Park M.,Korea Institute of Industrial Technology |
Lee C.,Korea Institute of Industrial Technology |
Lee J.,Korea Institute of Industrial Technology |
Lee I.,Korea Institute of Industrial Technology |
And 3 more authors.
International Journal of Precision Engineering and Manufacturing | Year: 2016
Recently, there is an increasing commercial interest in manufacturing rings with a complicated cross-sectional shape directly by a metal forming process instead of by machining. Profile ring rolling is one of the advanced metal forming technologies to manufacture large or small seamless profile rings. Compared with plain ring rolling, profile ring rolling can yield considerable savings in material cost and a shorter cycle time for additional machining. In this study, a profile ring rolling process for producing large-scale profile rings with an L-section for construction machine parts is developed. The manufacturing process of large-scale profile rings with L-section consists of a forging stage and a profile ring rolling stage. In the forging stage, the raw material is formed to initial blanks for profile ring rolling. The forged initial blanks are then formed to the final product shape in the profile ring rolling process, which is designed to occur in a single pass to minimize the cycle time. The design of the blank shape is very important, to enable the design of a profile ring rolling process without forming defects, such as fishtails, underfilling, and distortion of the ring. A finite-element (FE) analysis was performed to optimize the blank ring shape, with the objective of minimizing forming defects. After determination of the initial blank shape, the effects of process variables such as feed conditions of mandrel and axial rolls on the final product shape was investigated to improve the dimensional accuracy. Also, forming experiments were conducted based on the results of the FE analysis. The experimental results were in good agreement with the results of the FE analysis. © 2016, Korean Society for Precision Engineering and Springer-Verlag Berlin Heidelberg. Source
Kim J.,Korea University |
Joo Y.-A.,Korea University |
Lee Y.J.,Gyeonsang National University |
Kim J.,Gyeonsang National University |
And 2 more authors.
Journal of Asia-Pacific Entomology | Year: 2016
Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) is an economically important pest, which harms various kinds of important agricultural crops, such as cotton and paprika. Effects of ionizing radiation (gamma, x-ray, and electron beam radiation) at 300. Gy on 4th to 5th instar larvae of H. armigera were tested on the post-treatment development of the larvae to identify the effective quarantine treatment dose. A few adults emerged out of the pupae developed from larvae irradiated with gamma ray and electron beams, while no adults emerged from the larvae irradiated with x-rays. Mortalities caused by gamma, X-ray, and electron beam radiation were 99.05%, 100%, and 99.93%, respectively, with no significant difference from that caused by methyl bromide (MeBr) fumigation (99.83%). Our results indicate that ionizing radiation could be recommendable as an alternative to MeBr and a phytosanitary treatment for quarantine. A treatment dose of 300. Gy is adaptable as a quarantine treatment to H. armigera larva in paprika fruit for prevention of pupation and adult emergence. © 2015 Korean Society of Applied Entomology, Taiwan Entomological Society and Malaysian Plant Protection Society. Source