Available online at www.sciencedirect.com ScienceDirect Materials Today: Proceedings 4 (2017) 234–243 www.materialstoday.com/proceedings E-mail address: mamuda@unilag.edu.ng 2214-7853© 2017 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the conference committee members of the 5th International conference on Materials Processing and Characterization. 5th International Conference of Materials Processing and Characterization (ICMPC 2016) Influences of Energy Input and Metal Powder Addition on Carbide Precipitation in AISI 430 Ferritic Stainless Steel Welds M.O.H. Amuda a, *, E. T. Akinlabi and S. Mridha c 1 Modern and Advanced Manufacturing Systems Research Group, Department of Mechanical Engineering Science, University of Johannesburg, 2006, South Africa 2 Materials Development and Processing Research Group, Department of Metallurgical and Materials Engineering, University of Lagos, Lagos, Nigeria 101017 3 Department of Mechanical and Aerospace Engineering, University of Strathclyde, G11XJ, Glasgow UK Abstract In the present work, 16% chromium AISI 430 ferritic stainless steel weld produced under different conditions of energy input and metal powder addition using TIG torch melting is investigated for carbide precipitation. A Box Behnken experimental design paradigm is invoked with current, speed and metal powder concentration as the primary variables while type of powder is the categorical variable. The result indicates that for a given concentration of metal powder in the melt pool, the sensitized geometry increases with energy input. Titanium as well as the mixture of aluminum and titanium powders reduces the width of the sensitized zone while aluminum powder increases the width of the zone. Titanium powder prevents the development of completely ditched structure in the high temperature heat affected zone (HTHAZ) whereas aluminum powder accelerates the formation of ditched structure in the HAZ. 2214-7853© 2017 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the conference committee members of the 5th International conference on Materials Processing and Characterization Keywords: carbide precipitation, metal powder addition, energy input, HTHAZ, AISI 430 ferritic stainless steel welds. 1. Introduction: Ferritic stainless steel (FSS) represents an attractive alternative to the costlier austenitic variety due to the near absence of nickel in its composition [1]. It is also credited with better stress corrosion cracking resistance in caustic and chloride environments than its closest competitors. It performs excellently in the shielding of radiation in nuclear facilities and generally appealing in other less stringent conditions such as automotive exhaust systems and aesthetic finishes in architectural systems [2]. Despite these attributes, this grade of steel is rarely used in engineering systems because its fabrication via conventional fusion welding techniques is associated with several challenges such as grain coarsening leading to loss of mechanical properties particularly lower ductility. Other challenges include a wide brittle to ductiletransition temperature, and loss of high temperature oxidation resistance [3]. Therefore, in the last few decades, research efforts have focused on improving the strength attributes of the weld section of the FSS [4]. Much of these efforts are concerned with achieving refined grain structure in the weld. In furtherance of this target, Amuda et