对750℃不同热处理时间2205双相不锈钢析出相的定性定量分析
来源期刊：冶金分析2010年第9期
论文作者：缪乐德 张毅 王国栋 王治宇 邬君飞
文章页码：6 - 13
关键词：双相不锈钢； 金属间相； 热处理； 定性定量分析
Key words：duplex stainless steel； inter-metallic phases； isothermal treatment； qualitative and quantitative analysis
摘 要：经过等温热处理,双相不锈钢中铁素体在向奥氏体转变的过程中通常会形成碳化物相、金属间相、氮化物析出相等。这些析出相在合金中形成将导致不锈钢的脆化,显著降低钢的塑性、韧性和耐蚀性。为了对750℃不同热处理时间双相不锈钢析出相做定性定量分析,本实验首先研究了不同电解体系下双相不锈钢的电解效果,在选择好合适的电解液后,利用电解分离方法将析出相从基体中分离。通过扫描电镜(SEM)和X射线衍射(XRD)定性研究了提取后析出相的形貌以及结构特性的变化过程;此外,利用氧氮分析仪测定了析出相的氮含量;利用碳硫分析仪测定了残渣经酸处理后的碳含量。最后,通过电感耦合等离子体发射光谱(ICP-AES)检测化学分离后溶液中合金元素的含量,并结合氮和碳含量的数据,计算不同析出相的元素组成及含量,最后讨论了750℃下不同热处理时间对析出相的影响,在时效开始时先形成金属间相χ相,随着时间的延长,χ相减少,而σ相逐渐形成并最终占主量。
Abstract: After isothermal heat treatment,carbide phase,intermetallic phase and nitride precipitated phase were generally formed during the transformation process from ferrite to austenite in duplex stainless steel.These precipitated phases in alloy would cause the embrittlement of stainless steel,the remarkable decrease of plasticity,ductility and corrosion resistance of steel.For the qualitative and quantitative analysis of precipitated phase of 2205 duplex phase stainless steel with different heat treatment time at 750 ℃,the electrolysis results of duplex stainless steel with different electrolysis systems were firstly studied.After selecting proper electrolyte,the precipitated phase was separated from the matrix by electrolysis separation.The topography and structural change process of precipitated phase after extraction were qualitatively investigated by scanning electron microscope (SEM) and X-ray diffraction(XRD).Moreover,the content of nitrogen in precipitated phase was measured by oxygen-nitrogen analyzer.The content of carbon in residue after acid treatment was analyzed by carbon-sulfur determinator.The content of alloy elements in solution after chemical separation was tested by inductively coupled plasma-mass spectrometry (ICP-AES).By combining the content of nitrogen and carbon,the elemental composition and content of different precipitated phases were calculated.Finally,the effect of heat treatment time on the precipitated phase at 750 ℃ was discussed.The intermetallic phase χ phase firstly formed during the beginning of aging.χ phase decreased with the prolonging of heat treatment time,while σ phase gradually formed and finally predominated the precipitated phases.
