیداسیون و عوامل موثر بر آن تشریح خواهد شد و سپس به ویژگی کاربرد آنها به عنوان پوششهای نفوذی اشاره می شود.

عنوان مقاله [English]

High Temperature Applications of Iron-Aluminum Alloys Exposed to Sulfur Gases

چکیده [English]

Iron-Aluminum alloys are one of the most resistant alloys against sulfidation/oxidation environments with low oxygen partial pressures. The high sensitivity to hydrogen embrittlement is the main reason for decreasing of their room temperature ductility. There is a drop of strength above 600 C and their creep resistance is fairly weak. It is possible to increase ductility up to 15 percents and improve creep resistance as well as ferritic and austenitic steels through microstructure control and alloy elements. The use of these alloys as diffusion coating is a good alternative to access simultaneously of excellent sulfidation and good mechanical properties in high temperature. In this paper, firstly, the environmental embrittlement and room & high temperature mechanical properties of these alloys are evaluated and then, their sulfidation resistance and the effective factors are explained. Moreover the paper points to usage of them as diffusion coatings.

 
 
 

[1] R.C.John, “ Exploitation of Data of Alloy Corrosion in High-Temperature Gases”,

     Materials Science Forum Vols 369-372(2001) PP 881-922

[2] G. Y. Lai, “Sulfidation Resistance of Various High-Temperature Alloys in Low Oxygen

      Potential Atmospheres”, High Temperature Corrosion in Energy Systems.

[3] V.K.Sikka et al . , “ Iron-Aluminum Alloys Having High Room-Temperature and Method

      for making Same , US Patent 5238645,1993

[4] Edited by N.S. Stoloff & V.K.Sikka,”Physical metallurgy and Processings of Intemetallic

     Compounds, 1996.

[5] I. Baker  & P. Nagpal , “ A Review of the flow and fracture of FeAl “,Procedings of the

     First International Symposium on Structural Intermetallics , TMS, 1993.

[6] Edited by J.R.Davis, “Heat-Resistant Materials”, ASM Specialty Handbook, 1997.

[7] V.K. Sikka, S. Viswanathan and C.G. Mckamey, “Development and Commercialization

     Status of Fe3Al- Based Intermetallic Alloys, Proceedings of the First International

     Symposium on Structural Intermetallics, TMS, 1993.

[8] Krishna Vedula , “ Fe Al and Fe3Al”, Intermetallic Structureal Applications of termetallic

      Compounds , Chapter 9, John wiley & sons, LTD, 2000.

[9] C.G. Mckamey & P.J. Maziaz , “ Heat Treatment Effects for Improved Creep – Rupture

      Resistance of a Fe3Al- Based Alloy”, Intermetallics 6(1998) 303-314

 [10] G. H. Meier and F. S. Pettit, “ Sulfidation and Hot Corrosion of Alloys at Elevated

        Temperatures”, High Temperature Corrosion in Energy Systems,

[11] F.H. Stott et al. “ Preoxidation for the Protection of High-Temperature Alloys in

        Environments of High Sulphur and Low Oxygen Potentials Pertinent to

       Gasification Processes “, High Temperature Corrosion in Energy Systems,

 [12] P. F. Tortorelli and J. H. Devan, “Behavior of Iron aluminides in Oxidizing and

        Oxidizing / Sulfidizing Environments “, Materials Science and Engineering , A153

        (1992) 573-577

[13] P.F. Tortorelli & K. Natesan, “ Critical Factors affecting the High-Temperature

       Corrosion Performance of Iron Aluminides “, Materials Science and Engineering A

       258(1998) 115-125

[14] T. T. Huang et al . , “High Temperature Oxidation of  Fe-18Cr-6 Al Alloy in

        H2/H2O/H2S Gaseous Environments “, High Temperature Corrosion in Energy Systems,

[15] B. A. Pint & P. F. Tortorelli, “ Long- term Oxidation Performance of Ingot-Produced

        Fe3Al Alloys “, Oak Ridge National Laboratory, USA, 1999

[16] S. W. Green and F.H. Stott, “ The Effectiveness of Aluminizing in Protecting Iron-

       Base Alloys in Sulphidizing Gases at High Temperature” , Oxidation of Metas, Vol. 36,

       NOS. ¾ 1991

[17] B. A. Pint & P. F. Tortorelli & Y. Zhang, “ Evaluation of Iron – Aluminide CVD

       Coatings for High Temperature Corrosion Protection”, Metals an Ceramics Division ,

       Oak Ridge National Laboratory , USA, 2001

[18] Benno Ganser et al.,“ Operational Experience with Diffusion Coatings on Steam Cracker

       Tubes”, Presented at the European Federation of Corrosion Workshop Coking and

       Decoking , May 1999, Porto , Portugal .

 

[19] N.J. Simms, J.R. Nicholls and J.E. Oakey, Meterials Performance in Solid Fuel

       Gasification System, Materials Science forum Vols 369-372(2001), PP 947-954

[20] P. F. Tortorelli et al. , “Oxide Defects and Damage Processes in Iron- Based Alumina-

       Formers. “ , Materials Science Forum Vols 369-372(2001) PP 337-344

[21] H. J. Grabke , “ Mechanisms and Prevention of Corrosion in Carbonaceus Gases “ ,

       Materials Science Forum Vols 369-372 (2001) PP 101-108

[22] F.J. Perez et al. , “Cyclic Oxidation Performance of a CVD-FBR Aluminised 18 Cr-8Ni

      Stainless Steel”, Materials Science Forum Vols 369-372(2001) PP 751-758

[23] S. Osgerby et al. ,” Cracking and Spallation of Chromia and Alumina Scales during

       Thermal Cycling “, Materials Science forum Vols 369-372(2001) PP 491-498

[24] B. A. Pint et al. ,”Optimizing the Imperfect Oxidation Performance of Iran Aluminides “,

       Materials Science Forum Vols 369-372(2001) PP 411-418

[25] Caminha et al. ,” Effect of Alumimium Thermal Spray Coating on the Corrosion

       Resistance of a Steel Under Oxidant Atmosphere in a Flaid Catalytic Cracking

       Regenerator “, Materials Science Forum Vols 369-372(2001) PP 655-662

[26] S. W. Banovic & J. N. Dupont, “ Experimental Evaluation of Fe-Al Claddings in High –

       Temperature Sulfidizing Environments”, Supplement to the Welding Journal, march 2001

[27] J. M. Cairney &  P. R. Munroe, “ The effect of chromium on the B2-DO3

        transformation in Fe3 Al”, Journal of Materials Science Letters 18 (1999) 449-452

[28] S. W Banovic & A. R. Marder, “ Corrosion Behavior of Weldable Fe-Al Alloys in

       Oxidizing – Sulfidizing Enviromments” , Energy Research Center, Lehigh  University,

        USA, 2000

[29] Y. Zhang & B.A. Pint, “ Aluminide Coating for Power Generation Applications “,

       Tennesse Technological University, USA, 2002

[30] V. Shankar Rao & V.S. Raga , “ Long-Term Sulfidation Behavior of  Fe3Al - Fe3Al C

       0.69 Iron Aluminides “, Intermetallics 11(2003) 119-128