Magnetic Stainless Steel Research Articles

Compressive Properties of Additively Manufactured Metal-Reinforced PLA and ABS Composites.

The development of multi-material filaments has enabled fused filament fabrication-based additive manufacturing to address demand for high-performance lightweight multifunctional components. In this study, polylactic acid (PLA) and acrylonitrile butadiene styrene based filaments with metallic reinforcements of magnetic iron (MI), stainless steel (SS), bronze (Br), copper (Cu), Bismuth (Bi), and Tungsten (W) were investigated to elucidate their complex processing-structure-property relationships. The microstructure of 3D-printed materials were characterized by microscopy and analyzed to determine the metal cross-sectional area percentage and the relationship between metal reinforcement, the polymer matrix, and porosity. Compression testing was conducted in directions parallel and perpendicular to the build direction in order to evaluate the effect of orientation and metal reinforcement on the mechanical properties. 3D-printed specimens experienced either fracture through print layers or layer-wise interfacial rupture for loads applied perpendicular and parallel to the print layers, respectively. A dependence of yield strength on loading orientation was observed for Br-PLA, Cu-PLA, SS-PLA, Bi-ABS, and W-ABS; however, MI-PLA and pure ABS specimens did not exhibit this sensitivity. Metal reinforcement also influenced the magnitude of compressive yield strength, with MI-PLA and SS-PLA demonstrating increased strength over Br-PLA and Cu-PLA, while ABS demonstrated increased strength over Bi-ABS and W-ABS. These results demonstrate the importance of considering orientation in printing and applications, the trade-off between various metallic reinforcements for added multifunctionality, and the potential of these tailored polymer composites for novel 3D-printed structures.

ВПЛИВ ЕЛЕКТРОФІЗИЧНИХ ПАРАМЕТРІВ МАТЕРІАЛІВ НА ЕЛЕКТРИЧНІ ВТРАТИ В МЕТАЛЕВИХ КАРКАСАХ ІНДУКЦІЙНИХ КАНАЛЬНИХ ПЕЧЕЙ

On the basis of mathematical modelling of electromagnetic processes, electrical losses in the metal frames of the two-inductor induction channel furnace in a wide range of specific electrical conductivity of the non-magnetic material of the frames were determined. Research was conducted for two options for sectioning the lower frame of the furnace (vertical and horizontal) and two values of the phase angle between the voltages on the inductors (0 and 180 electrical degrees). For these cases, losses in furnace frames made of ferromagnetic material (construction carbon steel and magnetic stainless steel) were also calculated. Recommendations are presented on the selection of the frame material, the sectioning option and the phase angle between the voltages, which ensure minimal electrical losses. Ref. 13, fig. 4. Key words: induction channel furnace, metal frames, mathematical modelling, electrical losses.

Realization of Soft Magnetic Properties in Precipitation Hardening Stainless Steel

Precipitation hardening of soft magnetic stainless steel was investigated to achieve both workability (low hardness during machining) and durability (high hardness in practical use) while maintaining soft magnetic properties. NiAl intermetallic compound was used for precipitation hardening. The relationship among aging temperature, microstructure, magnetic properties, and hardness was investigated for 22 composition samples with the basic composition of 15Cr-1Si-2Mo-3Ni-1Al-0.15Ti-bal. Fe (in wt.%) and varying compositions of Si, Mo, Ni, Al, and Cu. The maximum aged hardness was obtained by solution treatment at 1030 °C followed by aging at 550 °C. Soft magnetic properties were achieved with a single-phase ferrite composition (δ: bcc structure), and the hardness level could be adjusted with the concentration of solid solution strengthening elements. Two indexes of the relationship between microstructure and magnetic properties and between solid solution strengthening elements and hardness were obtained. The soft magnetic properties obtained by solution treatment were maintained after aging despite the occurrence of nonmagnetic precipitates of NiAl intermetallic compound. This is because precipitates do not become pinning sites for the domain wall due to their small size and distance between precipitates (1/175 and 1/26 of the domain wall, respectively). As a result, a practical precipitation hardening soft magnetic stainless steel with good properties of 227 HV after solution treatment, 372 HV and a coercive force of 64 A/m after aging treatment was realized.

