Electrochemical Potentiokinetic Reactivation Test Research Articles

Influence of ageing treatment time on microstructural evolution, sensitization and self-healing of Inconel 600

Samples of Inconel 600 were thermally aged at 739 °C from 1 up to 300 h followed by water quenching. The changes in microstructure were characterized and its effect on sensitization was evaluated by subjecting the heat-treated samples to double-loop electrochemical potentiokinetic reactivation (DL-EPR) tests. The evolution of the microstructure was analysed in terms of grain size, carbide formation and chromium diffusion by optical and scanning electron microscopy. The results showed that the formation of chromium carbides is rapid at this temperature, increasing the density of carbides at the grain boundaries in the early stages of the ageing treatment. The formation of Cr7C3 and Cr23C6 along the grain boundaries and within the austenitic matrix modified the corrosion behaviour as seen in the measurements of the degree of sensitization (DOS). A decrement in DOS was seen with ageing time up to 200 h, due to the redistribution of chromium, induced by the equilibrium between chromium at grain boundaries and within the matrix. Electron backscattering diffraction suggested that self-healing of the alloy may be due to the mechanism of near-boundary gradient zones, where the increased number of dislocations leads to precipitation of carbides by promoting diffusion and thereby decreasing the Cr-depleted zones.

Experimental investigation of microstructural, mechanical and corrosion properties of 316L and 202 austenitic stainless steel joints using cold metal transfer welding

The objective of the current experimental study is to investigate influence of dissimilar welding between 316 L Austenitic and 202 Austenitic Stainless Steel. This is achieved through the utilization of Cold Metal Transfer (CMT) Welding in conjunction with the GTAW mode. Various welding approaches are employed, including the use of ER316L and ER309L fillers, as well as a no-filler (autogenous) welding technique. Microstructural observation shows martensitic formation in the interface region. The tensile test was conducted by using Universal Testing Machine for the weldment and found that ER316L filler (721 MPa) has higher strength than ER309L (672 MPa) and autogenous weld (528 MPa). Charpy impact test was used to determine toughness of the weldment and found that ER309L Filler weld has toughness (87 J) which is higher than ER316L filler weld (5 4 J) and autogenous weld (23 J). Vicker's hardness test shows that autogenous weld hardness (avg. 193.34 HV) which is highest than ER309L filler (avg.188 HV) and ER316L filler weld (avg. 184.67 HV). The intergranular corrosion test by double loop electrochemical potentiokinetic reactivation (DLEPR) test shows sensitization at highest degree for autogenous weld (18.25 %) than ER316L filler weld (9.22 %) and ER309L filler weld (7.28 %).

An investigation of the effect of sensitization on the metallurgical characteristics of dissimilarly welded austenitic-ferritic stainless steel

Purpose The purpose of this study is to examine the effects of sensitization on the metallurgical characteristics of weld joints made up of austenitic stainless steel (AISI 316L) and ferritic stainless steel (AISI 430), using the gas tungsten arc welding (GTAW) process with ER316L filler wires. Design/methodology/approach A non-consumable tungsten electrode with a diameter of 1.6 mm was used during the GTAW procedure. The filler wire, ER316L, was selected based on the recommendation provided in literature. To explore the interconnections among the structure and properties of these weldments, the techniques including scanning electron microscopy and optical analysis have been used. In addition, the sensitization behaviour of the weldments was investigated using the double loop electrochemical potentio-kinetic reactivation (DLEPR) test. Findings Microstructural analyses revealed the occurrences of coarsened grains with equiaxed columnar grains and migrating grain boundaries in the weld zone. The results of the DLEPR test demonstrated that heat affected zone (HAZ) of AISI 430 was more susceptible to sensitization than HAZ of AISI 316L. Microstructure analysis also revealed the precipitation of large amounts of chromium carbide at the grain boundaries region of AISI 430 welded steel, causing more sensitization and, as a result, more failure or breaking at the side of AISI 430 weld in the dissimilar weldment of AISI 316L–AISI 430. Originality/value The present work has been carried out to determine the appropriate welding conditions for joining AISI 316L and AISI 430, as well as the metallurgical properties of the dissimilar weldment formed between AISI 316L and AISI 430. Owing to the difficulties in measuring the performance of these types of dissimilar joints given their unique mechanical and microstructural characteristics, research on the subject is limited.

