Austenitic Stainless Steel Electrode Research Articles

Experimental and Numerical Investigation on Ballistic Performance of Ultra High Hard Armour Steel Joints Welded Using Shielded Metal Arc Welding Process and Austenitic Stainless Steel Electrode

Experimental and Numerical Investigation on Ballistic Performance of Ultra High Hard Armour Steel Joints Welded Using Shielded Metal Arc Welding Process and Austenitic Stainless Steel Electrode

Corrosion behavior of austenitic stainless steel and nickel-based welded joints in underwater wet welding

Marine structures such as ports, bridges, pipelines, vessels, and platforms are an essential part of modern infrastructure, where the use of higher-strength steel provides savings in logistics and construction. However, the repair of higher-strength steels can be challenging, especially underwater. Wet shielded metal arc welding is the most widely used and least expensive method for underwater welding repairs, but is very susceptible to hydrogen-induced cracking. Thus, researchers and welding engineers aim to reduce the amount of hydrogen in the weld material. Recent success has been achieved through the use of austenitic welding consumables, such as austenitic stainless steel and nickel-based electrodes. The use of these consumables drastically reduces the amount of diffusible hydrogen in the weld metal. However, these austenitic materials usually have different corrosion potential as compared to the structural steel the weld beads are applied to. This creates the risk of severe galvanic corrosion. In the presented study, the corrosion behavior of welds created with austenitic stainless steel and nickel-based electrodes were studied. Samples were aged for 1.5 years in the Baltic Sea. Simultaneously, the effectiveness of corrosion protection systems such as coating and Impressed Current Cathodic Protection (ICCP) were evaluated. Localized corrosion occurred in the heat-affected zone when austenitic electrodes were used in the corrosive environment. The localized corrosion depth after 1.5 years in the Baltic Sea and in the salt spray layer was approximately 250 µm and 390 µm, respectively. The ICCP system and the use of a coating were effective in preventing localized corrosion. The low pitting corrosion density of 2.5 × 103 m−2 corresponds to grade A1 according to the standard and was found to be negligible as compared to the localized corrosion in the heat-affect zone.

Experimental and numerical investigation on optimization of welding parameters and prediction of temperature distribution during shielded metal arc welding of ultra high hard armor steel joints

In this investigation, Ultra-high Hard Armor (UHA) steel plate by Shielded Metal Arc Welding (SMAW) process using the Austenitic Stainless Steel (ASS) electrode. In the first part of this investigation, using the finite element method (FEM), thermal analysis parameters were optimized using bead on plate welds in software code, known as SYSWELD. In the second part, using optimized parameters, a coupled thermo-mechanical analysis on multipass welded fabrication was carried out. Weld thermal cycles were analyzed by simulation and compared with experimentally measured temperature profiles. A double ellipsoidal heat source model was used to simulate the SMAW process. The heating rate and cooling rate were calculated along with residual stresses. This range of heating and cooling rate resulted in untempered martensite in the heat-affected zone (HAZ), confirmed by microstructure analysis and hardness mapping. Good validation was found between the measured and simulated 2D model with a 4–10% variation. This study suggests that numerical simulation is the capable technique in understanding the thermal and mechanical properties that influence the welding of ultra-high hard armor steels joints.

Effect of Post-Weld Treatment on the Microstructure and Mechanical Properties of Austempered FeNiCr Steel Welded Joint

This study investigated isothermally treated FeNiCr structural steel welded joints. The base metal contains various phases which are dominated by a mixture of bainite and martensite. Joining this steel can be challenging since it has high carbon equivalent values and high hardness. Shielded metal arc welding (SMAW) with austenitic stainless-steel electrodes is used to avoid cold cracking. After the welding process, the samples were subjected to three various post-weld temperatures: 425°C, 475°C, and 525°C. From the tensile test results, the tensile strength of welded joint shows an increase as the temperatures increase. The highest value is reached for a joint sample which treated at 525°C, with a tensile strength of 680 MPa. Conversely, the highest elongation is obtained by the 425°C post-treated sample, which is 14%. The microstructure in the weld metal (WM) area shows a formation of δ-ferrite, whereas the HAZ and BM areas show the presence of bainite and martensite tempered phases with various plate densities, plate size, and plate shapes depending on its post-treatment temperatures, which then affect the value of the hardness.

