| 摘要 |
PURPOSE:To grind a surface flaw with very good efficiency by providing a control means for selectively using a grinder according to the distribution of flaw length to grind a surface flaw. CONSTITUTION:A test for a surface flaw of a billet is made by a magnetic particle testing device, and the test results of the flaw length and flaw depth are recorded corresponding to the billet position. An arithmetic unit 11 calculates the frequency of flaw length on every billet according to the surface flaw length information from the magnetic particle testing device to obtain where the maximum frequency exists among such three classifications that the flaw length is less than about 50mm, about 50m and more, and less than about 100mm and about 100mm or more. A grinder select device 12 selects a grinder to be assigned according to the above result, and the flaw length and flaw depth information matching the longitudinal and cross-direction positions of a billet is transmitted to the grinder. |
