| In present paper low carbon steel 20g which working in power plant below the temperature 350 centigrade is researched. The regularity of change of merchant performance, microstructure and the relationship between the change and material failure during the period of material working are focused on.The specimen is obtained by collecting low carbon steel pipe experienced different time in power plant and heat treatment experiment of unused same type steel. The microstructure is analyzed by metallographies, SEM, EPMA and TEM. At the same time merchant performance is also tested.The change regularity for performance and microstructure of low carbon steel is summarized. The main characteristic of the process is pearlite spheroidizing, increasing of grain boundary width, element segregation and carbide in grain boundary. The change of those microstructure causes the variance of the merchant performance. On the basis of the regularity the failure accidents in three power plants are analyzed carefully. As the result of the research some advice on safe production for the power plant is provided, too. |
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