Instruments and Control
VŠB-TU Ostrava, 6.5.2003
| Annotation of paper No. 12 |
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| Title: | The Exploitation of Picture Computer Recognition for Parameters Determination in the Laboratory Sheeting Process |
| Author(s): | HEGER, Milan, SCHINDLER, Ivo & FRANZ, Jiøí |
| Text: | A laboratory test performed by rolling of the wedge-shaped sample on plain rolls enables effectively investigate both the hot and cold deformation behaviour and formability of metallic materials, thanks to its ability to implement a wide range of height reductions (normally from 0 up to ca 80 %) in a single sample (see picture). To increase accuracy and comfort of this method the special software was developed for calculation of equivalent strain and strain rate in whatever cross section along the length of the resulting rolling stock. Calculations are based on comparison of corresponding partial volumes of the wedge-shaped initial sample and resulting rolling stock. The latter has approximately constant thickness but due to spreading strongly irregular planar shape and size. This factor considerably complicates principle application of the law of the volume preservation, when necessary calculations of partial strain components are carried out. The particular problem outlined was successfully solved by applying methods of computer analysis of a bitmap picture gained by scanning the planar shape of the sample after its rolling and straightening. The described methodology is particularly beneficial when subsurface casting defects are revealed, i.e. in case that utilization of conventional formability tests conducted by means of plastometer is virtually excluded. The article has arisen as a part of problem solving within the framework of grant reg. No. 106/02/0086 and MSM 273600001. |