Observation of Three Dimensional Magnetic Fields of Tool Steel (JIS-SKS93) around Vicker's Indentations

2013 ◽  
Vol 372 ◽  
pp. 265-269
Author(s):  
Katsuyuki Kida ◽  
Takashi Honda

Crack growth under cyclic loading causes failure of machine components. Non-destructive methods that can be related to plastic deformation around crack tip are necessary to study the crack growth. In the present work, a scanning Hall probe microscope (SHPM) equipped with GaAs film sensors was used to observe the magnetic fields around the plastic deformation induced by Vicker's indentations in tool steel specimens (SKS93, JIS B 4404: 2006, equivalent to AISI W4 tool steel). The magnetic field around a 2.94N-indentation was compared to that of a 294N-indentation. It was found that the decrease in the magnetic fields depends on the plastic deformation size.

2013 ◽  
Vol 307 ◽  
pp. 144-148 ◽  
Author(s):  
Katsuyuki Kida ◽  
Megumi Uryu ◽  
Takashi Honda ◽  
Teruaki Shimoji ◽  
Edson Costa Santos ◽  
...  

Fatigue failure of machine components is caused by cyclic load. Non-destructive observation methods that can be related to stress are necessary to study the fatigue phenomena. In the present work, a three-dimensional scanning Hall probe microscope (SHPM) equipped with GaAs film sensors was used to observe the fundamental features of the magnetic fields in a tool steel specimen (SKS93, JIS B 4404: 2006, equivalent to AISI W4 tool steel) during tensile loading. The nature of the magnetic fields during tensile loadings of 430μstrain and 640μstrain was observed using the SHPM. It was found that the magnetic fields decrease due to the tensile loading.


2017 ◽  
Vol 741 ◽  
pp. 105-109
Author(s):  
Katsuyuki Kida ◽  
Ariyasu Yadoiwa ◽  
Takuto Yamada ◽  
Ryosuke Kawamura ◽  
Masayuki Ishida

Non-destructive stress measurement methods have been developed. However, there are a few approaches into the effect of stress direction on the nondestructive physical factors. In the present work, a non-destructive and non-contact method using three-dimensional magnet microscopy was applied to stress evaluation of an as-received tool steel (JIS, SKS93). Three-dimensional components of magnetic fields were observed using a scanning Hall probe microscope in order to find the important component which was related to the tensile stress. The observations were carried out under the tensile stress that was less than the yielding stress of the material. It was found that the magnetic field component that was parallel to a tensile loading direction was strongly correlated to stress values.


2012 ◽  
Vol 566 ◽  
pp. 103-108 ◽  
Author(s):  
Katsuyuki Kida ◽  
Megumi Uryu ◽  
Takashi Honda ◽  
Edson Costa Santos ◽  
Kenichi Saruwatari

Tribological failure of machine components, such as wear and flaking failure is caused by contact stress concentration. However, observation of stress under contact load is a difficult task. Non-destructive methods that can be related to contact conditions are necessary to study and understand the phenomena caused by the contact stresses. In the present work, a scanning Hall probe microscope (SHPM) equipped with a GaAs film sensor was used to observe the three-dimensional magnetic fields in a long square bar specimen (JIS-SUJ2) before and after contact tests at 196N. It was found that the changes in the three-dimensional magnetic fields caused by spherical Hertzian contact are not affected by the location of the magnetization point on the specimen's surface.


2012 ◽  
Vol 457-458 ◽  
pp. 578-585 ◽  
Author(s):  
Katsuyuki Kida ◽  
Megumi Uryu ◽  
Takashi Honda ◽  
Edson Costa Santos ◽  
Kenichi Saruwatari

Failure of dies and molds is caused by wear and deformation during the metal sheet forming process. Die wear takes various forms, and the contact conditions in die-parts affect the strength of the components. Non-destructive methods that can be related to contact conditions are necessary to study and understand the phenomena caused by the contact stresses. In the present work, a newly developed scanning Hall probe microscope (SHPM) equipped with a GaAs film sensor was used to observe the three-dimensional magnetic fields in tool steel plates before and after contact tests at room temperature in air. It was found that the intensity of three-dimensional magnetic fields is only slightly affected by the spherical Hertzian contact. However, all of the three-dimensional components of the magnetic fields change significantly. The extent of the changes depends not on the distribution of stress under spherical Hertzian contact but on the initial distribution of the magnetic fields.


2012 ◽  
Vol 457-458 ◽  
pp. 884-890
Author(s):  
Megumi Uryu ◽  
Katsuyuki Kida ◽  
Takashi Honda ◽  
Kenichi Saruwatari ◽  
Edson Costa Santos ◽  
...  