On the Intergranular Corrosion Susceptibility of 304 Stainless Steel with Ultrafine Grains and Comparison with Micrometer Austenitic Grains Counterpart

The intergranular corrosion (IGC) susceptibility of ultrafine grains (∼430 nm) and micrometer grains (∼3.1 µm to 9.8 μm) 304 stainless steel obtained by cryogenic rolling and reversion annealing treatments were studied. Transmission electron microscopy results showed that after sensitized treatment at 650°C for 2 h, the micrometer grains were sensitized with many M23C6 precipitates at the grain boundaries, while no precipitates were in the ultrafine grains. The immersion corrosion tests in H2SO4-CuSO4 solution showed that ultrafine grains exhibited weaker IGC attacks than micrometer grains. The double-loop electrochemical potentiokinetic reactivation tests demonstrated the degree of sensitization decreased from 26.61% to 1.52% with the grain ultra-refinement from micrometer to ultrafine. Corrosion studies indicated that the ultrafine grains exhibited lower IGC susceptibility compared with micrometer grains. According to the findings, the large number of grain boundaries generated by grain ultra-refinement inhibited M23C6 precipitates at the grain boundaries during the sensitized process, thereby reducing the susceptibility of ultrafine grains to IGC.

Microstructure and electrochemical evaluation of ER-308L weld overlays on AISI 321 stainless steel for repair applications

Weld overlaying is a promising and economical solution for repairing stainless steel structures. The present work deals with the deposition of ER-308L weld overlays on AISI 321 plate with Robotic gas metal arc welding setup. Microstructural examination depicts the presence of dendritic structures (equiaxed and columnar) and ferritic stringers. Energy-dispersive X-ray analysis confirmed the absence of precipitates and phases susceptible to corrosion in the as-deposited weld overlays. Specimens from ER-308L (weld overlay) and ER-308L&321-SS (interface) regions were subjected to electrochemical analysis using the Potentiodynamic polarization and double-loop electrochemical potentiokinetic reactivation measurements. Both overlay and interface sections exhibited comparable corrosion rate – 3.30 and 3.62 mils penetration per year, respectively with different passivation behaviour. The improved passivation behaviour of the ER-308L weld overlay authenticates the presence of δ-ferrite stringers. Double-loop electrochemical potentiokinetic reactivation tests highlighted the absence of sensitization on both weld overlay and interface specimens. This study presents the initial assessment results for repairing structural steel components subjected to corrosion damage.

Corrosion behavior of wire arc additive manufactured and wrought 309 stainless steel in acidic solution

In this study, 309 stainless steel (309SS) was fabricated by wire arc additive manufacturing (WAAM) process and characterized using optical microscopy and X-ray diffractometry. Corrosion behavior of WAAM 309SS in 1 mol/L H2SO4 solution at room temperature was investigated in comparison to that of wrought 309SS using electrochemical impedance spectroscopy, pontentiodynamic polarization, and immersion test. Mott-Schottky analysis, double loop electrochemical potentiokinetic reactivation (DLEPR) test and galvanic corrosion test using zero resistance ammeter (ZRA) technique were also conducted. The results showed that WAAM 309SS exhibited lower corrosion resistance than AISI 309SS due to microstructural differences engendered by the additive manufacturing process. Galvanic corrosion test showed that galvanic effect between the two stainless steels was minimal despite the microstructural differences while DLEPR test revealed the absence of chromium-depleted zones in both WAAM 309SS and AISI 309SS.

Ferritic-induced high-alloyed stainless steel produced by laser powder bed fusion (L-PBF) of 2205 duplex stainless steel: Role of microstructure, corrosion, and wear resistance

