In this work several methods including sulphur printing,modified spark spectrum analysis and SPEED-SEM-EDX methods were used to study the morphology,composition and distribution of inclusions in pipeline steel.The pro...In this work several methods including sulphur printing,modified spark spectrum analysis and SPEED-SEM-EDX methods were used to study the morphology,composition and distribution of inclusions in pipeline steel.The procedure for the last-mentioned method includes:metal sample preparation using Selective Potentiostatic Etching by Electrolytic Dissolution (SPEED) together with inclusion observation and detection using SEM-EDX equipment.The results of sulphur printing and spark spectrum analysis showed that there was a well-defined centerline containing relatively high concentrations of sulphur in the steel slab studied in this work.The results of SEM study showed that most inclusions found in the steel samples were globular in morphology,and roughly 2-5 micrometers in size.The inclusions were rich in sulphur and manganese.Some inclusions with a bright globular shape contained Al,Ca,Mn and S,and were likely composed of MnS,CaS and calcium aluminate.It was concluded that sulphur printing is a convenient and inexpensive method for inclusion analysis,Spark Spectrum Analysis provides a complete and self-contained technique for inclusion detection,and the SPEED-SEM-EDX procedure is best suited for in-situ and three-dimensional observation of inclusions.展开更多
In accordance with a fresh accident by severe expansion cracks of structural elements , based on systematic detection and analyses such as X-ray diffraction, differential thermal analysis, scanning electron mi-croscor...In accordance with a fresh accident by severe expansion cracks of structural elements , based on systematic detection and analyses such as X-ray diffraction, differential thermal analysis, scanning electron mi-croscory, chemical analysis, petrographic analysis, electronic probe analysis, and atomic absorption spectroscopy analysis, it is pointed out that the dominant reasons lie in the hydration reaction of magnesia in concrete aggregates , resulting in a volume expansion in structure members. A wholly new corresponding .strengthening method is applied to the, cracked elements and turned out to be effective.展开更多
文摘In this work several methods including sulphur printing,modified spark spectrum analysis and SPEED-SEM-EDX methods were used to study the morphology,composition and distribution of inclusions in pipeline steel.The procedure for the last-mentioned method includes:metal sample preparation using Selective Potentiostatic Etching by Electrolytic Dissolution (SPEED) together with inclusion observation and detection using SEM-EDX equipment.The results of sulphur printing and spark spectrum analysis showed that there was a well-defined centerline containing relatively high concentrations of sulphur in the steel slab studied in this work.The results of SEM study showed that most inclusions found in the steel samples were globular in morphology,and roughly 2-5 micrometers in size.The inclusions were rich in sulphur and manganese.Some inclusions with a bright globular shape contained Al,Ca,Mn and S,and were likely composed of MnS,CaS and calcium aluminate.It was concluded that sulphur printing is a convenient and inexpensive method for inclusion analysis,Spark Spectrum Analysis provides a complete and self-contained technique for inclusion detection,and the SPEED-SEM-EDX procedure is best suited for in-situ and three-dimensional observation of inclusions.
文摘In accordance with a fresh accident by severe expansion cracks of structural elements , based on systematic detection and analyses such as X-ray diffraction, differential thermal analysis, scanning electron mi-croscory, chemical analysis, petrographic analysis, electronic probe analysis, and atomic absorption spectroscopy analysis, it is pointed out that the dominant reasons lie in the hydration reaction of magnesia in concrete aggregates , resulting in a volume expansion in structure members. A wholly new corresponding .strengthening method is applied to the, cracked elements and turned out to be effective.
