High-Tc superconducting quantum interference device observation of heat-affected zone in a spot-welded Fe–Cr–Ni system

Watanabe, Yoshihiko; Kang, Sungwon; Chan, J.W.; Morris, J.W.; Clarke, John

doi:10.1063/1.1599039

Cited by 11 publications

(3 citation statements)

References 10 publications

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“…Therefore, the specimen temperature should ideally be measured by many thermocouples attached to the specimen surface by spot welding. However, recently it was found that a heat affected zone (HAZ), 13 in which only the austenite phase exists, was produced in the deformed stainless steel by spot welding. To avoid unnecessary experimental error, therefore, a movable thermocouple was used to measure the thermal gradient within the specimen.…”

Section: Methodsmentioning

confidence: 99%

Magnetically graded materials fabricated by inhomogeneous heat treatment of deformed stainless steel

Watanabe¹,

Momose²

2004

Ironmaking & Steelmaking

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The present work was undertaken with the objective of developing a magnetically graded material by a reverse martensitic transformation (RMT) technique in a controlled manner. Tensile deformed SUS type 304 stainless steel was annealed within a temperature gradient to introduce the reverse martensitic transformation inhomogeneously. The magnetisation distributions within specimens were evaluated using a vibrating sample magnetometer. It was found that the desired saturation magnetisation gradient was formed in the magnetically graded material fabricated by the RMT technique. Therefore, by controlling the thermal gradient in the furnace very carefully, it is possible to obtain a magnetically graded material with a suitable gradient of magnetisation using the a9-c reverse transformation in SUS 304 stainless steel.

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Section: Methodsmentioning

confidence: 99%

Magnetically graded materials fabricated by inhomogeneous heat treatment of deformed stainless steel

Watanabe¹,

Momose²

2004

Ironmaking & Steelmaking

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“…Scanning SQUID microscopes are used to investigate the spatial distributions of magnetic fields on sample surfaces; a SQUID of small washer size is used as a magnetic field detector [1][2][3][4]. It has been applied in various research areas, e.g., superconductivity, magnetism, material engineering, immunoassay, and nondestructive evaluation of metallic parts [5][6][7][8][9][10][11][12][13][14]. The efforts at enhancement of the spatial resolution otherwise limited by the SQUID loop size include the adoption of a small SQUID called a microSQUID [15], the laser excitation method [16], and the use of a flux-guiding needle [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Investigation of a magnetic flux-guide for a HTS scanning superconducting quantum interference device microscope

Baek¹,

Moon²,

Lee³

et al. 2004

Supercond. Sci. Technol.

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A magnetic flux-guide in the form of a sharp needle is known to enhance the spatial resolution of the scanning SQUID microscope. We investigated the properties of a soft ferromagnetic tip as a flux-guide by measuring the local field of the tip end. The effects of the flux-guide, such as the transmission of a magnetic signal, length dependence, and nonlinear distortion, were observed. We also present the design and construction of a HTS scanning SQUID microscope with a flux-guide and a planar gradiometer. The gradiometer with a flux-guide is an appropriate solution for improving the performance of the scanning SQUID microscope with a flux-guide as regards the prevention of external field noise without magnetic shields.

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“…For the analysis of the weld zone microstructure, optical microscope (OM), electron microscope, X-ray diffraction techniques, Mössbauer analysis and a superconducting quantum interference device (SQUID) microscope have been widely used. [2][3][4][5] The a to g phase transformation occurring in the HAZ of AISI 1005 steel ((0.05C, 0.31Mn, 0.18Si, 0.11Ni, 0.10Cr; by mass percent) welds was studied by in situ spatially resolved X-ray diffraction (SRXRD) experiments. 5) Numerical study on the effect of electrode force in small-scale resistance spot welding was reported by Chang and Zhou.…”

Section: Introductionmentioning

confidence: 99%

Effect of Magnetic Field on Weld Zone by Spot-welding in Stainless Steel

2006

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Spot welding is performed through a resistance welding process in which the components to be welded are clamped between two electrodes supplying heat current. It is known that a weld fusion zone and a heat-affected zone (HAZ), which experience high temperature followed by rapid cooling to room temperature, exhibit very different microstructures, compared with those of base materials. The microstructure of the weld fusion zone and HAZ (weld zone) is influenced by many factors such as chemical composition, welding condition and peak temperature. In this study, the effect of magnetic field on HAZ in spot welded stainless steel was studied. For this purpose, deformed and undeformed 301 type stainless steel (Fe17mass%Cr-7mass%Ni-0.1mass%C-0.5mass%Si-0.99mass%Mn) samples with aЈ martensite phase and g austenite phase, respectively, were spot-welded under a magnetic field up to 2 T. The welded surfaces and the cross-section planes were examined using an optical microscope. It was found that the area of HAZ was increased with increasing magnetic field, as well as the heat input power. Moreover, the area of weld zone in deformed stainless steel is larger than that in undeformed stainless steel. Based on the experimental results, the effect of magnetic field on HAZ in spot-welded stainless steel was discussed.KEY WORDS: stainless steel; phase transformation; welding; magnetic field; process control; Lorentz force.ISIJ International, Vol. 46 (2006), No. 9, pp. 1292-1296 experimental results, the effect of magnetic field on weld zone in spot-welded stainless steel was discussed. ExperimentalThe specimen for the present investigation was a SUS 301 type stainless steel with the dimensions of 10 mmϫ 10 mmϫ1 mm. The chemical composition (mass%) of the stainless steel studied was: Cr 17.0, Ni 7.0, C 0.1, Mn 0.99, Si 0.5 and Fe bal. After austenitization at 1 323 K (1 050°C) for 2 h, some specimens were compression deformed at 77 K to introduce the aЈ martensite phase. Magnetic measurement of deformed specimen was conducted in a vibrating sample magnetometer (VSM; BHV-55, Riken Denshi Co. Ltd.) at room temperature with a maximum magnetic field of 1 T to calculate the amount of the aЈ martensite phase. Since the saturation magnetization of the deformed specimen was 37 emu/g, the amount of aЈ martensite phase in the deformed specimen was estimated to be about 20-25 % by using the saturation magnetization of SUS 304 type stainless steel.Heating by a spot welding machine under a magnetic field was carried out for both deformed and undeformed samples with aЈ martensite and austenite g phases, respectively. Hereafter, this operation will be called as "welding", although no material was jointed with the stainless steel sample. Heat input power and maximum magnetic field is 10 W s and 2 T, respectively. Magnetic field was applied perpendicular to the spot welding direction, as shown in Fig. 1.The welded surfaces were examined using an OM. To observe the weld zone in the deformed stainless steel with aЈ martensite phase, a magnetic etchin...

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High-Tc superconducting quantum interference device observation of heat-affected zone in a spot-welded Fe–Cr–Ni system

Cited by 11 publications

References 10 publications

Magnetically graded materials fabricated by inhomogeneous heat treatment of deformed stainless steel

Magnetically graded materials fabricated by inhomogeneous heat treatment of deformed stainless steel

Investigation of a magnetic flux-guide for a HTS scanning superconducting quantum interference device microscope

Effect of Magnetic Field on Weld Zone by Spot-welding in Stainless Steel

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