Dynamic recrystallization behavior and mechanism of Fe–Cr–Ni–Mn–Mo–N low magnetic stainless steel during hot deformation

Dynamic recrystallization behavior and mechanism of Fe–Cr–Ni–Mn–Mo–N low magnetic stainless steel during hot deformation

Fabrication of robust superhydrophobic magnetic multifunctional coatings and liquid marbles

To obtain durable and multi-function superhydrophobic surfaces, we reported a facial method to prepare a multifunctional suspension (γ-Fe2O3@SiO2@PDMS suspension) named as FSP suspension, in which γ-Fe2O3 was coated by the silica shell and PDMS was used as the outer layer. Superhydrophobic magnetic polyurethane (SMPU) sponge was prepared by immersing the polyurethane (PU) sponge into the FSP suspension, exhibiting the superior ability to absorb oil. In addition, it could also move directionally by the attraction of magnets and absorb the oil along the fixed path. The heated superhydrophobic magnetic stainless steel (H-SMSS) mesh was acquired by spraying FSP suspension onto the stainless steel mesh and then heating at 400°C, which demonstrated superior superhydrophobicity and resistance to abrasion and chemical corrosion. Besides, the H-SMSS mesh displayed excellent flux and efficiency to separate the oil/water mixture. Rolling droplets on FSP particles, the superhydrophobic magnetic liquid marbles (SMLMs) were fabricated, in which liquids with different volumes were encapsulated and transported directionally. Further, it was convenient to inject liquid into the SMLM and withdraw liquid from it. Thus, the prepared FSP suspension has promising applications in constructing large-area, robust, and multifunctional surfaces and microreactors.

Microstructure and properties of Nb, V and N alloyed low magnetic hot rolled stainless steel plate

Microstructure and properties of Nb, V and N alloyed low magnetic hot rolled stainless steel plate

Temperature Performance of Stainless Steel AISI420B Orthopedic Drill Bits Simulation Study

In orthopedic and trauma surgery, the drilling of bone is the process of preparing, making, and enlarging a hole of circular crosswire in a solid anisotropic material bone structure. The failure of irreversible osteonecrosis occurs when the temperature rises to 47 °C or higher during bone drilling. Osteonecrosis is a disorder that leads to the death of bone tissue cells, resulting in weaker contact between implants and bone, and in some cases, the loss of strong and stable attachment to the bone. Previous studies had concentrated on drill bit material, design, point angle, force, speed, and feed rate. This study outlines the technique for developing a drilling-related finite element model to verify the drilling process’s efficacy using a computer simulation approach. Software LS-DYNA © 2011-2020 LST was used to conduct a drilling model based on the finite element (FE) technique. The temperature behavior of orthopedic chromium type martensitic magnetic stainless steel AISI420B twist drill bit (Ø 4.3 mm) was determined. The findings were quantified, and the outcomes of the simulated and actual evaluations were compared. The surgeon’s typical drilling technique or pattern was used in this study, with a penetration angle of no more than 30°, and performed using a battery-powered surgical hand drill. A forward-looking infrared (FLIR) camera for temperature detection was used to record drill bits thermal data throughout the experiment. The utilization of two factorial analyses in the design of experiment (DOE) and analysis of variance (ANOVA) revealed that the simulation result had higher mean performance confirmation than the actual experimental result, with a difference of 10.9102%. The AISI420B showed good heat conductivity, and minor wear than typical stainless steel drill bits in the market for bone drilling. Therefore, the AISI420B stainless steel twist drill bit tested able to perform well for bone drilling.

Additive Manufacturing and Characterization of Metal Particulate Reinforced Polylactic Acid (PLA) Polymer Composites.