Fatigue failure of machine components occurs when cracks form in the stress concentration area and propagate under continued loading during component work. In order to understand the relation between the phenomena of stress concentration and crack propagation, non-destructive evaluation methods using in-situ measurements in the stress concentration areas are necessary. In the present work, a scanning Hall probe microscope (SHPM) equipped with a GaAs film sensor was developed and the three dimensional magnetic fields were observed at room temperature in air. The effect of stress on the changes in the magnetic field in steel components is reported. A steel specimen (JIS SKS93) embedded in acrylic resin were strained at different loads and the magnetic field before and after straining were observed. The obtained magnetic images clearly corresponded with the shape of the steel plate. It was possible to measure the changes in the magnetic field of the steel sample after straining under tensile loading, by neutralizing the initial magnetic field of the specimens prior to testing.


2011 ◽  
Vol 83 ◽  
pp. 210-215 ◽  
Author(s):  
Takashi Honda ◽  
Katsuyuki Kida ◽  
Edson Costa Santos ◽  
Hitonobu Koike ◽  
Justyna Rozwadowska ◽  
...  

Fatigue failure of steel occurs when cracks form in a component and continue to grow to a size large enough to cause fracture. In order to understand the strength of a steel component, it is important to locate these cracks. We developed a scanning Hall probe microscope (SHPM), equipped with GaAs film sensors to observe fatigue cracks at room temperature in air while they were growing. In our previous works [1,2], the correlation between crack growth and magnetic field in high carbon tool steels (JIS SKS93 and JIS SUJ2) were determined. We also reported the sensitivity of the SHPM equipped with a three-dimensional line-probe that was developed to decrease the sensor gaps. By using the line-probe sensor we succeeded to measure the magnetic flux density distributions in very close proximity to the specimen’s surface. However, in order to further understand the relation between magnetic flux density and crack growth, other materials, microstructures and fatigue test conditions should be evaluated. In the present work, we focus on the effect of stress ratios on the changes of the magnetic flux density in annealed carbon tool steel.


2011 ◽  
Vol 217-218 ◽  
pp. 1297-1302 ◽  
Author(s):  
M. Uryu ◽  
Katsuyuki Kida ◽  
Takashi Honda ◽  
Edson Costa Santos ◽  
K. Saruwatari

Fatigue failure of steel occurs when cracks form and grow in the material’s stress concentration area. In order to understand the relation between stress concentration and crack propagation phenomena, non-destructive evaluation methods that can be related to in-situ measurements around the stress concentration area are necessary. In the present work, we developed a scanning Hall probe microscope (SHPM) equipped in a GaAs film sensor and observed three dimensional magnetic fields at room temperature in air. Medium carbon low alloy steels specimens (JIS, S45C) were used in the experiments. Only the area around the artificial slit had been magnetized and the effect of the magnetization area on the artificial slit was observed.


2017 ◽  
Vol 748 ◽  
pp. 386-390
Author(s):  
Tatsurou Nakashima ◽  
Katsuyuki Kida

Crack propagation around the stress concentration area causes fatigue failure. Non-destructive method is necessary for monitoring structure fatigue before destruction. We focused on a magnetic non-destructive evaluation method for crack growth. In order to understand the relation between crack propagation and changes in magnetic flux density, we observed the position of the positive and negative magnetic flux density distributions around the crack of tool steel (SCM440) plate using a scanning Hall probe microscope (SHPM). We found that the vertical component of the three-dimensional magnetic flux density moved as the crack growth. Furthermore, the magnetic component which is parallel to the tensile stress appeared just before destruction of the specimen.


Author(s):  
Vladislav Sevostianov

The paper presents the concept of self-diagnosing smart bolts and its experimental validation. In the present research such bolts are designed, built, and experimentally tested. As a key element of the design, wires of Galfenol (alloy of iron and gallium) are used. This material shows magnetostrictive properties, and, at the same time, is sufficiently ductile to follow typical deformation of rock bolts, and is economically affordable. Two types of Galfenol were used: Ga10Fe90 and Ga17Fe83. The wires have been installed in bolts using two designs — in a drilled central hole or in a cut along the side — and the bolts were tested for generation of the magnetic field under three-point bending loading. To measure the magnetic field in the process of deformation, a magnetometer that utilizes the GMR effect was designed, built, and compared with one utilizing the Hall effect. It is shown that (1) magnetic field generated by deformation of the smart bolts at the stress level of plastic deformation is sufficient to be noticed by the proposed magnetometer; however, the magnetometer using Hall effect is insufficient; (2) Ga10Fe90 produces higher magnetic fields than Ga17Fe83; (3) the magnetic field in plastically bended bolts is relatively stable with time.


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