Stainless Steel Research Articles

An HTS CORC Conductor With a Stainless Steel Sheath: Numerical Simulation and Electromagnetic Properties

An HTS CORC Conductor With a Stainless Steel Sheath: Numerical Simulation and Electromagnetic Properties

Fabrication of Mo-encapsulated stainless steel by powder metallurgy and assessment of localized corrosion resistance

Fabrication of Mo-encapsulated stainless steel by powder metallurgy and assessment of localized corrosion resistance

Double-pulse laser peening as a surface enhancement technology

In this paper, we discuss double-pulse laser peening (DPLP) as surface enhancement technology. Although single-pulse laser peening (SPLP) has yielded excellent results across various applications, its processing performance and efficiency are limited. The DPLP technique involves two laser pulses with a controlled irradiation interval and intensity, enhancing laser absorption through the plasma plume and generating high-amplitude laser-induced shock waves. This study involved conducting DPLP experiments on stainless steel, comparing the outcomes with those of conventional SPLP to assess DPLP’s functionality. After the initial prepulse irradiation, the subsequent main pulse was timed and irradiated onto the stainless steel. We evaluated the surface hardness to ascertain the impact of laser peening. The findings indicated that the surface hardness achieved with DPLP was up to 64% greater than that with SPLP. Additionally, the surface hardness achieved through DPLP depended on the delay time between the pulses and the intensity of the initial prepulse. These findings suggest that DPLP can significantly enhance surface hardness, providing a potential pathway for improving material performance in various industrial applications. Furthermore, simulation experiments of DPLP were performed using a one-dimensional simulation code that calculates the laser-matter interaction during the peening process. The pressure profiles generated by the simulation closely matched the experimentally derived hardness profiles, confirming the simulation’s ability to predict the mechanical effects induced by DPLP on the target sample and assist in further optimization of the DPLP process.

Efficacy of Disinfectants for Monkeypox Virus Inactivation on High Touch Surface Materials in Low-Resource Settings.

Disinfection efficacy tests were conducted on surface carriers inoculated with the monkeypox virus (MPXV) by applying six disinfectant solutions (and three controls) on six surfaces common in low-resource settings: four nonporous surfaces (stainless steel, glass, plastic, and latex) and two porous surfaces (ceramic and wood). Disinfectants were wiped on carriers in triplicate, with a 1 min contact time: 0.05 and 0.5% sodium hypochlorite, 70% ethanol, two quaternary ammonium compound (QAC)-based disinfectants, and 1.4% hydrogen peroxide. MPXV was then quantified, and log10 removal values were calculated. Sodium hypochlorite (0.05 and 0.5%) and ethanol (70%) removed MPXV to below detection level, ≥ 99.97% reduction for nonporous surfaces, and ≥99.40% for wood, QAC-based disinfectants were efficacious on nonporous surfaces (≥99.97% inactivation) but had diminished efficacy on wood, a porous surface, and 1.4% H2O2 had limited efficacy across all tested surfaces. Results varied by disinfectant type and surface type. Based on our results, we recommend using 0.05% sodium hypochlorite or 70% ethanol with 1 min contact time to inactive MPXV on clean nonporous and porous surfaces. As MPXV is evolving, future research with additional disinfectants, application methods, and environmental conditions and research to understand adsorption, disinfection efficacy, and transmission risk on porous surfaces are needed to develop practical disinfection recommendations.

MAIN STAGES OF DESIGNING RESOURCE-SAVING TECHNOLOGIES FOR INGOT DEFORMATION ON HYDRAULIC PRESSES

Objective. To study the technological process of forging large ingots on hydraulic presses in order to identify and reduce resource consumption. Research methods. A finite element method that makes it possible to assess the stress-strain state of a workpiece, the possibility of levelling it, and homogenising it by controlling the factors that form the optimal forging method for a given workpiece. Results. A resource-saving technological process based on the optimal forging method has been developed, which allows to bring the quality of the designed products to a new level and leads to an increase in technical and economic indicators of production. By controlling the stress-strain state of the metal, high quality forged products can be achieved and resource-saving technologies for forging forgings of high-alloy steel grades and alloys can be created. Scientific novelty. The factors that form the rational resource-saving technological process of plastic deformation and the method of forging large forgings from alloyed, stainless steels and alloys on hydraulic presses, as well as the directions of their optimisation, have been formed. The finite element method allows us to predict the distribution fields of the workpiece’s stress-strain parameters, metal microstructure, and grain size. Practical value. Practically grounded recommendations for optimal modes of forging ingots from tool steel grades were developed. This will reduce energy consumption, save time in the production of forged products and generally intensify the process of plastic deformation. The proposed recommendations can be applied not only in the processes of forging tool steel grades but also in other types of hot plastic deformation of metals of a wide range.