Comparative study of hardfacing applications on structural steel surfaces to improve ballistic properties

The aim of this study was to develop plates resistant to ballistic limits by welding on S355JR steel plate with Fe-Cr-C and austenitic electrodes. A total of four different weld coated materials were prepared for ballistic testing. For these four different coatings, E Z Fe 14 (Fe 14), E Fe 16 (Fe16) hardfacing electrodes and E 18 8 Mn R 3 2 (307) austenitic stainless steel electrode were selected, respectively. The coatings were made in the electric arc welding machine, with two different coatings on the surface for each material. These are Fe 14 – Fe 14, Fe 16 – Fe 16, 307-Fe 14 and 307-Fe 16, as the first layer and the second layer, respectively. In all coatings, the welding current was kept constant at 150 A and the welding voltage was kept constant at 27 V. The microstructure, hardness, and ballistic properties of the hardfacing surfaces were investigated using scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD) to analyze the phases and components. The hardnesses of the hardfacing surfaces were determined by Vickers methods from the weld metal to the base metal. Ballistic tests were conducted according to NIJ Level III standards, firing 7.62 × 51 mm AP bullets from a distance of 10 m to calculate the effects of the bullets on the plates, the kinetic energy of the bullet, and the amount of energy absorbed by the plates. Welding for hard surface coating achieved with the combination of 307 - Fe 14 electrodes provides the highest ballistic limit velocity at 830 m/s, while the lowest limit is observed in the material welded with Fe16-Fe16 electrodes at 747 m/s. Fe-Cr-C electrodes were found to be effective as main or auxiliary components when designing armor plates. This study highlights the potential of hardfacing techniques to improve the ballistic properties of steel surfaces, with implications for the development of protective materials across various industries.

Nanostructures and Oxygen Evolution Overpotentials of Surface Catalyst Layers Synthesized on Various Austenitic Stainless Steel Electrodes

Nanostructures and Oxygen Evolution Overpotentials of Surface Catalyst Layers Synthesized on Various Austenitic Stainless Steel Electrodes

A Comparative Numerical Analysis on the Effect of Welding Consumables on the Ballistic Resistance of SMAW Joints of Armor Steel

In the present investigation, a comparative study of ballistic impact behavior of Armox 500T (base metal) and its weldments prepared by low hydrogen ferrite (weldment-1) and austenitic stainless steel (weldment-2) consumables against 7.62 AP bullet has been performed with the help of finite element analysis code Abaqus 2017. Further, the result is validated with the experimental results. The experiment has been performed on the base metal, weldment-1, and weldment-2 against 7.62 AP bullet. Further, a two-dimensional explicit model has been developed for given purpose to simulate the bullet penetration at such high strain rate (103 s−1). Both bullet and plate are considered as deformable. Experimental results revealed that the depth of penetration in the base metal, weldment-1, and weldment-2 is 10.93, 13.65, and 15.20 mm respectively. Further computational results revealed that the depth of penetration of base metal, weldment-1, and weldment-2 is 10.11, 12.87, and 14.60 mm, respectively. Furthermore, weldment-1 shows more resistance against 7.62 AP bullet than weldment-2 in experimentation as well as FEA results. The percentage difference between experimental and FEA results are less than 10% which shows the prediction capability of FEA models. A feasibility analysis has been presented for using the welding consumables to weld the Armox 500T plate. Finally, in terms of ballistic resistance, the low hydrogen ferrite consumables are more appropriate than austenitic stainless-steel electrodes.

