Study And Manufacture Of The Large Nuclear Steam Generator Tubesheet

In order to meet the requirement of the homemade of nuclear forgings, the paper presented a study on the character of the nuclear material and properties requirement . On the basis of a lot of theories and test data , we study the chemical composition , melting process ,forging process ,heat treatment process . Under the full of prepare ,the steam generator tubesheet was manufactured. Then , the chemical composition , the room tensile test, the 350℃tensile teat ,impact test (including +20℃,0℃and -20℃), non-ductility temperature ,FATT curve ,micrographic examination(including grain size, non-metallic inclusion and Microstructure) and macrographic examination of the steam generator tubesheet forging were performed after manufacturing.The following were demonstrated from above results: (1)The content of Mn , Mo , Ni element is in upper limit and C element in medium lever, at the same time reducing impurity elements such as P , S , As , Sn and Sb. (2) In order to thin the grain size,add N ,Al element and enhance cooling speed during the preliminary heat treatment . (3)During quality heat treatment the tempered B can be obtained with the heat-treatment of water cooling and high tempering. Then, the requirements of high toughness were met and the optimum mechanical properties were gained for the steam generator tube sheet forging.