Static and Thermal Analysis of Internal Combustion Engine Valves

Abstract: In this paper the 3D model of the internal combustion engine valves was realized using Autodesk Inventor Professional 2024 and finite element analysis, static and thermal was performed, in order to determine the state of stress, deformation and temperature evolution, by applying restrictions and loads conditions. Two materials were chosen, for internal combustion engine valves, in accordance with the specialized literature. The materials taken for static and thermal analysis was Stainless Steel AISI 446 and NiCr0TiAl. Following the comparative study for the two models, it can be specified the importance of the material for the construction of the internal combustion engine valves who depends on the material properties and their design.

Corrosion Properties of Weld Metal in 304 Stainless Steel for Food Grade Using GTAW with Various Types of Backing Gas

Corrosion Properties of Weld Metal in 304 Stainless Steel for Food Grade Using GTAW with Various Types of Backing Gas

High‐Temperature Oxidation Response of 444 Ferritic Stainless Steel in a Synthetic Automotive Exhaust Gas

The high‐temperature oxidation behavior of 444 ferritic stainless steel has been studied in cyclic oxidation experiments using synthetic automotive exhaust gas atmospheres at 950 and 1050 °C. The weight gain per unit area of the 444 ferritic stainless steel following oxidation at 950 °C for 100 h iss 85.7% lower than recorded at 1050 °C. The oxide scale at both temperatures consisted of Fe–Cr and Mn–Cr spinels in the outer layer and Cr2O3 in the inner layer. Nodule formation and spallation of the oxide scale are identified as the main causes of breakaway oxidation. The depth of the internal oxides gradually increases with the oxidation time. The nucleation and growth of internal SiO2 result in the formation of metal protrusions, which are eventually consumed in the formation of a SiO2 layer. The SiO2 layer is formed at the interface between the oxide scale and the substrate at 1050 °C. The nucleation and growth of internal SiO2, in combination with lateral growth of SiO2 at the Cr2O3 layer/substrate interface contributed to the formation of the SiO2 layer.

Polymer Tools Produced by Fused Filament Fabrication for Steel-Bending Process: Effect of Layering Orientation

Rapid tooling with polymer tools produced via additive manufacturing offers significant benefits in sheet metal forming processes as it allows for the production of parts with high accuracy while reducing tool production costs. In this research, the authors evaluate the performance of polymer punches and dies in the sheet metal bending of 2 mm thick AISI 314 stainless steel. The tools were made using nylon filled with carbon fiber and produced through Fused Filament Fabrication. Two different print orientations—horizontal and vertical—were compared. This experimental study focused on the accuracy of the sheet’s bending angle and thickness while also measuring the deformation induced in the tools. A new methodology was proposed combining both tools and sheet measures to highlight not only the sheet’s accuracy but also the behavior of the polymer tools. The results demonstrate that despite the permanent deformation of the tools, they were able to produce sheets with a geometry accuracy of less than 0.5%

The Role of Al/Ti in Precipitate-Strengthened and Austenite-Toughened Co-Free Maraging Stainless Steel

The strength of ultra-low carbon maraging stainless steels can be significantly enhanced by precipitating nanoscale intermetallic secondary phases. Retained or reversed austenite in the steel can improve its toughness, which is key to achieving an ideal combination of strength and toughness. Ti and Al are often used as cost-effective strengthening elements in maraging stainless steels but the synergistic toughening and strengthening mechanisms of Ti and Al have not been studied. To investigate the synergistic toughening and strengthening mechanisms of Ti and Al in Co-free maraging stainless steels, this paper focuses on the microstructure and mechanical properties of three alloys: Fe-12Cr-11Ni-1.7Al-0.5Ti (Steel A), Fe-12Cr-11Ni-0.5Ti (Steel B), and Fe-12Cr-11Ni-1.7Al (Steel C). The impact of Ti and Al on the microstructure and mechanical properties was investigated using X-ray diffraction (XRD), high-resolution transmission electron microscopy (TEM), and thermodynamic simulations. The relationship between microstructure, strength, and toughness is also discussed. The results indicated that Steel A, containing both Al and Ti, exhibited the highest strength level after solution treatment at 900 °C, with an ultimate tensile strength reaching 1571 MPa after aging at 540 °C. This is attributed to the simultaneous precipitation of spherical β-NiAl and rod-shaped η-Ni3Ti phases. Steel B, with only Ti, formed a significant amount of Ni-rich reversed austenite during aging, reducing its ultimate tensile strength to 1096 MPa. Steel C, with only Al, showed a high strength–toughness combination, which was achieved by forming dispersive nano-sized intermetallic precipitates of β-NiAl in the martensitic matrix with a slight amount of austenite. It is highlighted that Al has superior toughening and strengthening effects compared to Ti in the alloy system.

