Papers by Keyword: Detecting Flaws

Abstract: Three different flaws were detected in a Q345qD hot rolled steel plate by ultrasonic test. The morphologies, chemical compositions and formation causes of these flaws were studied by using metallographic examination, Electron Probe Micros-analyzer (EPMA) and Energy Dispersive X-ray Spectrometer (EDS) analysis. Besides, some corrective measures were proposed to reduce the incidence rate of these detecting flaws.

Abstract: The flaws in a heavy bridge-making steel plate (Q370qE) were detected by ultrasonic test, the types and formation reasons of which were studied by metallographic examination, scanning electron microscope (SEM) and energy dispersive X-ray (EDX) spectrometer. The results showed that the types of the flaws were mainly crack, micropore and inclusion. The formation of crack and micropore was attributed to the center segregation, porosity, as well as the role of structural stress and thermal stress. Moreover, the inclusions were mainly composite oxides (MgO, Al₂O₃, CaO, etc.) and MnS, the former came from the raw materials and impurity oxides, however, the latter came from the center segregation of the alloying elements. Besides, some improvement measures to reduce detecting flaws were also proposed.