NONDESTRUCTIVE INSPECTION METHOD FOR HIGH MANGANESE CAST STEEL

To provide a nondestructive inspection method for high manganese cast steel, allowing for quick inspection whether metallographic structure is micronized, using simple configuration for material such as high manganese cast steel having large crystal grains.SOLUTION: The nondestructive inspection method for high manganese cast steel includes an ultrasonic transmission step, an ultrasonic reception step, and a micronization determination step. In the ultrasonic transmission step, ultrasonic waves are transmitted into an interior of the high manganese cast steel from a first surface which is the surface of the high manganese cast steel to be inspected toward a second surface which is a surface located on the opposite side of the first surface with the metallographic structure of the high manganese cast steel interposed between the first and second surfaces. In the ultrasonic reception step, the ultrasonic wave transmitted in the ultrasonic transmission step or the reflected wave of the transmitted ultrasonic wave is received. In the micronization determination step, it is determined whether the metallographic structure of the high manganese cast steel is micronized or not on the basis of the level of the ultrasonic wave received directly or the level of the reflected wave reflected from the second surface out of the wave received in the ultrasonic reception step.SELECTED DRAWING: Figure 3 【課題】結晶粒が大きい高マンガン鋳鋼等の材料に対して、その金属組織が微細化しているか否かを簡単な構成で素早く検査できる高マンガン鋳鋼の非破壊検査方法を提供する。【解決手段】高マンガン鋳鋼の非破壊検査方法は、超音波送信工程と、超音波受信工程と、微細化判定工程と、を含む。超音波送信工程では、検査対象となる前記高マンガン鋳鋼の表面である第１面から、当該高マンガン鋳鋼の金属組織を挟んで前記第１面と反対側に位置する表面である第２面に向かって、当該高マンガン鋳鋼の内部に超音波を送信する。超音波受信工程では、前記超音波送信工程で送信された前記超音波、又は当該超音波が反射した反射波を受信する。微細化判定工程では、前記超音波受信工程で受信した波のうち、直接受信した前記超音波の大きさ、又は、前記第２面で反射した反射波の大きさに基づいて、前記高マンガン鋳鋼の前記金属組織が微細化しているか否かを判定する。【選択図】図３