Influence of Microstructural Characteristics on Ballistic Performance and Its Mode of Failure in Shielded Metal Arc Welded Ultra-High Hard Armor Steel Joints

The welding of ultra-high hard armour (UHA) steel is highly challenging due to their higher hardness (600 HV) and higher carbon equivalent (0.80). In this investigation, 15-mm-thick UHA steel plates are welded by shielded metal arc welding (SMAW) process using three different consumables such as austenitic stainless steel (ASS), low-hydrogen ferritic steel (LHF), and duplex stainless steel (DSS). The joints were tested against a 7.62 × 54 mm Armor-piercing (AP) projectile. All three joints successfully stopped the projectile at weld metal and interface (weld/HAZ) without perforation. The ballistic performance and mechanical properties are improved than the currently used ASS electrodes, and a new method to study the mode of failure at weld metal and interface was introduced. Striations and microcracks are preferred modes of failure than wear debris in the weld metal, and soft/hard mode is preferred over soft/soft and hard/hard modes of failure at the interface.

Welding of ferritic stainless steel plate using austenitic stainless steel electrode

In this study, microstructure and phase transformation of ferritic stainless steel plate 405 using austenitic stainless steel 309-16L electrode was explained. Shielded Metal Arc Welding SMAW was used. Optical microscopy OM and scanning electron microscopy SEM were conducted to evaluate the morphology and structure of weld metal and heat-affected zone. X-ray diffraction also used to determine the crystal structure that developed during welding of bcc crystal structure and fcc crystal structure. Energy-dispersive X-ray spectroscopy EDS was used to evaluate the chemistry of the element. Microhardness was conducted in this research to determine the effect of alloying element on the mechanical properties of the joint.

Practical Investigation of FSS (AISI 430) Weldments Welded by Pulse MIG Welding Process

Ferritic stainless steels are iron-chromium alloys having chromium content usually in the range of 10.5–27%. In these steels the predominant metallurgical phase present is ferrite. These steels are Fe-Cr-C alloys with sufficient chromium or chromium plus other ferrite stabilizer, such as aluminium, niobium, molybdenum, titanium, used to inhibit the formation of austenite phase on heating. Ferritic stainless steel (FSS) is generally considered to have poor weldability when compared to austenitic stainless steel (ASS) but has recently drawn greater attention owing to their lower costs and better resistance to stress corrosion resistance than austenitic stainless steel. Ferritic stainless steels have been widely used in vessels, vehicles, household appliances, kitchen equipments and building decoration because of its excellent stress corrosion and spot corrosion resistance addition to good strength. Because it does not contain nickel, it is a cheaper alternative of austenitic stainless steel. In this work weldments of FSS welded by pulse MIG welding using argon as a shielding gas were investigated. The austenitic stainless steel (ER309L) and ferritic stainless steel (ER430) electrode wires were used to prepare the weldments. To obtain a good welded joint the welding process parameters were experimentally optimised. The microstructures and mechanical properties of the prepared weldments were investigated. In the weldment welded by austenitic stainless steel electrode wire dendritic austenitic phase was observed in the weld metal zone. In heat affected zone intragranular carbide precipitation and grain boundary martensite were observed. In case of weldments welded by ferritic stainless steel electrode wire coarse grains were formed in weld metal zone and heat affected zone. Grain boundary martensite, ferrite and intragranular carbide precipitation were found in weld metal zone and heat affected zone. Impact strength of the weldments welded by austenitic stainless steel electrode wire was found higher due to formation of austenite phase in the weld metal zone. Impact strength of the weldments welded by ferritic stainless steel electrode wire was found very low due to formation of coarse grain and martensite in the weld metal zone. The ultimate tensile strength and percentage elongation of the weldments welded by austenitic stainless steel electrode wire were found higher than the weldments welded by ferritic stainless steel electrode wire. Hence weldments of ferritic stainless steel having superior mechanical properties will be obtained by using austenitic stainless steel electrode wire. During the tensile test the specimens were broken outside the welded joint (in base metal) which confirms the good quality of the joints