Effect of the Reactor Material on the Reforming of Primary Syngas

Syngas, mostly hydrogen and carbon monoxide, has traditionally been produced from coal and natural gas, with biomass gasification later emerging as a renewable process. It is widely used in fuel synthesis through the Fischer–Tropsch (FT) process, where the H2/CO ratio is crucial in determining product efficiency and quality. In this sense, this study aimed to reform an emulated syngas resulting from the supercritical water gasification of biomass, tailoring it to meet the H2/CO ratio required for FT synthesis. Conditions resembling dry reforming were applied, using temperatures from 600 to 950 °C and steel wool as a catalyst. Additionally, the effects of Inconel and stainless steel as reactor materials on syngas reforming were investigated. When Inconel was used, H2/CO ratios ranged between 1.04 and 1.84 with steel wool and 1.28 and 1.67 without. When comparing reactions without steel wool performed either in the Inconel or the stainless steel reactors, those using Inconel consistently outperformed the stainless steel ones, achieving CH4 and CO2 conversions up to 95% and 76%, respectively, versus 0% and 39% with stainless steel. It was concluded that the Inconel reactor exhibited catalytic properties due to its high nickel content and specific oxides.

Experimental study on the heat input behavior of wire-arc additively manufactured 316L stainless steel parts for repairing applications

Wire arc additive manufacturing (WAAM) as an emerging manufacturing technique for fabricating large size metallic components with a higher deposition rate and lower material wastage. In this research, a thin walled-part was fabricated from stainless steel 316L with various heat input (HI) (low heat deposited wall (LHDW) and high heat deposited wall (HHDW) using the cold metal transfer (CMT)-based WAAM process. The microstructure characteristics, metallurgical characterization, and mechanical properties of the WAAM manufactured thin-walled component were examined. The deposited wall measuring 120 mm in length and 50 mm in height was fabricated by WAAM using ER316L wire and CMT. Microstructure of the deposit parts consists of the equiaxed, coarse, and columnar grains with epitaxial growth of dendrites were formed. The decrease in HI leads to the improvement of material hardness, yield and ultimate tensile strength (UTS) as well as the percentage elongation after fracture of the material decreases. EBSD analysis demonstrates the average grain size of 0.98 µm in LHDW and 2.43 in HHDW respectively. XRD results shows that main crystal structure found in WAAM thin-walled sample was γ-austenite phases. The microhardness distribution of the fabricated component exhibited the stability characteristics with the average value ranging between 213–237 HV. The tensile studies demonstrate the UTS of the LHDW and HHDW along the horizontal direction are 477 MPa greater than the vertical direction of 468 MPa and observed the anisotropy properties. The fractured surface was characterized by the emergence of obvious dimples revealing the ductile fracture. The lower HI and finer solidification structure of component fabricated by LHDW has greater tensile and hardness properties than that of HHDW. This study presents the initial assessment results for repairing stainless steel components subjected to mechanical damage.

