铸造低碳马氏体不锈钢中奥氏体含量的X射线衍射定量分析

Quantitative Analysis of Austenite Content in Cast Low Carbon Martensitic Stainless Steel by X-Ray Diffraction

晶粒细小的逆变奥氏体是铸造低碳马氏体不锈钢中的常见组织,其含量与钢的力学性能密切相关。晶粒的择优取向导致α-γ双相组织中奥氏体体积分数现有的计算方法误差较大。在现有的研究基础上,通过引入取向几率密度,提出了一种简易的、用于具有明显择优取向α-γ双相组织的奥氏体体积分数计算方法,同时补充了Cu靶对应强度因子的计算。通过在ZG0Cr13Ni5Mo水轮机导叶铸件中进行取样测试,其X射线衍射图谱中可标定出α相的{110}、{200}和{211}衍射峰和γ相的{111}衍射峰。按照本方法计算得到的奥氏体体积分数为0.56%;利用传统计算方法得到的体积分数为0和1.91%;EBSD测试结果表明γ相具有{111}择优取向,含量约为0.4%。对比结果表明,本研究提出的计算方法具有较高可信度。

The reversed austenite with fine grains is a common structure in cast low carbon martensitic stainless steel,and its content is closely related to the mechanical properties of the steel.The preferred orientation of the grains leads to a large error in the calculation of the volume fraction of austenite in theα-βdual phase structure.A simple method for calculating the volume fraction of austenite with obvious preferred orientation in aα-βdual-phase structure is developed by introducing the orientation probability,and the intensity factor for Cu-Kαis supplemented.The sampling from the ZG0 Cr13 Ni5 Mo turbine wicket gate casting and testing results show that,in the X-ray diffraction patterns,the{110},{200}and{211}diffraction peaks ofαphases and the{111}diffraction peaks of y phases can be calibrated.The volume fraction of austenite is 0.56%by using the method this paper described,and the volume fractions obtained by traditional methods are 0 and 1.91%respectively.The EBSD test results show that the y phase has{111}preferred orientation,and the content is about 0.4%.The comparison results show that the method proposed in this paper has high reliability.