The effects of heat input and polarity on wear resistance of Fe-3.5% Cr steel hardfaced using submerged arc welding

In this research, four samples of 3.5% Cr steel plates were hardfaced using austenitic stainless-steel buffer electrodes and martensitic steel hardfacing electrodes with a submerged arc welding process. This research seeks to the optimum welding parameters to get maximum wear resistance in the hardfaced layer. Heat inputs of 15 kJ cm−1 to 18 kJ cm−1 and Direct Current Electrode Positive (DC+) and Alternating Current Electrode (AC) welding polarities were applied. The microstructural analysis was conducted using an optical microscope (OM) and a scanning electron microscope (SEM). Microhardness values of the hardfaced samples were obtained using a Vickers hardness tester, and abrasive wear mass loss was measured using a dry sand rubber wheel apparatus, following ASTM G65 A standard. It was seen that the hardness profiles across the cross-section of the top hardfaced layer and along the top surface were different. The microstructure in the deposited layers, especially the quantity of martensite phase played a major influence on the wear resistance. Hardfaced layers applied with low heat input showed the highest amount of martensite phase and lowest abrasive mass loss. The hardfaced layers using AC polarity contained higher amount of martensite and lower abrasive mass loss than the layers applied using DC+ polarity.

Microstructure, Mechanical and Corrosion Behaviour of Weld Overlay Cladding of DMR 249A steel with AISI 308L

Abstract Medium strength low alloy steel is an attractive material for naval and defence applications for its excellent mechanical properties. DMR 249A is extensively used for application of ship building for its superior mechanical properties but owes poor corrosion resistance. In order to overcome the corrosion problem, Weld overlay cladding is used as an effective technique which improves the strength and corrosion resistance but also helps in manufacturing lightweight structures. Aim is to combat the corrosion by weld overlay surface coating using conventional arc welding process and observe the dilution. In the current study, Weld overlay cladding on medium strength low alloy steel (DMR 249A) of 50mm thick is done using manual metal arc welding process (MMAW) with corrosion resistant austenitic stainless steel (308L) electrode. Two layers of coating were done one over the other (each 2mm thick). Weld overlay clads were characterized for metallographic studies to observe the microstructure changes using image analyzer attached to optical microscopy and scanning electron microscopy (SEM). Mechanical testing were carried out using micro vickers hardness tester andductility bend test using Universal Testing Machine (UTM). Pitting corrosion behaviour is determined by the potentio-dynamic polarization tests in acidic chloride environment. Inter Granular Corrosion (IGC) was performed in boiling copper sulphate solution as per ASTM A-262 for 15 hours duration. The present investigation established that microstructure studies revealed increase in δ-ferrite in the weld overlay cladding. Superior mechanical properties are observed in second overlay coating compared to first overlay coating and base metal. Pitting potential in second overlay coating is observed to be more positive when compared with first overlay coating due to increase in chromium content. IGC studies showed that first overlay coating with AISI 308L observed to be more sensitized and having more weight loss which tends to be highly susceptible than second layer coating. It is attributed to the formation of high amount of delta ferrite.

Development and design of microstructure based coated electrode for ballistic performance of shielded metal arc welded armour steel joints

Joining of high strength armour steel plate developed for lighter armour vehicles using both austenitic and ferritic type of electrode/filler wire could show inferior ballistic performance of the welds. Combination of hard facing electrode and softer Austenitic Stainless Steel electrodes, though provided improved ballistic performance, might not satisfy main design criteria such as strength and toughness due to non-homogeneous microstructure of weld metal. In order to satisfy improved ballistic performance as well as other design parameters, it is highly desirable to develop coated electrode which will attribute more homogeneous microstructure in weld metal similar to high strength armour steel plate.The present investigation has attempted to obtain martensite, bainite and some amount of retained austenite in the weld metal by proper design of alloying elements in the coating of SMAW electrode based on metallurgical index. Three different electrodes attributing different combination of microstructural constituents in armour steel weld metals exhibited excellent ballistic performance combined with other design criteria such as strength and toughness at −40°C. However, among the different microstructural constituents lower bainite along with retained austenite showing maximum toughness both at room temperature and at −40°C could be considered as most desirable microstructure in armour steel weld metal.

