Apart from the results of the joint research projects SSG gained results for creep rupture tests for the CB2 steel for varying melt metallurgies (current arc furnace/ aod converter) and different quality heat treatments from numerous parts in production. Te results for the achieved creep rupture strength lie within or above the fluctuation margin of the samples recorded and forecasted in the joint research groups.
Te CB2 steel (GX13CrMoCoVNbNB9-2-1) is a successor of the conventional high temperature steel P91 (G-X12CrMoVNbN9-1), P911, and P92 (G-X12CrMoWVNbN10-1-1) developed in order to allow higher operating temperatures while maintaining at least the same mechanical properties. Tis can be achieved by varying the melt analysis and adding cobalt and boron to the given alloy. Te advantages of the CB2 steel for applications in
highly critical steam conditions are obvious. Several research projects proved that the creep rupture strength of CB2 steel is higher at the same temperature and pressure than conventional high alloyed 9% chrome steel. Te operating temperatures can thus be higher without
sacrificing the mechanical properties. Moreover, the wall thickness might be reduced in order
to save a significant amount of material. A lower wall thickness will also result in a lower thermal stress. Casting Production in CB2 Steel Despite intense and long research in Europe, this new material is hardly used by power plant designers.
通过对生产的很多铸件，使用不同熔炼工艺（目前使用 的是电弧炉或氩氧脱碳转炉）和热处理效果不同的CB2 合金钢进行蠕变断裂强度检测中获得了研究成果。 CB2合金钢(GX13CrMoCoVNbNB9-2-1)是继传统 高温合金钢P91(G-X12CrMoVNbN9-1)、P911以及 P92 (G-X12CrMoWVNbN10-1-1)之后研发的新产 品。通过改变现有的熔炼分析方式、在合金中添加钴和 硼，可以使合金保持机械性能的同时，承受更高的操作 温度。 CB2合金钢在蒸汽条件要求高的情况优势非常明显。 几个研究项目已证明，在同一温度和压强下，CB2合金 钢的蠕变断裂强度比传统的钴含量为9%的高钴合金钢 更强。
因此，操作温度可以在不牺牲机械性能的同时更高。 此外，为了大大节约材料的使用，合金的壁厚可以变 薄，也可以通过较低的热应力使壁厚更薄。
CB2合金钢铸件生产
尽管CB2合金钢经历了长时间紧张的研究过程，这种 新材料在欧洲还是很少被发电厂使用。然而，中国的竞
Fig. 2. The net- efficiency of power plants using P91- steel is roughly 45.3%.
图2：使用P91号 牌合金钢电厂的净 效率约为45.3%。
December 2014
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