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本文就铁素体—奥氏体型双相不锈钢00Cr18Ni5Mo3Si2组织稳定性及其对脆性的影响进行了探讨。980℃固溶处理及在450—900℃温度区间时效后产生α→γ′+X(σ)及α→α′+脱溶产物两种类型的组织转变。在450—750℃时效沿晶界发现有一种片状的Fe_3Cr_3Mo_2Si_2金属间相,在铁素体晶内有一种Fe_(2.4)Cr_(1.3)=MoSi拓扑密排相(R相),而在750—900℃时效发现x相只是一个能转变为σ相的亚稳相。本文就α-铁素体等温转变动力学曲线进行了研究。前人研究结果认为本钢脆性是由σ相造成的,本文研究结果发现在550—650℃及800—900℃不同温度区间脆性断裂特征不同,在550—650℃区间沿晶脆性断裂主要是由于沿晶规则排列的片状Fe_3Cr_3Mo_2Si_2金属间相的析出造成的,而在800—900℃区间的准解理断裂则与α相分解为块状的σ相、x相有关。
In this paper, the ferrite - austenitic duplex stainless steel 00Cr18Ni5Mo3Si2 histological stability and its impact on the brittleness were discussed. 980 ℃ solution treatment and aging at 450-900 ℃ α → γ ’+ X (σ) and α → α’ desolvated products of two types of organizational transformation. There is a flaky Fe_3Cr_3Mo_2Si_2 intermetallic phase along the grain boundary at 450-750 ℃ and a Fe 2.4 Cr 1.3 MoSi topological close phase (R phase) in the ferrite grains, while at 750 At -900 ℃, the x phase is only a metastable phase that can be transformed into σ phase. In this paper, α-ferrite isothermal transformation kinetics curves were studied. The results of previous studies suggest that the brittleness of the steel is caused by the σ phase. The results of this study show that the brittle fracture characteristics are different between 550-650 ℃ and 800-900 ℃ in different temperature ranges. The brittle fracture along the 550-650 ℃ range is mainly caused by The intergranular Fe_3Cr_3Mo_2Si_2 intergranular phase precipitates, whereas the quasi-cleavage at 800-900 ℃ is related to the α phase and the x phase.