Seki M.,Okayama University |
Fujii M.,Okayama University |
Kobayashi Y.,Shintokogio Ltd. |
Sato M.,Kobe Steel |
Yoshida A.,Hiroshima International University
Journal of Mechanical Science and Technology | Year: 2010
To investigate the influence of shot peening on the surface durability of powder-forged rollers, the case-hardened powder-forged rollers with a forging density of 7.5 g/cm3 treated by the single shot peening and the double shot peening were fatigue-tested under a sliding-rolling contact condition. The surface roughness, the surface hardness and the surface compressive residual stress of the rollers were increased by the shot peening. In addition, the pores near the roller surface were deformed by the shot peening. The failure mode of all the test rollers was spalling due to subsurface cracking. The fatigue lives of all the test rollers were improved by the shot peening, and that of the test roller S08, which was shot-peened with the hardest steel shots in this experimental range, was especially improved. The surface durability of the test roller S08 was also most improved by the shot peening. Cracks became difficult to occur and propagate under the roller surface since the pores near the roller surface were deformed by the stronger shot peening. In this study, double shot peening, which generally restrains the increase in surface roughness, was not particularly effective for the improvement in the surface durability of the powder-forged rollers, because the influence of tangential force on fatigue was not always great in a case of subsurface cracking. © KSME & Springer 2010. Source
Shintokogio Ltd. | Date: 2014-01-22
A sand-mold molding method for producing a molded article obtained by packing foamed sand may include stirring a binder with an aggregate to form foamed sand; forming a cavity via clamping a metallic mold closed; packing the foamed sand into the cavity of the metallic mold and then heating and solidifying the foamed sand; and opening the metallic mold partially to provide a gap in the metallic mold while maintaining the cavity.
Fujiwara Y.,Osaka Municipal Technical Research Institute |
Fujiwara Y.,Nara Institute of Science and Technology |
Koishikawa A.,Kansai University |
Koishikawa A.,UACJ Corporation |
And 6 more authors.
Journal of the Electrochemical Society | Year: 2014
Ag nanoparticle catalysts having a Ag@SnO2 core/shell structure were adsorbed from their colloidal solution on the smooth epoxy substrates conditioned with poly(diallyldimethylammonium chloride). The amounts and morphology of the adsorbed catalysts suggest the uniform monolayer adsorption and the formation of the agglomerated two-dimensional domains comprising several nanoparticles. Citrate acceleration of the adsorbed catalysts dissolved the SnO2 shell of the catalysts, and somewhat increased the size of the agglomerated domains and the surface roughness of the substrate with adsorbed nanoparticles. Electroless Cu deposition rate on the substrates with adsorbed catalysts went through a maximum at the initial stage, and then decreased to its constant value. Isolated Cu particles were deposited at the initial stage, and they coalesced to form the continuous films after the deposition rates reached the constant value. On the substrates without the citrate acceleration, Cu particles were deposited only at the beginning, due to the desorption of catalysts into the plating bath. The citrate acceleration prevented the desorption, and hence increased the catalyst availability. This led to the higher deposition rate and the faster morphology development at the initial stage because of the rapid and progressive deposition of Cu particles. © 2014 The Electrochemical Society. All rights reserved. Source
Shintokogio Ltd. | Date: 2012-02-13
A mold and die metallic material, an air-permeable member for mold and die use, and a method for making the same are provided. The mold and die metallic material is made by forming a mixed material containing stainless steel fibers with an equivalent diameter of 30-300 m and a length of 0.4-5.0 mm, and stainless steel powder, heat sintering a green body of the mixed material, and heating the sintered body thus obtained in a nitrogen atmosphere and nitrided; wherein average open pore diameter thereof is 3-50 m.
Masaki K.,Okinawa National College of Technology |
Yamashiro K.,Kobe University |
Kobayashi Y.,Shintokogio Ltd. |
Tuji T.,Shintokogio Ltd.
Zairyo/Journal of the Society of Materials Science, Japan | Year: 2014
Fatigue tests of friction stir welded (FSWed) joints of A6061-T6 aluminum alloy have been conducted with fully reversed plane bending conditions (R= -1) to investigate the effect of shot peening on the high cycle fatigue property. Shot peening was performed with two types of fine zirconia shot grid. The results showed that the fatigue strength at 107 cycles of unwelded specimens (base material) was 130 MPa and fine zirconia shot peening enhanced the strength by 10 MPa with B120 shot grid type. The fatigue lives were dramatically improved in all stress levels by the peening. On the other hand, the fatigue strength at 107 cycles of the SP treated FSWed specimens was nearly the same as that of the base material, and the fatigue lives were improved at only lower stress levels. To discuss these fatigue properties, fracture surfaces were observed and peening effects such as surface roughness, hardness and residual stress distributions were examined. ©2014 The Society of Materials Science. Source