Experimental comparison of closed cooling systems of photovoltaic modules

Relevance. The need to increase the efficiency of solar modules to 15–20% by cooling their surface, which in spring and summer is able to heat up to 70 ℃. Heat collection from photovoltaic modules is an additional opportunity to accumulate heat and use it for their own needs, especially for isolated power systems. The article discusses methods of closed cooling using tubes made of copper, metal plastic and stainless steel. All measurements were carried out in summer at a real, operating solar power plant located in the Crimea village of Karyernoe. Aim. To experimentally determine and identify the effect of the most efficient cooling system for photovoltaic modules. Methods. Methods of empirical research. In the experiment, sensors connected to the Arduino UNO system were used to measure the temperature and humidity of the ambient air, the temperature of the refrigerant at the inlet and outlet, and the data were recorded in an Excel table. Soudal FIX ALL adhesive sealant is used to fix the cooling system. Results and conclusions. The authors have obtained volt-ampere characteristics, refrigerant inlet and outlet temperatures, photovoltaic modules surface temperatures. The cooling system made of stainless steel pipes showed the greatest cooling efficiency of the solar module, which allowed reducing the module temperature from 66 to 38℃ at some points. This increased the efficiency of photoelectric module by 3.5% relative to the rated power. The heated liquid from the photoelectric module has cooled down to its original temperature values, thanks to the installed cooling radiator, for the possibility of reuse of the liquid in the solar panel cooling circuit.

A Short Review on the Wire-Based Directed Energy Deposition of Metals: Mechanical and Microstructural Properties and Quality Enhancement

Wire-based directed energy deposition (WDED) is an emerging additive manufacturing process garnering significant attention due to its potential for fabricating metal components with tailored mechanical and microstructural properties. This study reviews the WDED process, focusing on fabrication techniques, mechanical behaviors, microstructural characteristics, and quality enhancement methods. Utilizing data from the Web of Science, the study identifies leading countries in WDED research and highlights a growing interest in the field, particularly in materials engineering. Stainless steel, titanium, aluminum, and copper-based alloys are prominent materials for WDED applications. Furthermore, the study explores post-processing techniques such as machining, heat treatment, and surface finishing as integral steps for quality enhancement in WDED components.

Effects of Cold Gas Tungsten Arc Welding on Dissimilar DHP-CW024A Copper/304 SS Thin Lap Joint

Copper and stainless steel possess distinct properties that make them suitable for different applications (i.e. e-mobility, nuclear power plants, etc.). However, the high thermal conductivity of copper presents a significant challenge in welding. In fact, researchers have explored various fusion welding processes for joining copper to steel and concluded that fusion welding is generally difficult or even unsuitable for obtaining sound and defects free joints. The present study investigated the feasibility of dissimilar lap joint between copper and stainless-steel thin plates using Cold Gas Tungsten Arc Welding (CGTAW) without a filler material and with no significant geometrical distortion of welded plates. The weld was created by consecutive partially overlapped spots, whose welding time varied between 100 and 150 ms, in upgraded conventional TIG machine equipped with cold TIG welding function. Samples made with 150 ms welding time showed a near-uniform distribution of equiaxed copper grain microstructure, while those obtained with 100 ms exhibited significant differences in grain size with the presence of steel inclusions in globule and vortex shapes. The joints demonstrated exceptional flexibility, allowing it to be bent up to a 180º angle without any visible damage. The maximum tensile strength of sample obtained with a welding time of 150 ms was 220 MPa with a fracture located in the heat-affected zone. The sample welded with a welding time of 100 ms exhibited 171 MPa of tensile strength with the fracture along the melting spot area due to pronounce mixing of welded materials. All the samples showed ductile behavior in the fracture zone. Eventually, the application of CGTAW resulted in promising at obtaining joint with good mechanical properties.

SYNTHESIS OF HYDROPHOBIC COATINGS ON STAINLESS-STEEL MESH AND ITS PERFORMANCE

Hydrophobic coatings were fabricated on 400-mesh 304 stainless steel by combining hydrothermal treatment and chemical modification. The hydrophobicity of the surfactant coatings was evaluated. The fabricated coatings were characterized by scanning electron microscopy, contact angle measurements and X-ray diffraction. The results revealed that a hydrophobic coating with a water contact angle of [Formula: see text] could be successfully synthesized under specific conditions: a concentration of 0.005[Formula: see text]mol⋅L[Formula: see text] C[Formula: see text]H[Formula: see text]SO4Na and subsequent modification with a 1[Formula: see text]mol⋅L[Formula: see text] ethanol stearate solution for 24[Formula: see text]h. This outcome highlights the potential of this methodology for producing highly efficient hydrophobic coatings for stainless steel mesh substrates.

