一、前言最近新建设的火力发电厂中,其蒸汽效率在相继提高。即从本世纪六十年代末期以来的二十多年中,簇汽的温度已从保持多年的538℃上升到了566℃或593℃,蒸汽的压力也从24MPa 提高到了31MPa,超越了临界压。蒸汽条件的改善,大大促进了在以往耐热钢基础上进行的新型耐热钢的研制开发。 I. Introduction Recently, the newly built thermal power plants have successively raised their steam efficiency. In the twenty years since the end of 1960s, the temperature of cluster steam has risen from 538 ℃ which kept for many years to 566 ℃ or 593 ℃ and the pressure of steam has also increased from 24MPa to 31MPa, exceeding the critical pressure. The improvement of steam conditions has greatly promoted the development of new heat-resisting steel based on the previous heat-resisting steel.