High Chromium Content Research Articles

Advances in Water Resource Management: An In Situ Sensor Solution for Monitoring High Concentrations of Chromium in the Electroplating Industry

Concerning environmental safety and mitigating the risk of water pollution, the electroplating industry, historically reliant on the use of elevated concentrations of heavy metals to achieve high-quality products, faces a crucial challenge in monitoring wastewater enriched with these metals, notorious for their adverse effects on ecosystems and human health. Chromium, in both oxidation states Cr (III) and Cr (VI), emerges as a prominently employed metal, yielding noteworthy outcomes throughout the galvanisation process. This research showcases the prototype of an automatic in situ sensor tailored to industry sustainability efforts to facilitate real-time monitoring and efficient water management. This custom sensor, characterized by sensitivity, reliability, and user-friendliness, utilizes UV-Vis colorimetric principle to detect Cr in both oxidation forms ranging from grams per litre (g/L) to parts per million (ppm). This is made possible by the unique vibrant colours induced by chromium ions, enabling the precise measurement of analyte concentrations. Thanks to 3D printing, this sensor system interacts with customized parts, designed and validated through simulation processes, for filtering out particulate that may interfere with the analysis. The outcome represents a synergistic blend of technology and environmental responsibility, aligning industrial processes with the goal of safeguarding water resources and ecosystems.

CO–H2 Gas-Based Reduction Behavior of Cr-Rich Electroplating Sludge Mixed with Iron Ore Powder

Cr-rich electroplating sludge (CRES) is a complicated solid waste with high contents of chromium and iron. It can be used as a main feed of the FINEX ironmaking process, which requires gas-based reduction before smelting reduction to produce molten iron with the proper addition of iron ore powder. In this study, the CO–H2 gas-based reduction behavior of CRES mixed with iron ore powder was evaluated between 700 °C and 850 °C, with a focus on the variations of key components containing Fe, Cr, and S with reduction temperature and time. It was found that the iron oxides in CRES had stepwise conversions to metallic iron as the reduction reaction proceeded. The iron metallization degree of the mixture of CRES and iron ore powder increased obviously below 750 °C and then grew minorly with the further increase of temperature. Moreover, this index varied similarly with an extension of reduction time up to 80 min. After reduction at 750 °C for 60 min with the volume concentration of H2 of 30% and flow rate of 160 mL/min, the iron metallization degree reached 79.08%. The rate in the process was limited by a chemical reaction with an activation energy of 41.32 kJ/mol. Along with the stepwise reduction of iron oxides to metallic iron, the chromium hydroxide and sulfates in CRES were reduced to Cr2O3 and sulfites and sulfides, respectively.

Serpentine environment prevails over geographic distribution in shaping the genetic diversity of Medicago lupulina L.

Edaphic conditions of serpentine soils, naturally rich in heavy metals, act as a strong selection pressure that shapes specific metal-tolerant ecotypes. Medicago lupulina L. (black medick) is not only a widespread plant species that prefers calcareous and dry soil types but also grows at the borders of serpentine formations. It can also be found in waste and disturbed habitats. This is a species with reported phytoremediation potential, however, there is no published data regarding the impact of the environment on the genetic distribution of this species. The aim of our research was to explore how selection pressure of serpentine soils affects genetic diversity of M. lupulina and to test heavy-metal accumulation capacity of this species. Specimens of 11M. lupulina populations were collected from serpentine outcrops located in Central and Eastern Bosnia as well as from non-serpentine sites. Soil and plant samples were analyzed for the total contents of heavy metals using air-acetylene flame atomic absorption spectroscopy. Genetic diversity was analyzed using AFLP (Amplified Fragment Length Polymorphism) markers. Serpentine soils showed high nickel, cobalt, chromium and iron concentrations. Nickel and manganese concentrations in soil samples and plant material showed statistically significant correlation. Although plants in two populations show the ability to extract Ni, M. lupulina does not show hyperaccumulating properties. Despite severe selective pressure, genetic diversity in serpentine populations is not reduced. Analyses of intrapopulation and interpopulation genetic diversity showed significant genetic differentiation among populations which is not related to their geographic distance. Population from non-metalliferous soil showed clear separation from all other populations. Diversity data suggest that serpentine populations maintain genetic diversity by undetected mechanisms and that edaphic factors rather than geography influence genetic structure analyzed M. lupulina populations.

