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本文提出了在复杂多元铁基高温合金中判断σ相析出倾向的相分计算方法。对相当数量的工业合金和试验合金的验证,说明提出的方法是可靠的。进而简化处理的相分计算方法也是可行的。以15Cr/25Ni型铁基高温合金为例。提出的△N′_v=Ni-3Ti-3.5Al-1.7Si-0.9Cr-4.7计算式可以方便地根据△N′_v<0,或>0,来判断650℃长期时效时σ相的析出与否。同时,还可以应用△N′_v的值来分析σ相对合金有关性能的影响。 相分计算(PHACOMP)是一种预测合金中产生TCP相主要是σ相的方法,目前已广泛采用指导生产。镍基合金的相分计算方法已有许多研究[1-13],但铁基合金相分计算方法却研究不多,早期有一种经验公式[14],它规定不产生σ相的条件为:此公式既不准确又太定性,对于复杂的铁基合金是不能应用的。本文以15Cr-25Ni类合金为典型,结合其他含Ni量不同的铁基合金,试图找出一种适用于铁基合金的相分计算方法。研究的实验根据为650℃、1000～2000小时长期时效和700℃、3000小时长期时效的实验数据。
In this paper, we propose a phase-fraction method to determine the tendency of σ-phase precipitation in a complex multivalloyed iron-based superalloy. The verification of a considerable number of industrial alloys and test alloys shows that the proposed method is reliable. Further simplifying the calculation of the phase fraction method is also feasible. Take 15Cr / 25Ni iron-based superalloy as an example. The formula of ΔN’_v = Ni-3Ti-3.5Al-1.7Si-0.9Cr-4.7 can be conveniently used to judge the precipitation of σ phase at 650 ℃ for long-term aging according to △ N’_v <0, or> 0 no. At the same time, the value of ΔN’_v can also be used to analyze the effect of σ relative to the alloy’s performance. Phase-Computation (PHACOMP) is a method of predicting the predominantly sigma-phase of a TCP phase in an alloy and has so far been widely used as a guide to production. There have been many studies on the phase-fraction calculation of Ni-based alloys [1-13]. However, the calculation method of Fe-based alloys has not been studied much. There is an empirical formula in the early stage [14] This formula is neither accurate nor too qualitative, for complex iron-based alloys can not be applied. In this paper, typical 15Cr-25Ni alloy, combined with other iron-based alloys containing different amounts of Ni, trying to find a suitable phase-based iron-based alloy calculation method. The experiment is based on the experimental data of long-term aging at 650 ℃, 1000-2000 hours and long-term aging at 700 ℃ for 3000 hours.