电站锅炉用耐热材料P92热变形行为及组织研究

Hot Deformation Behavior and Microstructure of Heat-resistant Material P92 in Power Station Boiler

对P92钢的热拉伸行为、热压缩变形行为、低倍、显微组织以及常温力学性能进行了分析研究。结果表明：当变形温度为950~1150℃时,P92可获得良好的热塑性,有力于材料的热塑性变形;在同一应变速率条件下,变形抗力对变形温度较敏感,采用较高的变形温度,可降低锻造过程中的变形抗力;当变形温度达到1050℃以上,随变形程度增加,会发生奥氏体组织的动态再结晶,从而进一步细化晶粒。变形抗力随变形温度的升高显著降低,因此在不发生过热的情况下,应采用尽可能高的变形温度,以降低锻造过程中的变形抗力。综合考虑各种因素,选定的较佳锻造温度为950~1150℃;采用真空熔炼＋锻造工艺开可生产组织致密、晶粒细小、探伤缺陷当量小的P92管坯,经检验,各项常规性能满足国标和美标要求。

The hot tensile behavior, hot compression deformation behavior, low magnification, microstructure and mechanical properties of P92 steel were analyzed. The results show that： when the deformation temperature is 950-1150 ℃,the good thermoplastic of P92 could be gained, which is good to the hot deformation of the material. Under the condition of the same strain rate, the deformation resistance is more sensitive to deformation temperature.The high deformation temperature could reduce the deformation resistance during forging process; when the deformation temperature is above1050 ℃, austenite generates dynamic recrystallization with the degree of deformation increasing, the grains were further refined. The deformation resistance significantly reduces with the deformation temperature increasing, so in case of overheating not occuring. A high deformation temperature should be used in order to reduce the deformation resistance of the forging process, considering a variety of factors, a preferred forging temperature of 950-1150 ℃ is selected. The P92 pipe billets with fine grain sizes, small defect detection equivalent and dense microstructures could be produced by vacuum induction melting process and forging process. The routine performance could meet the requirements of national standard and American standard in the test.