Assessment of Metal Concentration and Bioaccumulation Factor in Surface Water and Fishes Sampled From Four Creeks in the Bonny River Estuary, Niger Delta Region of Nigeria

The indiscriminate disposal of industrial and urban waste has added to the concerns of global water pollution. Anthropogenic activities and activities of oil companies (oil spills) have also contributed to the pollution of the aquatic ecosystem in the Niger Delta region of Nigeria. This study was therefore designed to evaluate the concentration of Iron, Nickel, Lead, Cadmium and Chromium in our surface waters and our marine life. Samples of surface water were collected into 50 cl sterile plastic bottles and labelled accordingly. Twenty medium-sized tilapia fishes from about a one-kilometre radius of each site were caught and also labelled accordingly. Water and fishes from each site were then kept in a cooler, iced and immediately transported to the laboratories for analysis for heavy metals after these fishes were homogenised using a blender. Atomic absorption spectrophotometer was used for the metal analysis. Standards were prepared using tracecert of each of the above-mentioned metals. The results of these study sites (Akpajo, Okujagu, Woji and Elelenwo) had high concentrations of metals. Fishes from all these sites also had high concentration of these metals. The trend of metal concentration in the surface water as follows: Okujagu–Pb>Cr> Cd>Fe = Ni, Akpajo–Cd>Fe>Pb>Cr>Ni, Elelenwo–Pb>Cr>Fe>Cd>Ni, Woji–Cr>Cd>Pb>Fe>Ni. Results obtained also revealed the trend of metal concentration in fish muscles as follows: Okujagu–Pb>Cr> Cd>Fe = Ni, Akpajo– Cd>Fe>Pb>Cr>Ni, Elelenwo–Pb>Cr>Fe>Cd>Ni and Woji–Cr>Cd>Pb>Fe>Ni. Fishes and surface water sampled from these four creeks in the Bonny estuary in the Niger Delta region of Nigeria had high concentrations of iron, nickel, cadmium, chromium and lead in relation to their concentration in surface water. The results of this study revealed that metal concentration in surface water had some relative effect on their concentration in the fishes. This, therefore, means consumption of these fishes may lead to the accumulation of these metals in man to a toxic concentration. This may be one of the reasons for the increase in some heavy metal-related health issues (diabetes, renal diseases) in this region.

Water Quality Assessment and Heavy Metal Levels in Mudskipper (Periophthalmus Papilio), Sediments and Water of Mangrove Swamps, Rivers State, Nigeria

A study was conducted to determine the physicochemical parameters of surface water and heavy metal concentrations in the mudskipper (Periophthalmus papilio) fish, sediments, and water collected from the Ikpukulu, Kalio, and Ogoloma swamps of Okrika Local Government Area, Rivers State, Nigeria and analysed using standard methods. All samples were collected for six months from three stations in 2023. The results indicate that pH and temperature values were significantly lower across stations in terms of physicochemical properties than standards. However, there was a significant increase in electrical conductivity, total dissolved solids, and salinity. Ikpukulu had the highest EC (1917 uS/cm), while Kalio had the highest salinity (333.3 ppm). All stations had significant decreases in dissolved oxygen (DO) and biological oxygen demand (BOD), with Ogoloma having the lowest values (DO: 3.2 mg/L, BOD: 2.9 mg/L). Copper and chromium levels were significantly higher than the standards in all stations, while cadmium levels were not significantly different from those in the standards. As compared with the standards, copper levels in water samples were considerably higher, especially in Ogoloma (2.03 mg/kg). Ogoloma had a higher concentration of chromium. Cadmium levels decreased significantly at all stations for the mudskipper (P. papilio). The copper levels in Ogoloma and the chromium levels in Ikpukulu were significantly higher than those in standards. The results of the study suggest an increase in heavy metal concentrations in the mangrove swamp region, emphasising the need for proactive measures to mitigate activities that may adversely affect the aquatic ecosystem and the communities that depend on it.