Cranioplasty Approaches for Cranial Defects: A Case Series

Abstract Cranial defects are commonly caused due to road traffic accidents, tumor, postneurosurgery, or congenital deformities. Protection of the cranial structures, maintaining cerebrospinal fluid dynamics, and esthetics are some of the prime considerations while restoration of such defects. The use of autograft or allograft materials such as bone from a self or another donor site from ribs, ilium, tibia, scapula, and fascia and procedures such as split-thickness cranioplasty were carried out in the past. However, in larger defects, alloplastic materials such as celluloids, methyl methacrylate, hydroxyapatite, polyethylene, silicone, and metals such as titanium, aluminum, and stainless steel, were used for restoration. Irrespective of the material of choice, it is desirable of the prosthetic material to demonstrate low thermal conductivity, optimal strength, low infection rate, longevity, close adaptation to the defect, and fixability with plates to adjacent bone. Before digital imaging, conventional impressions were made, and approximations were done to fabricate cranial plates. With the advent of digital technology and bone imaging techniques with alongside the development of printed and milled materials, accurate cranial prosthesis can be fabricated. We cannot disregard conventional techniques as these are still used in places where access to digital technology is limited and also for patients who cannot afford the cost incurred with digital technology. The case series presents one case, which was fabricated with a conventional method, and two cases with two different approaches using digital technology. The paper aims to present various advantages, limitations, and nuances needed while the fabrication of such a prosthesis with these three methods.

Effect of induction heat treatment on microstructure, mechanical and corrosion properties of stainless steel 308 L fabricated using wire arc additive manufacturing

Induction solution heat treatment can change the mechanical characteristics and corrosion resistance properties of 308 L manufactured via wire arc additive manufacturing (WAAM). Moreover, compare with traditional heat treatment methods, this method can reduce heat treatment time and achieve in-situ local heat treatment. In this paper, in-situ induction heat treatment at 1100 °C for 2, 4, and 6 min were applied on 308 L thin-walled parts produced by WAAM. The result show that ferrite and austenite phase proportions were changed after induction solution heat treatment. Heat treatment at 1100 °C effectively reduced the δ-Fe and σ-Fe content, resulting in a slight decrease in UTS and microhardness, while YS and EL have a certain degree of increase. σ-Fe exhibits a more pronounced strengthening effect than austenite, albeit at the potential expense of steel’s elasticity. At the same time, induction heat treatment alters the ferrite to austenite ratio, which also enhances the anti-corrosion properties of the stainless steel. However, the presence of σ-Fe will cause a worsening of the corrosion resistance of the steel. In addition, as the heat treatment progresses, the ferrite’s microstructure in the deposition direction undergoes a significant transformation, changing from continuous dendrites to a few equiaxed grains.

Effect of preheating substrates and process parameters on cladding track geometry fabricated by laser cladding

Laser cladding (LC) is an advanced technique used for repairing large-scale components, such as rotors and valves, in thermal power plants and steel rolling mills. This technology is designed to facilitate efficient repairs, minimize repair costs, conserve materials, reduce processing time, and ensure adequate dilution between the substrate material and the deposited coating, while also enhancing corrosion resistance. In this research, the effects of preheating substrates and input process parameters on the geometric accuracy of single-track deposits, as well as the microstructure composition of multi-track deposits, were investigated. The Taguchi method was used to design an L9 orthogonal experimental array. The impact of process parameters, including substrate temperature, laser power, and scanning speed, on the morphology of a single track (track width, height, penetration depth, and dilution) was evaluated through ANOVA statistical analysis. SS316L stainless steel, recognized for its wear resistance, was used as the deposition material. The findings reveal that substrate temperature is the most critical factor influencing the dilution of the coating. Additionally, the microstructure of the deposited layers were systematically analyzed.

Anisotropic Specular Image‐Based Lighting Based on BRDF Major Axis Sampling

AbstractAnisotropic specular appearances are ubiquitous in the environment: brushed stainless steel pans, kettles, elevator walls, fur, or scratched plastics. Real‐time rendering of these materials with image‐based lighting is challenging due to the complex shape of the bidirectional reflectance distribution function (BRDF). We propose an anisotropic specular image‐based lighting method that can serve as a drop‐in replacement for the standard bent normal technique [Rev11]. Our method yields more realistic results with a 50% increase in computation time of the previous technique, using the same high dynamic range (HDR) preintegrated environment image. We use several environment samples positioned along the major axis of the specular microfacet BRDF. We derive an analytic formula to determine the two closest and two farthest points from the reflected direction on an approximation of the BRDF confidence region boundary. The two farthest points define the BRDF major axis, while the two closest points are used to approximate the BRDF width. The environment level of detail is derived from the BRDF width and the distance between the samples. We extensively compare our method with the bent normal technique and the ground truth using the GGX specular BRDF.