Microstructure and Mechanical Properties in Thermally Treated Cr-Mn-Cu Stainless Steel Welds

  • Taiwo Folorunsho Lawal University of Lagos, Akoka-Yaba, Lagos
  • Muhammed Olawale Hakeem Amuda University of Lagos, Akoka-Yaba, Lagos
  • Fabian Sunday Omonua University of Lagos, Akoka-Yaba, Lagos
  • Kingsley Somtomchukwu Enumah University of Lagos, Akoka-Yaba, Lagos
Keywords: Austenitic stainless steel grades, mechanical properties, microstructural evolution, pre and post weld thermal treatment, tungsten inert gas arc welding, welds grain morphology

Abstract

In the present investigation, the mechanical properties in Cr-Mn-Cu austenitic stainless steel subjected to pre-weld and post-weld thermal treatments were characterized relative to microstructural features in the welds. Characterisation of microstructure evolution in the thermally treated welds indicated the development of refined cellular/dendritic structure relative to elongated columnar dendritic microstructure in the as-welded austenitic stainless steel. Specifically, pre-welds exhibited coarse grain morphology in contrast to refined morphology in post thermally treated welds. The contrast in grain morphology in the pre-weld and post-weld thermally treated welds was attributed to the differential cooling rates in these different thermal treatment conditions. Hardness value in the thermally treated welds decreases with increasing heat input across the various zones of the weld suggesting the development of equilibrium structure in welds subjected to either pre or post-weld thermal treatment. The highest value was however obtained in post-thermally treated welds. Tensile strength was highest in pre-weld thermally treated coupons at 953 MPa  followed by as-welded coupons at 947 MPa  and the least in post-weld thermally treated coupons at 921 MPa. A major finding from the investigation was that tensile strength decreases with increasing heat input across the process parameters considered irrespective of the thermal treatment conditions. This trend was in concord with the trend established in literature

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Author Biographies

Taiwo Folorunsho Lawal, University of Lagos, Akoka-Yaba, Lagos
Materials Development and Processing Research Group, Department of Metallurgical and Materials Engineering.
Muhammed Olawale Hakeem Amuda, University of Lagos, Akoka-Yaba, Lagos
Materials Development and Processing Research Group, Department of Metallurgical and Materials Engineering.
Fabian Sunday Omonua, University of Lagos, Akoka-Yaba, Lagos
Materials Development and Processing Research Group, Department of Metallurgical and Materials Engineering.
Kingsley Somtomchukwu Enumah, University of Lagos, Akoka-Yaba, Lagos
Materials Development and Processing Research Group, Department of Metallurgical and Materials Engineering.
Published
26-04-2020
How to Cite
Lawal, T. F., Amuda, M. O. H., Omonua, F. S., & Enumah, K. S. (2020). Microstructure and Mechanical Properties in Thermally Treated Cr-Mn-Cu Stainless Steel Welds. International Journal of Integrated Engineering, 12(4), 161-171. Retrieved from https://publisher.uthm.edu.my/ojs/index.php/ijie/article/view/4351
Section
Articles