Quantification of secondary ion mass spectrometry measurements by using ion‐implanted metallic standards

This research addresses an analytical methodology to quantify elements of interest in fusion‐relevant materials using secondary ion mass spectrometry (SIMS). For this purpose, internal standards have been fabricated by ion implantation to avoid the well‐known matrix effect of this technique. In particular, chromium has been implanted at an energy of 12 MeV using two fluences in high‐purity iron and tungsten matrices together with Si control substrates. The latter were applied to determine the Cr concentration implanted through experimental and semiempirical methods. Specifically, the IBA technique Rutherford backscattering spectrometry (RBS) provided the quantitative results being 3.1 × 1019 at/cm3 and 1.6 × 1019 at/cm3 for the high and low dose, respectively. The SIMS depth profiles of Cr for the Fe and W matrices established an ion implantation depth close to 2 μm on both substrates in agreement with the calculations previously performed by Stopping and Range of Ions in Matter (SRIM) simulations. Correlation between the integration of SIMS profiles and known concentrations of the implanted ion resulted in the calibration curve for each matrix, obtaining the SIMS quantification approach by means of this relative sensitivity factor (RSF). Additionally, a cross‐check of the method by comparing commercial Fe‐Cr alloys with the Cr‐implanted Fe matrices of the present study pointed out the need to produce standards with higher chromium concentrations.

Characterization of heavy metal-associated bacteria from petroleum-contaminated soil and their resistogram and antibiogram analysis.

The aim of the current study was to screen and identify heavy metal (chromium, cadmium, and lead) associated bacteria from petroleum-contaminated soil of district Muzaffarabad, Azad Jammu and Kashmir, Pakistan to develop ecofriendly technology for contaminated soil remediation. The petroleum-contaminated soil was collected from 99 different localities of district Muzaffarabad and the detection of heavy metals via an atomic absorption spectrometer. The isolation and identification of heavy metals-associated bacteria were done via traditional and molecular methods. Resistogram and antibiogram analysis were also performed using agar well diffusion and agar disc diffusion methods. The isolated bacteria were classified into species, i.e., B. paramycoides, B. albus, B. thuringiensis, B. velezensis, B. anthracis, B. pacificus Burkholderia arboris, Burkholderia reimsis, Burkholderia aenigmatica, and Streptococcus agalactiae. All heavy metals-associated bacteria showed resistance against both high and low concentrations of chromium while sensitive towards high and low concentrations of lead in the range of 3.0 ± 0.0mm to 13.0 ± 0.0mm and maximum inhibition was recorded when cadmium was used. Results revealed that some bacteria showed sensitivity towards Sulphonamides, Norfloxacin, Erythromycin, and Tobramycin. It was concluded that chromium-resistant bacteria could be used as a favorable source for chromium remediation from contaminated areas and could be used as a potential microbial filter.

Microstructural characterization of 15Cr steel after quenching and slow cooling rates

Abstract Ferritic 15 %-Cr steels have better oxidation resistance, due to their higher chromium content, and creep strength, their lower dislocation density and lack of lath microstructure than conventional martensitic steels such as MarBN. Their mechanical properties are sensitive to chemical composition and heat treatment. In this study, we first simulated the formation of stable phases in two ferritic steels containing 2 % nickel (wt.%) and an alloy without nickel using the thermomechanical software MATCALC. Microstructural analysis using scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) reveals the formation of carbides and intermetallic phases after diffusion annealing, both during rapid cooling in oil and slow cooling in the furnace. Dilatometry and XRD studies confirm the gradual phase transformation of ferrite to austenite from 650 °C onwards during heating. Dilatometry also shows that ferritic steels have a lower coefficient of thermal expansion than martensitic steels, austenitic steels, and superalloys, which results in lower thermal stresses during frequent start-up and shutdown of power plants.