Stainless steels are dominant in application where combination of corrosion and mechanical resistances are requested. They have gained scientific attention in additive manufacturing (AM) field, and stainless steel products produced by AM find use in a wide array of applications. This study aims to evaluate the microstructure, the wear and corrosion resistances of a high-alloyed ferritic-induced stainless steel (FSS) obtained by laser powder bed fusion (L-PBF), from a duplex stainless steel (DSS) precursor, SAF 2205, used to produce gas-atomized powders. No heat treatment was applied to the ferritic-induced L-PBF stainless steel to restore the duplex structure. The L-PBF FSS was dense and high alloyed with Cr, Mo, and N (pitting resistance equivalent number, PREn, ~33), presenting a negligible corrosion current density in the order of 10−7 A.cm−2, with an enlarged passivation window ~ 1.2 V with respect to the corrosion potential, restraining the current density at the passivation plateau below 10−4 A.cm−2. Also, double-loop electrochemical potentiokinetic reactivation (DL-EPR) tests indicated unsensitized L-PBF FSS, with negligible degree of sensitization caused by the cyclic heat input during building up of the specimen. Besides be corrosion-resistant, the L-PBF FSS was hard (290 HV0.5) and wear-resistant against sliding wear, with a reduced specific wear rate of 5 × 10−4 mm3·N−1·m−1. The corrosion resistance of the L-PBF specimen (almost fully ferritic microstructure) was comparable to its hot-rolled precursor that displayed a duplex microstructure, albeit slight inferior. The L-PBF FSS was harder and more wear resistant than the DSS precursor. These results point out to the formation of a new high-alloyed ferritic-induced stainless steel, which are corrosion-resistant in chloride-rich medium and wear resistant in sliding conditions.

Hydrogen stress cracking of Alloy 716 under cathodic protection—root cause analysis, and an evaluation of quality control methods

A subsea fastener made of Alloy 716 (UNS N07716) experienced a brittle fracture in service. The investigations described herein suggested that the failure was caused by hydrogen stress cracking (HSC), thus, adding to the number of reported HSC incidents on precipitation hardened nickel-based alloys over the last two decades. Incremental step loading testing on notched tensile specimens showed a net section threshold stress of <44% of the fastener materials actual yield strength. X-ray diffraction revealed that the grain boundary (GB) precipitates were predominantly the σ–related precipitate F-phase, which were suggested to have a detrimental effect on HSC resistance—even in low amounts. The low amounts of GB precipitates were indicated by a low degree of sensitization in the double-loop electrochemical potentiokinetic reactivation test. Two additional heats from the same alloy were investigated to elucidate the effect of different GB precipitates on HSC resistance and to evaluate quality control methods that are discussed in the research community.

Study of strain induced martensite and its reversal on sensitization behaviour of metastable austenitic stainless steel

PurposeThe purpose of the present study is to investigate the effects of strain-induced martensite (SIM) and its reversal on metastable austenitic stainless steel (MASSs) through the analysis of metallurgical and sensitisation behaviour.Design/methodology/approachIn the present investigation, the samples of Cr-Mn ASS (also known as MASSs) including 15%, 30% and 50% cold worked, solution annealed samples with and without thermal ageing (at 700°C for 3 h) were analysed with the help of X-ray diffraction analysis, microstructure examination and electrochemical behaviour. The scanning electron microscope (SEMJOEL 6380 A) was used to examine the microstructure of the sample, and the double-loop electrochemical potentiokinetic reactivation test was used to determine the degree of sensitisation (DOS) in the samples. The cold worked solution annealed samples without thermal ageing are named as CR15, CR30 and CR50, respectively, and the samples with thermal ageing are named as CR15_TA, CR30_TA and CR50_TA, respectively.FindingsIn CR15, CR30 and CR50 samples, the DOS increased with increase in the extent of cold working, which was attributable to passivation deterioration. Because of the high degree of passivation at the grain boundaries, the DOS of CR15_TA and CR30_TA were practically identical. The DOS in the CR50_TA sample, on the other hand, was lowered due to SIM recovery in the austenite.Originality/valueThe present study sheds light on how to choose the right cold working percentage to avoid sensitisation in MASSs during the fabrication of metal forming components.

Effect of thermomechanical processing via rotary swaging on grain boundary character distribution and intergranular corrosion in 304 austenitic stainless steel

In the present work, the thermomechanical processing consisting of rotary swaging deformation and annealing treatment was performed to optimize the grain boundary character distribution (GBCD) of 304 austenitic stainless steel. To systematically investigate the effect of GBCD evolution on intergranular corrosion (IGC), double loop electrochemical potentiokinetic reactivation and electrolytic oxalic acid etch tests were employed. The experimental results show that the fraction of low-Σ coincident site lattice (CSL) boundaries increased from 58.1% to 74.0% for the specimen swaged to 0.06 true strain and then annealed at 1050 °C for 5 min duration. By characterizing the evolution of GBCD as a function of strain level in terms of low-Σ CSL boundaries fraction, average twin-related domain (TRD) size, average number of grain per TRD and fractal dimension of the maximum random boundary connectivity, the grain boundary engineering (GBE) microstructure was realized by the occurrence of prolific multiple twinning events during strain-induced boundary migration while static recrystallization has a detrimental effect on optimizing GBCD for the prolific of new strain-free grains with random boundaries. The IGC resistance of the GBE-treated 304 austenitic stainless steel is enhanced by inhibiting the nucleation and propagation of IGC cracks, resulting from the increase in the fraction of low-Σ CSL boundaries, especially Σ3 boundaries and the disruption of random boundary network connectivity.

