The microstructure and mechanical properties of FSPed HSLA steel

• Autorzy: Aktarer S. M. , Küçükömeroğlu T.
• Języki publikacji: EN

Abstrakty

EN

Purpose: High-strength low-alloy (HSLA) steels have been used in a wide range of applications from automotive to ship building industry due to their low weight, formability and good weld ability. However, especially in the automotive industry, it is still attempted to improve this steel for the better formability and strength properties. Grain refinement is a well-known method to improve mechanical properties of metallic materials without changing their chemical compositions. Friction stir processing (FSP) is a new method of enhancing the properties of metals as a result of grain refinement by severe plastic deformation, which is based on the basic principles of Friction Stir Welding (FSW) technique. The purpose of this study is to investigate microstructural alteration and the main mechanical properties of HSLA after friction stir processing. Design/methodology/approach: HSLA steel sheet with a thickness of 1.5 mm was processed using a tungsten carbide (WC) tool consisting of a cylindrical shoulder and a cylindrical conical pin. The parameters of FSP are kept to a fixed tool rotation speed of 1600 rpm, traverse speed of 170 mm.min-1 and down force of 5 kN. The evaluation after and before FSPed of HSLA steel was performed by optical microscope, scanning electron microscope, tensile test and hardness measurement. Findings: After FSP, refined microstructure brought about a considerable increase in both hardness and strength values. The increase in the yield and tensile strength after FSP was about30% and 34%, respectively. Research limitations/implications: Electron backscatter diffraction (EBSD) mapping could not be done in this study. The EBSD mapping should be performed for detailed microstructural characterization of processed zone such as grain size distribution and misorientation angle distribution. Practical implications: FSP can be applied to other steel to obtain high strength steel without any decrease in their ductility properties by means of grain boundary strengthening mechanism. Originality/value: FSP, as a severe plastically deformation technique, is applied to many aluminium alloys and steels. However, only few studies were reported on FSPed HSLA steels. Moreover, further investigations are needed to identify the microstructural and mechanical properties of the FSPed HSLA steels.

Słowa kluczowe

EN

friction stir processing; high-strength low-alloy steel; microstructure; mechanical properties

PL

modyfikacja tarciowa z przemieszaniem materiału; stal niskostopowa o wysokiej wytrzymałości; mikrostruktura; właściwości mechaniczne

• Wydawca: International OCSCO World Press
• Czasopismo: Journal of Achievements in Materials and Manufacturing Engineering
• Rocznik: 2016
• Tom: Vol. 75, nr 2
• Strony: 55--60
• Opis fizyczny: Bibliogr. 16 poz., rys., tab.

Twórcy

autor

Aktarer S. M.

• Department of Automotive Technology , Recep Tayyip Erdogan University, Rize, Turkey

autor

Küçükömeroğlu T.

Bibliografia

• [1] I. Tamura, H. Sekine, T. Tanaka, C. Ouchi, I. Tamura, H. Sekine, et al., Chapter 1 - Introduction, in: Thermomechanical Process. High-Strength Low-Alloy Steels, (1988) 1-16.
• [2] M.C. Zhao, K. Yang, Y. Shan, The effects of thermomechanical control process on microstructures and mechanical properties of a commercial pipeline steel, Materials Science and Engineering: A 335 (2002)14-20.
• [3] R.Z. Valiev, Y. Estrin, Z. Horita, T.G. Langdon, M.J. Zehetbauer, Y. Zhu, Producing Bulk Ultrafine-Grained Materials by Severe Plastic Deformation: Ten Years Later, Jom. (2016) 1-11.
• [4] P. Xue, B.L. Xiao, W.G. Wang, Q. Zhang, D. Wang, Q.Z. Wang, et al., Achieving ultrafine dual-phase structure with superior mechanical property in friction stir processed plain low carbon steel, Materials Science and Engineering: A 575 (2013) 30-34.
• [5] R.S. Mishra, Z.Y. Ma, Friction stir welding and processing, Materials Science and Engineering: R Reports 50 (2005) 1-78.
• [6] Z.Y. Ma, Friction Stir Processing Technology: A Review, Metallurgical and Materials Transactions: A 39 (2008) 642-658.
• [7] S. Ragu Nathan, V. Balasubramanian, S. Malarvizhi, G. Rao, Effect of welding processes on mechanical and microstructural characteristics of high strength low alloy naval grade steel joints, Defence Technology 11 (2015) 308-317.
• [8] T.W. Nelson, S.A. Rose, Controlling hard zone formation in friction stir processed HSLA steel, Journal of Materials Processing Technology 231(2016) 66-74.
• [9] S.J. Barnes, A.R. Bhatti, A. Steuwer, R. Johnson, J. Altenkirch, P.J. Withers, Friction stir welding inHSLA-65 steel: Part I. Influence of weld speed and tool material on microstructural development, Metallurgical and Materials Transactions A 43 (2012)2342-2355.
• [10] A. Steuwer, S.J. Barnes, J. Altenkirch, R. Johnson, P.J. Withers, Friction Stir Welding of HSLA-65 Steel: Part II. The Influence of Weld Speed and Tool Material on the Residual Stress Distribution and Tool Wear, Metallurgical and Materials Transactions A 43(2012) 2356-2365.
• [11] L. Wei, T.W. Nelson, Influence of heat input on post weld microstructure and mechanical properties of friction stir welded HSLA-65 steel, Materials Science and Engineering A 556 (2012) 51-59.
• [12] J. Young, D. Field, T. Nelson, Material flow during friction stir welding of HSLA 65 steel, Metallurgical and Materials Transactions A 44(2013) 3167-3175.
• [13] R.S. Mishra, Z.Y. Ma, Friction stir welding and processing, Materials Science and Engineering Reports 50 (2005) 1-78.
• [14] G.M. Xie, H.B. Cui, Z.A. Luo, W. Yu, J. Ma, G.D. Wang, Effect of Rotation Rate on Microstructure and Mechanical Properties of Friction Stir Spot WeldedDP780 Steel, Journal of Materials Science and Technology 32 (2015) 326-332.
• [15] P.L. Threadgill, Terminology in friction stir welding, Science and Technology of Welding and Joining 12(2007) 357-360.
• [16] M. Hajian, A. Abdollah-zadeh, S.S. Rezaei-Nejad, H. Assadi, S.M.M. Hadavi, K. Chung, M. Shokouhimehr, Microstructure and mechanical properties of friction stir processed AISI 316Lstainlesssteel, Materials and Design 67 (2015) 82-94.