Antioxidant Minerals Modified the Association between Iron and Type 2 Diabetes in a Chinese Population.

Inconsistent findings exist regarding the relationship between heme iron intake and type 2 diabetes (T2D) among Western and Eastern populations. Easterners tend to consume a plant-based diet which is abundant in antioxidant minerals. To examine the hypothesis that antioxidant mineral may modify the relationship between iron and T2D, we performed a case-control study by measuring the serum mineral levels in 2198 Chinese subjects. A total of 2113 T2D patients and 2458 controls were invited; 502 T2D patients and 1696 controls were finally analyzed. In the total population, high serum iron showed a positive association with T2D odds (odds ratio [OR] = 1.27 [1.04, 1.55]); high magnesium (OR = 0.18 [0.14, 0.22]), copper (OR = 0.27 [0.21, 0.33]), zinc (OR = 0.37 [0.30, 0.46]), chromium (OR = 0.61 [0.50, 0.74]), or selenium concentrations (OR = 0.39 [0.31, 0.48]) were inversely associated with T2D odds. In contrast, in individuals with higher magnesium (>2673.2 µg/dL), zinc (>136.7 µg/dL), copper (>132.1 µg/dL), chromium (>14.0 µg/dL), or selenium concentrations (>16.8 µg/dL), serum iron displayed no association with T2D (p > 0.05). Serum copper and magnesium were significant modifiers of the association between iron and T2D in individuals with different physiological status (p < 0.05). Our findings support the idea that consuming a diet rich in antioxidant minerals is an effective approach for preventing T2D.

Evaluation of Cr(VI) Removal from Tanning Effluents Using Magnetic Nanoparticles of Fe3O4 Synthesized with Olea europaea Bone Extract.

The tanning industry generates effluents with high chromium content, which require treatment prior to discharge into the sewage system. This article explores the use of magnetic magnetite nanoparticles (MNPs) to remove Cr(VI) from aqueous solutions, such as tanning effluents. The MNPs were synthesized by coprecipitation reaction using the Olea europaea extract as a reducing agent. Subsequently, they were characterized by dynamic light scattering spectroscopy (DLS), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). MNPs with irregular morphology and diameters ranging from 73.28 to 162.90 nm were obtained. Cr(VI) removal was performed using jar test methodology, and its efficiency was evaluated in the laboratory for different initial Cr(VI) (mg/L) concentration and nanoparticle (g/L) concentration. A kinetic study was developed and indicated that the equilibrium adsorption mechanism corresponds to a pseudo-second-order model. Furthermore, the isotherm analysis revealed that chromium adsorption best fits the Langmuir isotherm. Finally, Cr(VI) removal rates from 85% to 100% were achieved in tanning and retanning effluents.

Evaluation of weldability of nickel-base alloy weld materials with high chromium content

Evaluation of weldability of nickel-base alloy weld materials with high chromium content

Determination of the level of chromium (III) and comparison of chemical precipitating agents to recover and reuse it from tannery waste water

Most tannery wastes are discharged into the natural environment without any treatment system and pose a potential negative impact on living things due to their high organic loading and chromium content. In this study, a comparison of chemical precipitating agents to recover and reuse chromium (III) from tannery waste water was done. The study was conducted by performing physicochemical characterization and chemical precipitation. The Cr concentration was determined using the flame atomic absorption spectroscopy (FAAS) method. Statistical analysis was performed using the SPSS program through one-way analysis of variance (ANOVA). In terms of sludge volume, magnesium oxide produced 25%, calcium hydroxide 31%, and sodium hydroxide 44%. The findings have implications for global sustainability, as the use of magnesium oxide as a precipitating agent results in a smaller sludge volume and potentially less environmental impact.

