随着能源需求量的持续增加，抗硫管钢已成为先进钢铁材料领域的重点发展钢种之一。现有研究表明，硫化物应力腐蚀开裂（SSC）和氢致裂纹（HIC）是引起抗硫管腐蚀破坏的主要形式，而由点状偏析引起的带状组织缺陷是导致SCC或HIC的关键因素。本项目拟结合理论计算、物理实验和数值模拟等手段分析油井管铸坯点状偏析的形成机制，建立凝固过程点状偏析形成的临界判据；通过观察热加工过程中点状偏析向带状组织的演变规律分析二者在形貌、尺寸、位置、金相组织和元素偏析率等方面的遗传关系，提出控制带状组织形成的临界参数。通过稀土变质剂细化铸坯凝固组织探讨铸态组织对点状偏析和带状组织的影响。本项目是对国内高品质特殊钢研发领域关键基础科学问题的探索性研究，相关成果可为解决抗硫管钢的共性缺陷问题提供理论和工艺指导。

With the continuous increase of the energy requirement, the development of sulfide stress corrosion cracking (SSC) resistant tube steel has been an important issue in the field of advanced steel materials. SCC and hydrogen induced crack (HIC) are regarded as the main reasons for the corrosion damage of tubes under hydrogenating environment. It is widely accepted the banded structure, resulted from the spot segregation, is the critical factor influencing this SCC or HIC behavior. In this research, with the employment of theoretical calculation, physical experiment and numerical simulation, the mechanism on the formation of spot segregation in SSC-resistant tube steel will be revealed, and the criterion for the condition under which spot segregation occurs will be proposed. The heredity of the morphology, dimension, location, metallographic structure and solute segregation ratio from spot segregation to banded structure during hot work process will be illustrated, and the critical parameters for the prevention on the occurrence of banded structure in SSC-resistant tube steel will be put forward. The dominant mechanism on SCC or HIC induced by spot segregation will be interpreted. The rare earth element will be added to the blooms of SSC-resistant tube steel to refine the solidification structure. The relationship between the solidification structure and the spot segregation will be further discussed. The proposed project is an exploratory research on key fundamental scientific issues in the development of high quality special steel. It is strongly expected that the achievement will be the theoretical basis for solving the common problem of SSC-resistant tube steel.