Wear Behavior of Hardfacing Deposits on Hadfield Steel

The objective of this research was to develop the welding procedure for multilayer hardfacing of 13% Mn cast steel and study behavior of hardfacing deposits after impact applied. Austenitic stainless steel and martensitic hardfacing electrode were selected as buffer and hardfacing, respectively. Two different atmospheric conditions were compared which the first was controlling cooling rate on specimen by water during welding and another was un-controlling (by air), using shielded metal arc welding (SMAW) process. Macrostructure and microstructure were investigated by optical microscope. The hardfacing deposits were also determined by the dry sand rubber wheel machine according to procedure A of the ASTM G65 standard. The results indicated that the hardfacing layers revealed martensitic type microstructure in both controlled and uncontrolled cooling rate but their grain shapes were a little difference. For buffer layer showed austenitic type microstructure. And base metal layer presented amount of carbide in controlled cooling rate is less than in another one. The best wear resistance was obtained from controlled cooling rate condition.

Wear Behavior of Hardfacing Deposits on 3.5 % Chromium Cast Steel

The objective of this research is to develop the welding procedure for multilayer hardfacing of 3.5 %chromium cast steel and study wear behavior of hardfacing deposits. Austenitic stainless steel and martensitic hardfacing electrodes were selected as buffer and hardfacing, respectively. Four types of welding procedures were investigated, using shielded metal arc welding (SMAW) process. Three different preheatings were applied in this study. Characteristic of the macro, microstructure and worn surface deposits was investigated by optical microscope. The hardfacing deposits were also determined by the dry sand rubber wheel machine according to procedure A of the ASTM G65 standard. The results indicated that the multilayer hardfacing with and without preheating revealed no crack or defect in the Heat Affected Zone (HAZ) and other regions. The wear resistance of hardfacing presented a little difference. The best abrasive wear resistance was obtained from sample without preheating. This was due to the full martensitic microstructure of the hardfacing.

Effect of SMAW Welding Parameters on Mechanical and Structure Properties of Welded Joints of the Armoured Steel 0.32%C, 1%Cr, 1.8%Ni and 0.7% Mo

This paper introduces the effect of Shielded Metal Arc Welding (SMAW) welding parameters on the mechanical and structure properties of welded joints of the quenched and tempered armoured steel 0.32%C, 1%Cr, 1.8%Ni and 0.7% Mo. In this study, three welding consumables – low-carbon & low-alloy which are both Low Hydrogen Ferritic (LHF) electrodes, and austenitic stainless steel (ASS) electrode - and three heat inputs were used. Furthermore, the effect of preheating of the armoured plates on the mechanical properties of both the welded joint and the heat affected zone was investigated. The use of the lowhydrogen ferritic electrodes provided superior tensile properties while the austenitic electrodes exhibited pronounced toughness. Higher heat input and/or preheating should be performed when using LHF electrodes, however, caution should be given when using lowalloy steel electrodes due to their sensitivity to the applied cooling rate. On the contrary, preheating is less important when using ASS electrodes due to their high resistance to cold cracking. Higher heat input and preheating temperatures increase the softening of the hardened region, adjacent to the fusion zone, which decrease the possibility of Hydrogen induced cracking (HIC).

