Papers by Keyword: Carbon Tool Steel

Abstract: 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.

Abstract: 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 films sensors and observed fatigue cracks at room temperature in air while they were growing. In our previous works, we determined the correlation between crack growth and magnetic field in high carbon tool steels (JIS SKS93 and JIS SUJ2). 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.

Abstract: High accuracy and high efficiency machining of micro parts such as a contact probe for a current inspection of semiconductor is increasingly demanded. In this study, we have focused on a micro cutting technology of a carbon tool steel which is a typical material for a contact probe. In order to put the precision cutting of the high strength material into practice, it is essential to understand the micro cutting phenomenon such as the surface texture, the tool wear with small depth of cut and low cutting speed. Then, the precision cutting experiments of a carbon tool steel (SK105) by titanium carbide and ultra-fine grained tungsten carbide tools were carried out with an ultra-precision cutting machine. It was found that the feed rate, the cutting speed and the edge sharpness of tool significantly influence the surface finish.