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

Watanabe, Yoshihiko; Momose, I.

doi:10.1179/030192304225011043

Cited by 6 publications

(3 citation statements)

References 13 publications

(19 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The starting and finishing temperatures of the reverse martensitic transformation in 304 stainless steel are reported to be 450°C and 900°C, respectively. 20) Since the reverse transformation is completed very quickly, the phenomena shown in Fig. 2(a) can be explained by the fact that the ferromagnetic aЈ martensite phase transformed into the paramagnetic austenite g phase by the heat generated by the spot welding.…”

Section: Figurementioning

confidence: 99%

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

2006

View full text Add to dashboard Cite

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...

show abstract

Section: Figurementioning

confidence: 99%

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

2006

View full text Add to dashboard Cite

show abstract

“…In earlier studies, the inhomogeneous deformation had been introduced by tensile (Watanabe et al, 1993) or rolling deformation or compression deformation (Watanabe and Sakai, 2003) of wedge-shaped samples. The reverse martensitic transformation technique was applied for the rectangular shaped specimen (Sakai et al, 1999;Watanabe and Momose, 2004) and for the fiber shaped specimen (Tanaka and Watanabe, 1999).…”

Section: Magnetically Graded Materialsmentioning

confidence: 99%

“…In the range of the reverse martensitic transformation start and finish temperatures, the amount of saturation magnetization due to the martensite phase decreases with increasing temperature. Heat treatment in a thermal gradient also changes the saturation magnetization, with an amount of the martensite phase that depends on the local temperature (reverse martensitic transformation technique (Sakai et al, 1999;Tanaka and Watanabe, 1999;Watanabe and Momose, 2004)). …”

Section: Introductionmentioning

confidence: 99%

Magnetically Graded Ni3Al Fabricated by Inhomogeneous Deformation and Heat Treatment

Watanabe

Fukada

Hosoda

2006

Journal of Intelligent Material Systems and Structures

View full text Add to dashboard Cite

The magnetic properties of Ni 3 Al intermetallic compound are influenced by the degree of order through the change of the number of Ni-Ni bonds at antiphase boundaries (APB). Since the degree of order can be changed by plastic deformation and heat treatment, the fabrication of magnetically graded smart materials based on Ni 3 Al intermetallic compound has been carried out by the following two methods: (1) an inhomogeneous compressive deformation using a wedge-shaped specimen and (2) an inhomogeneous heat treatment with temperature gradient. The magnetic properties are measured by the vibrating sample magnetometer (VSM) technique. It has been found that the magnetically graded smart materials with susceptibility gradient are successfully fabricated by either the compression deformation of the wedge-shaped Ni 3 Al or the inhomogeneous heat treatment. It has also been found that the degree of long-range order, S, varies depending on the position of the specimen. The susceptibility gradient is correlated with the gradient of the degree of longrange order S.

show abstract