Affordable commercial desktop 3-D printers and filaments have introduced additive manufacturing to all disciplines of science and engineering. With rapid innovations in 3-D printing technology and new filament materials, material vendors are offering specialty multifunctional metal-reinforced polymers with unique properties. Studies are necessary to understand the effects of filament composition, metal reinforcements, and print parameters on microstructure and mechanical behavior. In this study, densities, metal vol%, metal cross-sectional area %, and microstructure of various metal-reinforced Polylactic Acid (PLA) filaments were characterized by multiple methods. Comparisons are made between polymer microstructures before and after printing, and the effect of printing on the metal-polymer interface adhesion has been demonstrated. Tensile response and fracture toughness as a function of metal vol% and print height was determined. Tensile and fracture toughness tests show that PLA filaments containing approximately 36 vol% of bronze or copper particles significantly reduce mechanical properties. The mechanical response of PLA with 12 and 18 vol% of magnetic iron and stainless steel particles, respectively, is similar to that of pure PLA with a slight decrease in ultimate tensile strength and fracture toughness. These results show the potential for tailoring the concentration of metal reinforcements to provide multi-functionality without sacrificing mechanical properties.

The Effect of Aging on Precipitates, Mechanical and Magnetic Properties of Fe-21Cr-15Ni-6Mn-Nb Low Magnetic Stainless Steel

The effect of aging on the precipitates, mechanical and magnetic properties of Fe-21Cr-15Ni-6Mn-Nb low magnetic stainless steel were investigated. The steel was aged at 550–750 °C for 2 h after solution heat treatment at 1100 °C for 1 h. During the aging treatment, the (Nb, V)(C, N) particles gradually precipitated in the grain, which were coherent or semi-coherent with the matrix. When the aging temperature was beyond 650 °C, the coarsening rate of (Nb, V)(C, N) particles increase rapidly and the coherent orientation between (Nb, V)(C, N) particles and the matrix was lost gradually. Meanwhile, coarse M23C6 was distributed at the grain boundary with chain shape, which was non-coherent with the matrix. The coarsening behavior of (Nb, V)(C, N) precipitates in the grain was analyzed, and the size of the particles precipitated after aging treatment at 650°C for different time was calculated and studied. After aging treatment at 650 °C for 2 h, the yield strength and tensile strength of the stainless steel was 705.6 MPa and 1002.3 MPa, the elongation and the relative magnetic permeability was 37.8% and 1.0035, respectively.

Compositionally graded magnetic-nonmagnetic bimetallic structure using laser engineered net shaping

Fabrication of compositionally-graded magnetic-nonmagnetic bimetallic structures was successfully completed using a laser engineered net shaping (LENS™) system. A graded magnetic functionality was implemented by directly transitioning from non-magnetic austenitic stainless steel 316 (SS316) to magnetic ferritic stainless steel 430 (SS430) in a single structure. LENS™ additive manufacturing utilizes a high-powered laser to continuously melt and bond metallic powder in successive layers to create the 3D structure. Microstructures revealed a preferred grain growth direction at the interfaces of the deposited layers. Micro-hardness values across the part’s cross-section exhibited a smooth transition from the highest value of 266 ± 4 HV in the SS430 region to the lowest value at the SS316 substrate of 174 ± 3 HV. Magnetic functionality was observed on the SS430 side of the bimetallic structure, showing how LENS™ can additively combine materials of varying compositions for location-specific functionality.

Magnetic Separation Using HTS Bulk Magnet for Cs-Bearing Fe precipitates

A peculiar magnetic separation technique has been examined in order to remove the Cs-bearing Fe precipitates formed of the waste ash from the withdrawn incinerator furnaces in Fukushima. The separation system was constructed in combination with high temperature superconducting bulk magnets which generates the intensive magnetic field over 2 T, which was activated by the pulsed field magnetization process. The separation experiment has been operated with use of the newly-built alternating channel type magnetic separating device, which followed the high-gradient magnetic separation technique. The magnetic stainless steel filters installed in the water channels are magnetized by the applied magnetic fields, and are capable of attracting the precipitates bearing the Fe compound and thin Cs contamination. The experimental results clearly exhibited the positive feasibility of HTS bulk magnets.

