Soft Magnetic Stainless Steel Research Articles

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.

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.

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

Corrosion Resistance of a Free-Cutting Soft-Magnetic Stainless Steel in Pure Water

Corrosion Resistance of a Free-Cutting Soft-Magnetic Stainless Steel in Pure Water

Magnetic-Actuated Stainless Steel Scanner for Two-Photon Hyperspectral Fluorescence Microscope

We present a fluorescence two-photon laser scanning microscope that uses a soft-magnetic stainless steel microscanner to generate a 2-D Lissajous scanning pattern. The wide-scanning low-voltage driven gimbaled torsional stainless steel microelectromechanical systems (MEMSs) scanner is designed and then fabricated using electrical discharge machining. This technology offers unique advantages by allowing larger mirror surface areas (4 mm \(\times5\) mm) to enhance the fluorescence collection efficiency at low incoming signal level, and providing a rapid prototyping and low-cost alternative to silicon-based MEMS devices, particularly when large displacements and large field of view are required. A maximum total optical scan angle (TOSA) of 20.6° at 112 Hz for a drive power of 200 mW is required for the slow-scan movement, whereas the fast-scan movement occurs at the resonance frequency of 1268 Hz and has a TOSA of 26.6° using a drive power of 400 mW. The soft-magnetic microscanner incorporated in the two-photon hyperspectral fluorescence microscope demonstrates its applicability in two-photon hyperspectral imaging of circulating cancer cells, stem cells, and biological tissue with extrinsic fluorophores.

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.

水圧用直動形高速電磁弁の開発

When tap water is used as a pressure medium, the structure and material of an oil hydraulic high-speed solenoid valve can not be used because internal leakage and rust can occur. Accordingly, the authors have proposed a novel water hydraulic high-speed solenoid valve. This study is mainly concerned with the development of direct-driven water hydraulic high-speed solenoid valve. Through the investigation of soft magnetic material which has anti-corrosion and low eddy current characteristic, a solenoid design method using soft magnetic stainless steel instead of soft magnetic iron was established. Furthermore, a high-speed driving circuit, which compulsively imprints over-excitation voltage and demagnetization voltage onto the solenoid, is used in order to reduce the switching time of the water hydraulic high-speed solenoid valve. From the linear characteristics of Duty and mean flow, as well as fast switching time within 1.5ms, the validity of solenoid and direct driven valve design method for water hydraulics is verified.

New type of Pb-free Machinable Soft-Magnetic Stainless Steels with Dispersed Titanium Carbo-Sulfide

Although conventional free-cutting soft-magnetic stainless steel contains Pb to facilitate machining, the replacement and elimination of Pb is required from the standpoint of environmental protection. In this article, the authors report the development of new Pb-free machinable soft-magnetic stainless steels in which titanium carbo-sulfide is used as an inclusion. The microstructural evolution, magnetic properties, corrosion resistance, machinability and mechanical properties of these new free-cutting stainless steels are presented.

快削電磁ステンレス鋼の溶接性に及ぼすＴｉ炭硫化物の影響

Soft-magnetic stainless steels have been used for high precision equipment. Their good machinability is rendered by Pb and/or MnS dispersed in them. From the viewpoint of health, Pb is an undesirable element. And MnS deteriorates the corrosion resistance and cold formability. A titanium carbosulfide, Ti4C2S2, is thermodynamically more stable than MnS and it is considered to replace MnS. Effect of titanium carbosulfide on weldability of a soft-magnetic stainless steel has been investigated. Regarding a laser-welded joint of this steel plate and Type304 stainless steel plate, weld bead appearance and shape of penetration were equivalent to those of conventional stainless steel. There were no welding cracks in the weld bead, and there were few microporosities in the case of lower heat input than 0.225kJ/cm. Furthermore, welded joint was ruptured in base metal or HAZ of Type304 stainless steel plate in tensile test, so the mechanical property of welded joint was excellent.

Soft magnetic stainless steel resists corrosion

Soft magnetic stainless steel resists corrosion

軟磁性ステンレス鋼のパルス応答性に及ぼすCrおよびAl量の影響

Soft magnetic stainless steels are used for the yoke in fuel injectors to require a good corrosion resistance. The pulse response property of the yoke material is essential to the dynamical performance of fuel injectors. However, effects of alloying elements on the property is not clear.An equipment measuring the pulse response property is devised to investigate various Fe-Cr-Al alloys including commercial magnetic stainless steels. The ring specimens used in the equipment are provided with a slit to simulate the injector system. The magnetic response to a magnetizing pulse current is measured so that the relaxation time can be obtained to estimate the pulse response property.The results obtained show that the relaxation time mainly depends on the specific resistance of the alloy specimens. It decreases with the increase in the specific resistance, though the magnetic properties such as the coercive force are hardly affected. As a result, it has been found that a soft magnetic stainless steel of 10Cr-3Al composition is recommendable to the yoke material, better than 45Ni-permalloy or 12Cr-0.8Si-0.3Al stainless steel previously used.