Physiological and Morphological Response of Heavy Metal Stress in Vigna mungo (L.) Hepper

Introduction: Heavy metals such as manganese (Mn), magnesium (Mg), chromium (Cr), and nickel (Ni) negatively impact plant growth and productivity. Understanding plant responses to heavy metal stress is crucial for developing strategies to mitigate these effects in agriculture. Aim/Objectives: This study aims to investigate the impact of various heavy metals (Mn, Mg, Cr, and Ni) on the physiological and morphological responses of Vigna Mungo (L.) Hepper. Key objectives include evaluating the effects of different concentrations of these heavy metals on plant growth, productivity and photosynthetic efficiency. Method/Materials: A field experiment was conducted using a series of pots filled with soil, treated with different concentrations of MnCl2 , MgSO4 , Cr2 O3 , and Ni. Control samples without heavy metals were also maintained. Key parameters, including plant height, number of branches, number of pods, pod length, fresh and dry weight of pods, number of seeds per pod, weight of 100 seeds, root nodules, and chlorophyll content, were recorded and statistically analysed. Results: Heavy metal stress significantly inhibited plant growth and productivity, with decrease in plant height, number of branches, pods per plant, pod length, fresh and dry pod weight, and seeds per pod. High chromium concentrations prevented pod formation. Root nodules decreased, affecting nitrogen fixation. Chlorophyll content decreased in Mn, Ni, and Mg-treated plants but unexpectedly increased at higher Cr concentrations, indicating complex interactions with chlorophyll synthesis. Discussion: The findings show that heavy metal stress significantly inhibits plant growth and productivity, consistent with previous studies. Symptoms such as stunting, and chlorosis indicate disruptions in metabolic processes. This study underscores the need to monitor and manage heavy metal levels in agricultural soils to protect crop health and productivity. Developing soil remediation strategies and heavy metal-tolerant plant varieties is crucial for sustainable agriculture. Further research is needed to understand plant responses to heavy metal stress and enhance plant tolerance.

Electrospark deposition of Fe–Cr–Cu coatings on St3 steel

It is well-known that chromium in metallic compositions forms dense passivating films that slow down corrosion. The new Fe–Cr–Cu coating was applied on St3 steel through electrospark deposition in an anode mixture consisting of copper and titanium granules, with the addition of chromium powder ranging from 4.85 to 13.26 wt. %. The weight gain of the cathode increased nearly twofold with the addition of chromium powder to the anode mixture. The structure of the coatings was analyzed through X-ray phase analysis, scanning electron microscopy, and energy dispersive spectrometry. The phase composition of the coatings consists of ferrochrome and copper. It is demonstrated that the proposed method of electrospark processing allows for the creation of Fe–Cr–Cu coatings with an average chromium concentration ranging from 55 to 83 at. %. The average copper content in the prepared coatings varied from 5 to 16 at. %. The highest concentration of chromium was observed in the coating prepared with the addition of 13.26 wt. % Cr to the anodic mixture. The corrosion behavior of the coatings was investigated using potentiodynamic polarization and impedance spectroscopy in a 3.5 % NaCl solution. Polarization tests have shown that applying Fe–Cr–Cu coatings to St3 steel can increase its corrosion potential by 12 to 19 % and reduce the corrosion current by 1.5 to 3.4 times. The microhardness of the coating surface ranged from 3.08 to 4.37 GPa, and the coefficient of friction ranged from 0.75 to 0.91. The maximum hardness and the lowest coefficient of friction were observed in the coating with the highest chromium content. It has been demonstrated that Fe–Cr–Cu coatings can enhance the wear resistance of the surface of St3 steel by 1.5 to 3.8 times.

