Contents lists available at ScienceDirect Journal of Manufacturing Processes journal homepage: www.elsevier.com/locate/manpro Weld joint design and thermal aging influence on the metallurgical, sensitization and pitting corrosion behavior of AISI 304L stainless steel welds Jastej Singh, A.S. Shahi ⁎ Department of Mechanical Engineering, Sant Longowal Institute of Engineering & Technology, (Deemed to be University), Longowal, Sangrur, 148106, Punjab, India ARTICLE INFO Keywords: Austenitic stainless steel Joint design Microstructure Microhardness Sensitization Pitting corrosion ABSTRACT Experimental investigations were carried out to study the influence of weld joint design and post weld thermal aging treatments on the metallurgical, intergranular and pitting corrosion behavior of AISI 304L stainless steel welded joints. 10 mm thick linear weld joints were fabricated using gas metal arc welding process using single-V and double-V joint design with an average heat input of 503.42 J/mm and 562.78 J/mm respectively. Thermal aging of these welds was carried out at 750 °C for 0.5 h and 4 h, and the cooling media used was furnace, air and water quench (used separately for each specimen), so as to induce variable degree of carbide precipitation in different zones of these welds. Microstructural studies revealed that the extent of carbide precipitation was more in case of welds made using double-V joint design as compared to single-V joint welds. Degree of sensitization (DOS) and pitting performance of these welds evaluated using double loop electrochemical potentiokinetic re- activation (DLEPR) technique and potentiodynamic anodic polarization technique respectively, further showed that single-V joint performed better in terms of corrosion properties owing to lesser precipitation as compared to the double-V joint. This study shows that in comparison to double-V joint, single-V joint design can prove to be an important part of fabrication procedures where service conditions demand better corrosion properties of these welds. 1. Introduction AISI 304 stainless steel, popularly known as 18/8 steel belongs to family of austenitic stainless steels finds usefulness in plethora of en- gineering applications owing to its moderate cost, superior mechanical performance and corrosion resistance. Typical applications of this steel include its use for storing and transportation of liquefied natural gas (LNG) whose boiling point is -162 °C under 1 atmosphere, bellows used for conduit for liquid fuel and oxidizer in propellant tank of sa- tellite launch vehicle, cryogenic structures [1–3]. AISI 304L is an ex- clusive modification of AISI 304 stainless steel by keeping carbon per- centage below 0.03%. Type 304 and 304L are used to the extent of more than 20,000 tons a year [4]. Despite of its widespread industrial usage, there are various me- tallurgical phenomena which continue to adversely affect its en- gineering performance during various service applications [5]. One of such problems encountered is sensitization which occurs during thermal exposition of this alloy to temperature range of 600–850 °C, where carbon from the matrix combines with chromium to form Cr 23 C 6 at grain boundaries, thus making areas adjacent to grain boundaries scarce in chromium content and these areas then become severely susceptible to attack by corrosive environment thus depreciating cor- rosion resistance [6,7]. Weld joint design is an essential part of any welding procedure specification (WPS) for components required to be welded in a pro- duction route. Prior to carrying out welding, groove formation by beveling of edges is done by machining operation. Grooves thus formed are filled by filler material which may or may not be same as base material during welding. Choice of weld joint design takes into account weld quality and productivity. Effects of weld joint design on performance related aspects like mechanical properties, formation of residual stresses etc. in case of welds have been investigated by various researchers. A study on the effect of different groove designs on quenched and tempered steel welded joints show that joint design variation can exert a strong in- fluence on the mechanical properties of the welds thus indicating that joint design variation plays a strong role on the cooling characteristics of such welds [8]. A comparative evaluation between single-V and double-V weld joints of quenched and tempered steel in terms of bal- listic performance was reported by Balakrishnan et al. [9] wherein https://doi.org/10.1016/j.jmapro.2018.05.004 Received 28 February 2018; Received in revised form 27 April 2018; Accepted 4 May 2018 ⁎ Corresponding author. E-mail addresses: jastejsingh@sliet.ac.in (J. Singh), ashahi@sliet.ac.in (A.S. Shahi). Journal of Manufacturing Processes 33 (2018) 126–135 1526-6125/ © 2018 Published by Elsevier Ltd on behalf of The Society of Manufacturing Engineers. T