Addition of cerium oxide in the flux formulations of a basic-coated stainless steel electrode

Basic-coated electrodes are preferred for welding medium and thick section austenitic stainless steels because these consumables provide weld metal with high toughness, quality and resistance to cracking. Strength and toughness of weld metals depend on their microstructure, which is determined by the concentration of various alloying elements, impurities as well as the welding thermal cycle. However, in basic-coated electrodes, optimisation of flux formulation is complex because slag detachability is a problem with basic fluxes that confer high weld metal toughness. This study investigates the effects of systematically varying the cerium oxide content in the flux coating used in a basic-coated austenitic stainless steel electrode for shielded metal arc welding (SMAW). SMAW process with 16-mm-thick stainless steel plates and in-house-developed electrodes of 3.15 mm in size added with different levels of cerium oxides in the flux coating was used to prepare the weld pads. The weld pads were qualified with radiography examination as per ASME section III class I components. Tensile specimens were prepared as per American Society for Testing and Materials (ASTM) E8 and tensile properties were evaluated at both ambient and service temperatures. Charpy ‘U’ notch impact specimens were prepared in the as-welded and fully sensitized conditions (1,023 K/100 h) and the impact tests were carried out as per ASTM E23. Variation in the weld metal chemistry, mechanical properties, oxygen content, inclusion morphology and microstructure with cerium oxide content in the flux was examined. The results indicated that at an optimal level of cerium oxide addition in the flux coating played a major role in reducing sulphur and oxygen content; subsequently, it improved the mechanical properties of the weld metal. In this paper, the results of detailed studies and analysis were discussed on microstructures using optical and scanning electron microscope carried out on the weld metals produced with different levels of cerium oxide in the flux.

Stabilizing the ferroelectric phase of KNO3 thin films using substrate electrodes

In this study, polarization–voltage (P–V) and current density–voltage (J–V) measurements were utilized to investigate the effect of nickel (Ni), 304 austenitic stainless steel (SS) and tantalum (Ta) substrate electrodes on the ferroelectric phase stability of KNO3 thin films. P–V loops and J–V switching peaks were obtained to suggest the intriguing possibility of attaining ferroelectric phase stability in KNO3 films by means of an appropriate substrate electrode. SS substrate electrode stabilized the ferroelectric phase to room temperature (28°C) while Ni substrate electrodes stabilized the phase close to room temperature. On the other hand, Ta substrate electrodes severely degraded the ferroelectric phase of the deposited films. A strong agreement was found between the appearance of the P–V hysteresis loop and the occurrence of the J–V switching peaks confirming polarization switching to be responsible for the observed ferroelectric properties exhibited by the thin film samples.

Effect of ferro-titanium deoxidant on metal recovery and slag detachability of an austenitic stainless steel electrode

Basic coated E308-15 austenitic stainless steel electrodes with 2.5 to 6% ferro-titanium (Fe-Ti) as deoxidant were extruded, with the major elements Cr, Ni, Mn and Si being held constant. Experimental studies were conducted on the role of Fe-Ti deoxidant on metal recovery and slag detachability of this electrodes. The amount of Fe-Ti required to optimise the metal recovery and slag detachability was studied. Electrodes with more than 4% Fe-Ti deoxidant showed better arc characteristics, metal recovery and slag detachability. Adequate delta ferrite content with ferritic-austenitic mode of solidification was obtained in electrodes with 4 and 6% Fe-Ti deoxidant.

Fatigue Crack Growth Behavior of AISI 409M Grade Ferritic Stainless Steel Welded Joints Using Austenitic, Ferritic and Duplex Stainless Steel Electrodes

This paper reveals the fatigue crack growth behaviour of the shielded metal arc welded AISI 409M grade ferritic stainless steel joints fabricated using austenitic stainless steel (ASS), ferritic stainless steel (FSS) and duplex stainless steel (DSS) electrodes. Centre cracked tensile (CCT) specimens were prepared to evaluate fatigue crack growth behaviour. Servo hydraulic controlled fatigue testing machine with a capacity of 100 kN was used to evaluate the fatigue crack growth behaviour of the welded joints. It is found that the joints fabricated by DSS electrode showed superior fatigue crack growth resistance compared to the joints fabricated by ASS and FSS electrodes. Higher yield strength and relatively higher toughness of the weld metal may be the reasons for superior fatigue performance of the joints fabricated by DSS electrode.