Redox control of chromium in the red soils from China evidenced by Cr stable isotopes

With chromium isotopes, we study the intricate dynamics of adsorption and redox processes in soil ecosystems, focusing on chromium's behaviour, in red soil profiles enriched with iron-manganese nodules (FMNs) in South China. Key findings reveal that the primary geological source of chromium in the red soil profiles is the weathering of colluvium parent minerals. FMNs have higher chromium concentrations (325–1451 µg/g) compared to surrounding soils (95–247 µg/g) and display stable δ53Cr values (0.78 ± 0.17‰), indicating their role as stable chromium repositories, reflecting historical processes. Furthermore, by isolating chromium associated with iron oxides (FeO) and silicate minerals (ReS) within FMNs and surrounding soils using CBD extractions, we show that FeO predominantly carry chromium, particularly in FMNs. The δ53Cr values of FeO fractions consistently exhibit heavier signatures than ReS fractions, suggesting the sequestration of isotopically heavy chromium (VI) during Fe oxide precipitation. Fluctuations in soil’s redox, rather than land use, play a pivotal role in controlling the precipitation of Fe oxides in surrounding soils and the formation of FMNs, thus influencing chromium mobility. This highlights the significance of these factors when utilizing chromium isotopic techniques for source tracking in soil systems, contributing to our understanding of chromium's behaviour in soil environments.

Evaluation of renal function in precarious workers exposed to heavy metals in vulnerable scenarios in the metropolitan area of San Luis Potosí, México

The aim of the study was to evaluate renal function in three groups of precarious workers: garbage recyclers (REC), quarry workers (CAN), and brick makers (LAD). Samples of urine and blood were collected to evaluate clinical parameters and the metal levels in urine was measured using ICP-MS. REC group had the highest concentrations of chromium in urine (36.03 ± 27.2 µg/l) compared to CAN and LAD groups. Mercury concentrations were higher in the LAD group (3.7 ± 0.8 µg/l). Additionally, arsenic was detected in both CAN and REC groups (25.4 ± 26.2 and 19.09 ± 16.7 µg/l, respectively), while arsenic concentrations in LAD were higher (47.2 ± 30.8 µg/l). In kidney biomarkers, β2-microglobulin concentrations were higher in the REC group (87867 ± 115159.5 ng/g UCr). Similarly, cystatin-C concentrations were higher in the REC group (32795.61 ± 34965.8 ng/g UCr). The data suggests that precarious workers are exposed to heavy metals and have elevated protein levels that contribute to kidney damage.

Detection of Hexavalent Chromium Ion in Water by Optode Membrane

Chromium is a heavy metal that is often found as a water pollutant. High concentrations of hexavalent chromium (Cr(VI)) ion in nature are toxic and carcinogenic, so their presence in water needs to be monitored. Detection of heavy metals in water was carried out using an optical sensor membrane (optode). The optode was fabricated from cellulose triacetate polymer with plasticizers (oleic acid and acetophenone), aliquot 336, and the chromoionophore 1.5-diphenylcarbazide (DPC). The success synthesis of optode was evidenced by FTIR and SEM characterization. The optode performance produces a linear response in detecting Cr(VI) ion in the concentration range of 0.02-0.40 mg/L with an R2 of 0.9930, as well as the best conditioning at pH 3. The detection and quantitation limits are 0.0055 mg/L and 0.0165 mg/L. The sensitivity of the chromium optode was excellence, with a molar absorptivity value of 8.8303 × 106 M-1cm-1. The performance test results of the chromium optode were acceptable because they meet the specified requirements for minimum detection concentration value.

Beneficial and adverse effects of dam construction in canal tannery wastewater effluent with a high content of chromium in Hazaribagh, Bangladesh