Mitigating the susceptibility to intergranular corrosion of alloy 625 by friction-stir welding

In this work, friction-stir welding (FSW) was employed to alloy 625 grade I (soft annealed) sheets. Therefore, solid-state based welding was undertaken with a tool rotational speed of 200 rpm and a welding speed of 1 mm/s. Microstructural features were analyzed by light optical and scanning electron microscopy (LOM and SEM). Moreover, microhardness measurements were performed. The susceptibility to intergranular corrosion was verified by the double-loop electrochemical potentiokinetic reactivation (DL-EPR) test. Complementary, intergranular corrosion was also evaluated by the ASTM G28 Method A. FSW promoted grain refinement, increased microhardness, and reduction in the degree of sensitization. Finally, the mean corrosion rate observed in the ASTM G28 Method A test was 0.4406 mm/year, which suggests a good weld quality.

Some aspects of pitting corrosion susceptibility of As‐welded and thermally aged nitrogen‐alloyed 316SS weld metal

AbstractType 316N (0.07% N) stainless‐steel welds prepared by shielded metal arc welding were evaluated for their pitting corrosion susceptibility in an acidified chloride environment and a neutral chloride environment in as‐welded and thermally aged conditions at 823 and 923 K for 4, 10, 24, and 100 h. After 100 h thermal aging at 823 K, 46% of δ ferrite was transformed into carbide and 81% δ ferrite was transformed into carbide and sigma phases at 923 K for 100 h. On thermal aging at 823 K (0–10 h) and 923 K (10–100 h), the changes in the degree of alloy depletion (DOA) and pitting potential were marginal due to the presence of nitrogen. Thermally aged samples at 823 K beyond 24 h showed a significant decrease in pitting potential in acidic and neutral chloride media, whereas at 923 K, the pitting potential decreased significantly up to 10 h. The results of DOA and passive current density from the double‐loop electrochemical potentiokinetic reactivation (DLEPR) test and the electrochemical reactivation test (ERT) correlated well with the observed secondary phases. The role of alloy depletion in terms of the parameters DLEPR, ERT, microstructure, and nitrogen alloying on pitting corrosion is discussed.

DL‐EPR and AFM study of sensitization of a 17%Cr multiphase stainless steel

AbstractThe corrosion behavior of a 17Cr multiphase martensitic stainless steel quenched (1000°C, water cooling) and tempered at different temperatures was determined using the double‐loop electrochemical potentiokinetic reactivation (DL‐EPR) test. The specimen tempered at 550°C showed the highest degree of sensitization. For the specimen treated at 600°C, a healing process was observed, followed by a second sensitization at 625°C coincident with an increase in the austenite volume fraction. This phase was quantified using the magnetic method and an increase in this phase was observed with the tempering temperature. The DL‐EPR results were correlated with surface aspects obtained by atomic force microscopy.

The Effect of Reversion of Strain-Induced Martensite (SIM) and Grain Refinement on the Intergranular Corrosion of High Mn Steel

The surface phase constituent of high-manganese austenitic stainless steel after cold work (15%, 30%, and 50%) and thermal aging at 900°C for 30 min and 6 h, was characterized using x-ray diffraction. The microstructural analysis was conducted using an optical microscope, a scanning electron microscope, and the electron backscatter diffraction technique. The double-loop electrochemical potentiokinetic reactivation test was used to measure the intergranular corrosion resistance (degrees of sensitization). The results showed that fine-recovered grains of austenite and strain-induced martensite together formed the surface of high-manganese steel after cold work. Because of the formation of strain-induced martensite in the cold-worked samples, their intergranular corrosion was much higher than that of the as-received sample. Also, the degree of sensitization of 15% cold work was higher (i.e., more intergranular corrosion) compared to the degrees of sensitization of 30% and 50% cold work. On the contrary, the intergranular corrosion of high-manganese austenitic stainless steel sample subjected to cold work was eliminated during thermal aging at 900°C for 6 h because of the reversion of strain-induced martensite and fine-reverted austenite grains. Owing to this grain refinement of austenite, faster diffusion rate of Cr at higher temperature and cold work helped healing of Cr-depletion zone in a shorter time. In other words, because the results showed that on 50% cold work and thermal aging at 900°C for 6 h, the high-manganese austenitic stainless steel does not become susceptible to intergranular corrosion. Hence, it could be beneficial to investigate the intergranular corrosion of high-manganese austenitic stainless steel.