Application of high gradient magnetic separation for oil remediation using polymer-coated magnetic nanoparticles

Abstract Oil can be released into the environment from different sources such as runoff, accidental oil spills and oily wastewater discharges produced during industrial activities and can have dramatic impacts on the environment. The limitations of current clean-up techniques have inspired researchers to study the application of nanotechnology for oil remediation. Previously, we reported excellent oil-removal efficiency of a reference MC252 oil using polyvinylpyrrolidone (PVP)-coated magnetic nanoparticles (NPs) from an oil-water mixture under a wide range of environmentally relevant conditions. In the current report, the same type of NPs were used with a high gradient magnetic separation (HGMS) technique for the rapid removal of oil from oil-water mixtures in a continuous flow system. Using a high magnetic field (0.56 T) and 1 h mixing time, fluorescence and inductively coupled plasma-optical emission spectrometer (ICP-OES) data showed approximately 85–95% oil and NP removal under all conditions. Gas chromatography–mass spectrometry (GC–MS) results show 88 and near 100% removal of alkanes (C9-C22) for experiments in the presence or absence of stainless steel wool, respectively. Continuous use over 7 h of operation (17 L oil-water mixture was treated) showed no reduction in oil and NP removal capacity. Results showed that increasing the magnetic field and inserting stainless steel wool significantly increased oil and NP removal efficiencies. This study shows that using HGMS is a promising technique for oil remediation using PVP-coated magnetic NPs.

Machinability Improvement on High Speed Ultrasonic Turning - The Effect of Tool Oscillating Direction and Tool Chip Shape

Ultrasonic cutting is a technique that can improve machinability such as fine surface, reduce tool worn out and etc. To improve processing speed of ultrasonic cutting is difficult due to the effects of tool oscillation are invalidated when cutting speed exceeds maximum tool oscillating velocity. In previous report, high speed principal direction ultrasonic turning experiments for stainless steel were carried out to improve processing speed and products quality. In ultrasonic turning, tool worn out and built up edge generation were reduced compare with ordinary turning. In this study, the effects of tool oscillating direction and tool chip shape for cutting properties of soft magnetic stainless steel were investigated. Cutting properties such as turned surface roughness, cutting force and ejected chip were compared.

IGBTレグとMOSFETレグを備えたオールメタル対応誘導加熱システム用フルブリッジ・ハーフブリッジ切り替えインバータ

An induction heating system is proposed as a new circuit topology for induction heating cookers that can be used with all metals. This system has the mechanism to drive an IGBT and a MOSFET in parallel that switch the inverter between full-bridge or modified half-bridge configuration according to the cookware material. When cookware made of a low-resistivity material such as copper or aluminum is heated, the inverter is switched to the half-bridge configuration, which turns off the IGBT leg earlier than the MOSFET leg. When cookware made of a high-resistivity material such as iron or magnetic stainless steel is heated, the inverter is switched to the full-bridge configuration. We confirmed a turn-off timing for the IGBT where the loss of the switching element in the parallel drive was minimized by an experiment. The proposed inverter effectively improved the electricity conversion efficiency for all metals pan heating with the utilized IGBT and MOSFET legs.

Effect of Cutting Speed on Ultrasonically Added Turning in Soft Magnetic Stainless Steel

Ultrasonic cutting is a technique that can improve machinability such as fine surface, reduce tool worn out and etc. To improve processing speed of ultrasonic cutting is difficult due to the effects of tool oscillation are invalidated when cutting speed exceeds maximum tool oscillating velocity. In this study, high speed principal direction ultrasonic turning experiments for soft magnetic stainless steel were carried out to investigate effects of cutting speed and products quality. Surface roughness, chip worn out and built up edge were investigated in this study. In case of ultrasonic turning, tool worn out and built up edge generation were reduced compare with ordinary turning. High speed ultrasonic cutting can improve cutting performances in phase of turned surface quality, cutting force and processing speed.

