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Title: Microstructural Development and Mechanical Properties of Friction Stir Welded Ferritic Stainless Steel AISI 409

Journal Article · · Journal of Materials Engineering and Performance
 [1];  [1];  [2];  [3]
  1. The British University in Egypt, Mechanical Engineering Department (Egypt)
  2. University of Birmingham, School of Metallurgy and Materials (United Kingdom)
  3. Suez University, Suez and Sinai Metallurgical and Materials Research Center of Scientific Excellence (SSMMR-CSE) (Egypt)

This work investigates the effect of friction stir welding process parameters (rotation rate and traverse speed) on the microstructural evolution of friction stir welded (FSWed) ferritic stainless steel (FSS) AISI 409. Optical microscope, scanning electron microscope and electron backscattering diffraction are used to quantitatively assess the development in grain structure and texture. The microstructural development suggested that thermo-mechanical deformation occurs in the stir zone within the austenite/ferrite phase region, ultimately transforming upon cooling into bainitic/ferritic microstructure. The fraction and size of the bainitic/ferritic grains are found to vary through the thickness of the joints. High fractions of coarse ferritic grains are found near the top of the stir zone, and low fraction of fine ferritic grains is found near the bottom of the stir zone. This bainitic/ferritic grain structure resulted in an increase in the hardness of the stir zone by about 74% relative to the base material. The tensile strength of the FSWed FSS joints is almost at the same level of the base material with reduction in the ductility as a result of the increased hardness of the weld zone.

OSTI ID:
22970409
Journal Information:
Journal of Materials Engineering and Performance, Vol. 28, Issue 10; Other Information: Copyright (c) 2019 ASM International; Country of input: International Atomic Energy Agency (IAEA); ISSN 1059-9495
Country of Publication:
United States
Language:
English