Effect of filler and autogenous welding on microstructure, mechanical and corrosion properties of low nickel Cr-Mn ASS

ABSTRACT This experimental study investigates the effects of welding low nickel Cr-Mn austenitic stainless steel with gas tungsten arc welding process with and without filler (autogenous) weld by varying the welding currents (120A, 130A and 140A). The microstructural examination of weld has been carried out with optical microscope and mechanical properties with Vickers microhardness and tensile tester. The corrosion behaviour of the welded joints are analysed by double loop electrochemical potentio-kinetic reactivation test to obtain degree of sensitisation. The microstructural examination of welded joints revealed that, as the welding current increases, the inter-dendritic spacing as well as the dendrite size increases. The tensile strength and hardness decrease with increasing welding current for 308 L filler and autogenous weld. The degree of sensitisation increases with increasing welding current for both the welds. The results reveal that the autogenous welds have higher tensile strength, higher hardness and lower degree of sensitisation as compared to welds with 308 L filler.

Reductions of Intergranular Corrosion Resistance and Wear Resistance in a Ni-Cr-Mo-Based Superalloy by Aging-Treatment-Induced Precipitation

Ni-Cr-Mo-based superalloy is widely used as a key component in many critical environments. To ensure that the manufacturing process does not impact the long-term service performance of these components, the aging precipitation behavior at different temperatures and its effect on intergranular corrosion (IGC) resistance and wear resistance of a Ni-Cr-Mo-based C276 superalloy were investigated. The equilibrium phase diagram was calculated first using thermodynamic software to confirm the potential phases. Carbides of M6C were found to be formed at grain boundaries after aging at 800–850 °C for short-term treatment. The other two phases (μ phase and P phase) indicated in the phase diagram were not observed for the samples after aging treatment up to 15 h. Furthermore, double loop electrochemical potentiokinetic reactivation (DL-EPR) tests were conducted to examine the IGC resistance. The degree of sensitization increased with the aging time and severe corrosion was found to occur at grain boundaries. For the first time, the influence of aging treatment on the wear behavior of this superalloy has been specifically studied. Concerning the hot processing of Ni-Cr-Mo-based C276 superalloy, these results indicate the importance of avoiding high-temperature heat treatment for long periods.

Effect of number of welding passes on the microstructure, mechanical and intergranular corrosion properties of 409M ferritic stainless steel

PurposeThis paper aims to study the effect of number of welding passes on microstructure, mechanical and corrosion properties of 409 M ferritic stainless steel. Shielded metal arc welding (SMAW) process is used to weld two metal sheets of 409 M having 3 mm thickness as bead-on-plate with single, double and triple passes. Microstructures were observed at transverse section with the help of optical microscope and with increasing number of passes grain growth, and the width of heat-affected zone (HAZ) increases. The results of tensile tests revealed that as number of passes increases, there is reduction in tensile strength and ductility. Double loop electrochemical potentiokinetic reactivation (DL-EPR) test revealed that as number of passes increases, the degree of sensitization increases. This is due to the deposition of chromium carbides at the grain boundaries and the associated depletion of chromium.Design/methodology/approachThree welded plates of single, double and triple pass were welded by SMAW process. From three welded plates (single, double and triple passes), samples for microstructural examination were cut in transverse direction (perpendicular to welding direction) with the help of wire-cut electrical discharge machine (EDM). The welded plates were sliced using wire-cut EDM along transverse direction for preparing optical microscopy, tensile testing, microhardness and DL-EPR testing specimens.FindingsFrom the microstructure, it was observed that the large grain growth, which is dendritic, and the structure become finer to increase in number of welding passes. As number of passes increases, the width of HAZ increases because of the higher temperature at the welded zone. The tensile strength decreases to increase the number of welding passes because of grain coarsening and chromium carbide precipitation in sensitized zone and wider HAZ. The maximum microhardness value was observed for single-pass weld as compared to double- and triple-pass welds because of the fast cooling rate. The degree of sensitization increases to increase the number of passes because of chromium carbide deposition at the grain boundaries.Originality/valueThe authors declare that the manuscript is original and not published elsewhere, and there is no conflict of interest to publish this manuscript.

