A compact accelerator-based neutron source has been lately discussed on engineering applications such as transmission imaging and small angle scattering well reflectometry. However, nobody considers using it for diffraction experiment because of its low flux. In this study, therefore, the experiments are carried out Riken Accelerator-driven Compact Neutron Source (RANS), to clarify capability diffraction. The pattern from a ferritic steel was successfully measured by suitable arrangement...

Water under a film of paint in corroded steels was visualized using thermal neutrons at the RIKEN-accelerator-based compact neutron source. Two painted plate samples made normal steel and corrosion-resistant alloy were prepared. Both scratched on surface then subjected to cyclic corrosion test generate blisters caused by under-film corrosion. They soaked water for 2 h removed from water. Time dependences distribution observed transmission imaging method first time. The sample contained less...

This study established delayed fracture stress thresholds for punched surfaces of two ultra-high-strength steel sheets, JSC1180Y and 22MnB5. Punched exhibit deterioration in ductility high residual stresses, thereby lowering thresholds. Consequently, identifying such degraded is essential the early detection fractures industrial applications. To address this challenge, we newly developed a special in-plane bending test that imposes arbitrary stresses on while simultaneously subjecting them...

In order to improve the instrumental accessibility of neutron diffraction techniques, many emerging compact sources and in-house diffractometers are being developed, even though precision level experiments performed on such instruments was thought be incomparable with that large-scale facilities. As a challenging project, RIKEN accelerator-driven source (RANS) employed here establish technical environment for texture measurements, recalculated pole figures orientation distribution functions...

Views Icon Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Twitter Facebook Reddit LinkedIn Tools Reprints and Permissions Cite Search Site Citation Masato Takamura, Ayako Fukui, Hiroshi Yano, Takayuki Hama, Hideyuki Sunaga, Akitake Makinouchi, Motoo Asakawa; Investigation on Twisting Side Wall Opening Occurring in Curved Hat Channel Products Made of High Strength Steel Sheets. AIP Conf. Proc. 22 August 2011; 1383 (1): 887–894....

This study investigated the twisting phenomenon in curved hat channel products made of dual-phase 980-MPa-class high-tensile-strength steel sheets. The stroke returning deep drawing (SRDD) method was proposed to deal with twisting. In this new method, after punch reaches bottom dead point, it returns a certain height without blank holder being removed. With application SRDD hardly occurred, but sidewall curl increased. A two-step then reduce products. process is carried out two steps under...

著者らは RANS を用いた回折測定を行い

Neutron diffraction profile analysis using the whole fitting method is useful for obtaining microscopic information on metallic materials. To determine an appropriate approach reasonable and non-arbitrary results, we applied line analyses Convolutional Multiple Whole Profile (CMWP) to patterns obtained Engineering Materials Diffractometer (TAKUMI, BL19) at Life Science Facility (MLF) of Japan Proton Accelerator Research Complex (J-PARC). The tensile specimens 780 MPa grade bainitic steel...

Neutron diffraction is a powerful non-destructive method for evaluating the microscopic structure and internal stress of metal plates as bulk average. Precise neutron measurements with high-intensity beam have already been carried out at large-scale facilities. However, it not easy to provide users enough experimental opportunities. We are working on upgrading diffractometer techniques time-of-flight enable RIKEN accelerator-driven compact source (RANS). To improve resolution, delayed...

Neutron diffraction is well known to be a useful technique for measuring bulk texture of metallic materials taking advantage large penetration depth the neutron beam. However, this has not been widely utilized measurement because facilities like reactor or accelerator are required in general. In contrast, RANS (Riken Accelerator-driven Compact Source) developed as source which can used easily laboratories. study, evolution steel sheets with plastic deformation was successfully measured using...

Stress relaxation, which occurs during holding at the bottom dead center in press forming, affects formability. Because is completed within several seconds, it important to predict stress relaxation behavior of first few seconds after start holding. The purpose this study propose a model, material parameters are obtained from tensile tests, decreasing early stage steel sheets. We constructed model by modifying Kocks-Mecking based on following assumptions: room temperature due slip motion...

In this study, the effect of tool-modeling accuracy on a finite-element simulation square-cup deep-drawing process is examined. First, tool modeling using conventional approach, in which polyhedral surfaces are used, compared with that an alternative quadratic parametric proposed by Nagata [Nagata, Comput. Aided Geom. D 22 (2005) 327–347] (Nagata patch) used. It clear patch yields much more accurate geometry than approach regard to shape and normal vectors tool. Next, simulations carried out...

The specimens (980 MPa-grade dual phase steel sheets) were stretched until the pre-defined strain was obtained. Then held at and measured change of stress durng holding. We investigated effects rate starting time holding whether during could be described by Krempl model. following results First, drop increased with increase time. On other hand, not affected Second, initial relaxation rate. However, this dependency to diminished as became long enough roughly more than 100 s. Third, obtained...

Chloride attack is a serious problem that decreases the durability of concrete structures bridges and highways. A compact neutron salt meter with a252Cf source germanium (Ge) gamma-ray detector based on prompt activation analysis (PGNAA) has been proposed to determine chlorine concentration in structures. The Optimization dimensions its components, such as polyethylene (PE) moderator, graphite reflector, lead shield, well positions 252Cf Ge performed make it highly sensitive for detection...

Stress relaxation is the phenomenon where stress of materials decreases under constant strain. In several previous studies, it was found that makes uniform elongation larger, showing a possibility this can be utilized to increase forming limit in combination with flexible slide motion servo press. However, has not yet been sufficiently clarified. Authors previously investigated behavior by applying models described as an elasto-viscoplasticity behavior. unified and quantitative description...

Treatment of contact problems between sheet and tools is one the most difficult to deal with in metal forming simulations. This paper describes a new algorithm for discretization change “averaged tool normal” which calculated by averaging normals defined on all adjacent elements. The proposed was implemented into STAMP3D, static explicit program dedicated Simulations draw bending process were performed normalized norm non-equilibrated forces due compared original result obtained algorithm....

High-strength steel sheets are increasingly applied to automotive bodies for weight reduction in order meet the needs reduced environmental impact. However, dimensional defects resulting from springback serious issues, and effective methods of predicting reducing such required. In this study, we propose validate advantage stroke-returning deep-drawing process, which stroke is returned specified depth after drawing bottom dead point. The following results were obtained. Firstly, by twist...

We studied the feasibility of a portable salt-meter incorporating prompt gamma neutron activation analysis with californium-252 source to meet urgent demands for non-destructive methods without pre-processing in large bulk materials such as concrete structures. This technique is aiming at chloride ion concentration structures depth profile from surface steel bar. From portability point view, adopted and we have performed preliminary experiment simulations simple geometry. In this paper,...

To characterize the dose rate distribution in an experimental hall of a RIKEN accelerator-driven compact neutron source (RANS) based on 9 Be(p, n) reaction with 7 MeV proton injection, systematical measurements and calculations for gamma-ray rates by GEometry ANd Tracking (GEANT), Particle Heavy Ion Transport code System (PHITS), Monte Carlo N-Particle (MCNP) codes were performed.Calculations always underestimated when beam loss effect was not considered.Relatively good agreements observed...