| 摘要 |
PROBLEM TO BE SOLVED: To detect shallow corner cracks with high sensitivity, regardless of the thickness of steel strips.SOLUTION: A radiation source 2 irradiates obliquely radiation to casting surfaces of the corner part A of a rectangular steel strip S which is casted through continuous casting, a detector 3 detects the radiation which is irradiated by the radiation source 2 to transmit through the steel strip S, a control unit evaluates the cracks of the corner part A using the radiation detected by the detector 3. A wedge material T is preferable to be provided on a path of radiation from the radiation source 2 to the detector 3 such that the attenuation of the radiation transmitted through the steel strip S without cracks is constant without respect to the path. A cooling mechanism are preferable to be provided for cooling the radiation source 2 and the detector 3. In addition, the radiation source 2 and the detector 3 are preferable to be housed in a case with a window portion 41 formed in the opaque window material for infrared ray to irradiate or detect radiation through the window portion 41. |