Detecting Intergranular Phases in UNS N07725: Part I. Adapting the Double-Loop Electrochemical Potentiokinetic Reactivation Test

Precipitation hardened nickel-based Alloy 725 (UNS N07725) has been proven susceptible to hydrogen embrittlement in oil and gas production. Moreover, current standards cannot differentiate unequivocally between acceptable and affected microstructures, making the development of an appropriate quality control test a priority for the oil and gas industry. Recently, Alloy 725 failures were associated with the precipitation of nanoscale Cr- and Mo-rich phases at grain boundaries (GBs). Since these intergranular precipitates could lead to Cr- and Mo-depletion along the decorated GBs (i.e., sensitization), the double-loop electrochemical potentiokinetic reactivation (DL-EPR) test was explored as an alternative approach to detect affected microstructures. Herein, the DL-EPR technique was optimized for Alloy 725 by testing three types of samples with different degrees of sensitization, including a full GB-decorated microstructure that was shown prone to hydrogen embrittlement in oil and gas service. The optimized DL-EPR test conditions were 2 M HCl + 1 M H2SO4 + 10−4 M KSCN aqueous solution at 30 °C with a 1.667 mV s−1 scan rate and a vertex potential of Ecorr + 700 mV. Results were reproducible and consistent with the degree of GB decoration determined using metallographic methods. The test procedure developed herein could lead to the standardization of the DL-EPR method for Alloy 725.

Detecting Intergranular Phases in UNS N07725. Part II: Double-Loop Electrochemical Potentiokinetic Reactivation Test Validation

The formation of interconnected grain boundary (GB) phases in precipitation hardening (PH) nickel Alloy 725 (UNS N07725) compromises its mechanical properties and has been linked to hydrogen embrittlement failures. However, normative industry standards such as API 6ACRA are inadequate for differentiating between Alloy 725 batches with a critical extent of GB precipitation, creating the need for a complementary qualification method.In Alloy 725, intergranular phases produce a Cr and Mo depletion adjacent to GBs (i.e., sensitization). In Part I of this work, this impoverishment in Cr and Mo was used as the basis to develop a double-loop electrochemical potentiokinetic reactivation (DL-EPR) test, optimized to quantify the extent of GB precipitation in Alloy 725. Part II explores the reproducibility and sensitivity of the new approach using three new independent commercial batches containing different extents of precipitation. Results were highly reproducible and confirmed the method’s sensitivity to detect small amounts of GB phases. Additionally, the DL-EPR procedure revealed clear microstructural inhomogeneities across the bars’ thickness, which increased with increasing bar diameter. This investigation strongly supports the validity of the new DL-EPR technique as a reliable and straightforward industry-friendly qualification method to quantify the extent of intergranular phases in Alloy 725.

Effect of Fillers and Autogenous Welding on Dissimilar Welded 316L Austenitic and 430 Ferritic Stainless Steels

This experimental study examines the effects of dissimilar welding of 316L austenitic and 430 ferritic stainless steels, welded with gas tungsten arc welding process with (ER316L and ER309L) and without fillers (autogenous). Microstructural examination was performed by optical and scanning electron microscopy. ER316L and ER309L fillers welds illustrated equiaxed and columnar grains; ER309L weld showed higher Creq/Nieq ratio than that of ER316L weld, produced vermicular ferrite, while autogenous weld shows lathy ferrite and martensite. Chromium carbide precipitate was also observed in autogenous weld. The mechanical properties were measured and higher hardness was obtained in autogenous weld compared to ER316L and ER309L filler weld. Higher tensile and impact strength was measured in ER316L filler weld as compared to ER309L filler and autogenous weld. The corrosion resistance of the joints was carried out by double loop electrochemical potentiokinetic reactivation and potentiodynamic polarization test to assess the sensitization and pitting resistance, respectively. Higher degree of sensitization and pitting were observed in autogenous weld as compared to ER316L and ER309L filler weld due to precipitation formation, but the pitting corrosion was found to be lower for ER309L filler weld as compared to ER316L filler and autogenous weld due to the effect of mode of solidification.