BackgroundBlockage to divide downstream canals into upstream canals, into which tannery wastewater including a high concentration of trivalent chromium [Cr(III)] is directly discharged, has been constructed in Hazaribagh, a tannery built-up area in Bangladesh. However, there has been no study to verify the environmental significance of blockage construction for water pollution of Cr in nature. MethodsConsecutive fixed area monitoring for a total of 164 water samples collected outside and inside Hazaribagh from 2014 to 2023 was carried out to clarify the effects of stagnant and flowable canal water in the presence or absence of blockage on Cr(III) and hexavalent Cr [Cr(VI)] concentrations. ResultsSince pollution of Cr(III) and Cr(VI) in Buriganga River (outside Hazaribagh) was not serious, this study then focused on their pollution in canal water (inside Hazaribagh) in the nonblockage period, blockage construction period and blockage destruction period. As expected, the mean Cr(III) concentration in downstream canal water samples in the blockage construction period was more than 98% lower than that in the upstream canal water samples in the same period, while the concentrations were comparable in downstream and upstream canal water samples in the nonblockage period and blockage destruction period. Unexpectedly, the mean concentration of Cr(VI) in the upstream canal water samples in the blockage construction period was 38.6-fold and 3.3-fold higher than that in the downstream canal water samples and the Cr(VI) guideline value by the US-EPA, respectively. ConclusionThis study demonstrated for the first time not only a merit of decreased Cr(III) pollution but also a demerit of increased Cr(VI) pollution in stagnant water derived from blockage construction in natural environments. This bitter lesson obtained by the enclosure of Cr(III)-polluted water is globally applicable for water pollution of Cr(III), which is used in various industries including the leather industry.

Cold metal transfer welding of 316L/430 dissimilar stainless-steel welds

Purpose This paper aims to examine dissimilar joints for various applications in chemical, petrochemical, oil, gas, shipbuilding, defense, rail and nuclear industry. Design/methodology/approach This study examined the effects of cold metal transfer welding on stainless steel welds for 316L austenitic and 430 ferritic dissimilar welds with ER316L, ER309L and without (autogenous) fillers. The microstructural observation was done with an optical microscope. The mechanical test was done to reveal the strength, hardness and toughness of the joint. The electrochemical polarization tests were done to reveal intergranular and pitting corrosion in the dissimilar joints. Findings This microstructural study shows the presence of austenitic and ferritic phases with vermicular ferrite for ER309L filler weld, and for ER316L filler weld specimen shows predominately martensitic phase in the weld region, whereas the autogenous weld shows lathy ferrite mixed with martensitic phase. Mechanical test results indicated that filler welded specimen (ER316L and ER309L) has relatively higher strength and hardness than the autogenous weld, whereas ER316L filler weld exhibited the highest impact toughness than ER309L filler weld and lowest in autogenous weld. The electrochemical corrosion results displayed the highest degree of sensitization (DOS) in without filler welded specimen (45.62%) and lower in case of filler welded specimen ER309L (4.95%) and least in case of ER316L filler welded specimen (3.51%). The high DOS in non-filler welded specimen is correlated with the chromium carbide formation. The non-filler welded specimen shows the highest pitting corrosion attack as compared to the ER316L filler weld specimen and relatively better in ER309L filler welded specimen. The highest pitting corrosion resistance is related with the high chromium content in ER309L composition. Originality/value This experimental study is original and conducted with 316L and 430 stainless steel with ER316L, ER309 and without fillers, which will help the oil, shipbuilding and chemical industries.

Alloy Design Optimization of Stainless Steel's Performance and Environmental Impact Through Taguchi‐Based Grey Relational Analysis

The current work presents an optimization approach for improving stainless steel's performance and environmental impact. A Taguchi‐based grey relational analysis is used to determine the optimal alloy design of six stainless steels (304, 316L, 904L, 2304, 2205, 2507). The alloy design of a multivariable system (C, Mn, Cr, Ni, N, Mo, and Cu) is initially formulated based on the Taguchi orthogonal array. It combines the multiperformances (pitting corrosion resistance, proof strength, tensile strength, and greenhouse gas emissions) to determine a numerical score and suggests the optimal combination of alloy contents. The results are further analyzed using a range analysis to detect the significance of each alloy parameter and its level. The results show that nitrogen plays the most important role in determining the stainless steel's combined performance. Besides, the optimum alloy design consists of a high content of nitrogen, chromium, molybdenum, and copper combined with a low content of nickel. The study has a focus on proposing the systematic approach, Taguchi‐based grey relational analysis, to optimize the stainless steel's different mechanical properties with respect to environmental impact.