SURFACE FLAW DETECTION DEVICE AND SURFACE FLAW DETECTION METHOD

• Main Authors: NAKAMURA HIROSHI, KOBAYASHI MASAYOSHI, SUGYO SHOJI, KATO MASAKAZU
• Format: Patent
• Language: English; Japanese
• Published: 19.01.2015
• Subjects: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS; MEASURING LENGTH, THICKNESS OR SIMILAR LINEARDIMENSIONS; PHYSICS; TESTING

PROBLEM TO BE SOLVED: To provide a surface flaw detection device capable of surely detecting, online, a surface flaw of a concave-shaped rolled material that occurs when manufacturing a steel bar with a rolling machine, and to provide a surface flaw detection method.SOLUTION: A surface flaw detection device 1 according to the invention detects a surface flaw of a rolled round steel bar material W, and comprises: profile extraction means 2 that extracts a two-dimensional profile shape of a cross-section surface cut in a direction vertical to an axial length direction of the rolled round steel bar material W during conveyance; curvature calculation means 3 that applies second order differential to the two-dimensional profile shape extracted by the profile extraction means and obtains a value of curvature at an outer circumference of the rolled round steel bar material W; and determination means 4 that determines occurrence of the surface flaw on a surface of the rolled round steel bar material W when the value of curvature calculated by the curvature calculation means 3 is greater than a preset threshold. 【課題】圧延機で棒鋼を製造する際に発生する凹形状を有する圧延材の表面疵をオンラインで、且つ確実に検出することができる表面疵検出装置、及び表面疵検出方法を提供する。【解決手段】本発明の表面疵検出装置１は、棒鋼圧延材Ｗの表面疵を検出する表面疵検出装置１であって、搬送中の前記棒鋼圧延材Ｗの軸長方向に対して垂直方向に切断した断面の２次元プロファイル形状を抽出するプロファイル抽出手段２と、プロファイル抽出手段２で抽出された２次元プロファイル形状を二階微分して、棒鋼圧延材Ｗの外周囲における曲率の値を求める曲率算出手段３と、曲率算出手段３で算出された曲率の値が予め設定されている閾値より大きい場合、棒鋼圧延材Ｗの表面に表面疵が発生していると判定する判定手段４と、を有する。【選択図】図２