Effect of Cutting Speed on Ultrasonically Added Turning in Soft Magnetic Stainless Steel

Effect of Cutting Speed on Ultrasonically Added Turning in Soft Magnetic Stainless Steel

Modeling and simulation of cylindrical electro-chemical magnetic abrasive machining of AISI-420 magnetic steel

The objective of the present research is to simulate cylindrical electro-chemical magnetic abrasive machining (C-EMAM) process for magnetic stainless steel (AISI-420). C-EMAM is a new hybrid machining process used for high efficiency finishing of cylindrical jobs made of advanced engineering materials. The material is removed from the workpiece surface due to simultaneous effect of abrasion and electrochemical dissolution. Finite element method is used to calculate the distribution of magnetic field between the magnetic poles in which cylindrical shaped workpiece is placed. The cutting forces responsible for abrasion are calculated from the magnetic forces due to gradient of magnetic field in the working gap. The effect of electrochemical dissolution and abrasion-assisted dissolution are incorporated into the C-EMAM process model using empirical relation for average anodic current. The empirical relation is correlated with the input parameters in the present system based on experimental results. Finally a surface roughness model is developed by considering total volume of material removed with the assumption of triangular surface profile. The simulation results for material removal and surface roughness are validated using experimental results. The simulated results agree with experimental observations.

Development of Soft Magnetic Materials Prepared by Metal Injection Molding

Several kinds of soft magnetic materials prepared by metal injection molding (MIM), including pure iron, soft magnetic stainless steel, Fe-Si alloy, Fe-Co alloy, Fe-Ni alloy are introduced. The advantages of soft magnetic materials prepared by MIM are exhibited, the research status and development of soft magnetic materials prepared by MIM are reviewed.

Electromagnetic shielding mechanisms using soft magnetic stainless steel fiber enabled polyester textiles

This work studied the effects of conductivity, magnetic loss, and complex permittivity when using blended textiles (SSF/PET) of polyester fibers (PET) with stainless steel fibers (SSF) on electromagnetic wave shielding mechanisms at electromagnetic wave frequencies ranging from 30MHz to 1500MHz. The 316L stainless steel fiber used in this study had 38vol% γ austenite and 62vol% α′ martensite crystalline phases, which was characterized by an x-ray diffractometer. Due to the magnetic and dielectric loss of soft metallic magnetic stainless steel fiber enabled polyester textiles, the relationship between the reflection/absorption/transmission behaviors of the electromagnetic wave and the electrical/magnetic/dielectric properties of the SSF and SSF/PET fabrics was analyzed. Our results showed that the electromagnetic interference shielding of the SSF/PET textiles show an absorption-dominant mechanism, which attributed to the dielectric loss and the magnetic loss at a lower frequency and attributed to the magnetic loss at a higher frequency, respectively.

Electromagnetic and microwave absorption properties of magnetic stainless steel powder in 2–18 GHz

Ferritic stainless steel (FSS) powder exhibits magnetic loss, dielectric loss, and excellent resistance to corrosion and oxidation. In this study, four types of ferritic grades 409L, 410L, 430L, and 434L powders are used as magnetic fillers of microwave absorbers. Using the transmission/reflection method, the complex permittivity and permeability of the FSS-epoxy composites can be measured in 2-18 GHz. The real part of complex permittivity ɛ′ does not exhibit significant variation (∼4.0 to 6.0%) while the corresponding imaginary part ɛ″, however, exhibits relatively large variation. The magnetic susceptibility (μ′−1) of FSS-epoxy absorber is negative above 10 GHz due to the natural magnetic resonance. For FSS 430L with 40 wt.% for a thickness of 3 mm, the calculated reflection loss at 9.7 GHz reaches −11.4 dB and the corresponding 409L absorber has minimum reflection loss −5.2 dB at 11.1 GHz.