张英波 1steel, 2steel,邹德宁 1,王泉生 2,张晓明 2,李雨浓 1
摘要:18Cr-Al-Si铁素体耐热不锈钢作为一种结构连接件的新型材料,主要应用于超 (超 )临界火力发电领域。为steel了明确硅含量对该钢组织和性能的影响,以 18Cr-Al-Si铁素体耐热不锈钢为成分基础,施以添加 2组不同成分的硅含量,通过室温拉伸和高温氧化等试验方法,同时借助金相显微镜 (OM)、扫描电子显微镜 (SEM)和 X射线衍射仪 (XRD)等表征手段,对不同硅含量试验钢组织和性能进行了系统分析。结果表明,硅含量的增加会细化铁素体的晶粒尺寸并增加 M 23 C 6 碳化物的数量,试验钢的抗拉强度和屈服强度升高,伸长率下降,断裂方式由韧性断裂向韧-脆混合型断裂方式转变; 1.35Si试验钢氧化增重较大,因其钢中析出的 M 23 C 6 碳化物较多,减少了固溶于基体及形成氧化膜的 Cr含量,降低了其抗高温氧化性。
关键词:18Cr-Al-Si;铁素体;耐热不锈钢; Si;组织;性能;碳化物
Effect ofsilicon on microstructure and properties of ferritic heat-resistant steel
ZHANG Ying- bo 1 , 2, ZOU De- ning 1 , WANG Quan- sheng 2 , ZHANG Xiao- ming 2 , LI Yu- nong 1
Abstract:The 18Cr- Al- Si ferritic heat- resistant stainless steel as a new type of structural connection material is mainly used in the field of supercritical or ultra- supercritical thermal power generation. In order to clarify the influence of Si content on the structure and properties of this steel, based on 18Cr- Al- Si ferritic heat- resistant stainless steel, the Si content of two groups of different components is added.Through the test methods such as room temperature tensile test and high temperature oxidation test, meanwhile, with the help of metallurgical microscope(OM), scanning electron microscope (SEM) and X- ray diffractometer(XRD) and other characterization methods, the structure and properties of different Si content test steels were systematically analyzed. The results show that the increase of Si content will refine the grain size of ferrite and increase the amount of M23 C6 , the tensile strength and yield strength of the test steel will increase, and the elongation will decrease. The fracture mode will change from ductile to tough- brittle mixed mode. 1.35Si steel has greater mass gain, this is because more M23 C6 carbides are precipitated in the steel, thereby reducing the content of Cr dissolved in the matrix and forming the oxide film, and decreasing its high- temperature oxidation resistance.
Key words:18Cr- Al- Si; ferritic; heat- resistant stainless steel; Si; microstructure; property; carbide
来源:《钢铁》2021年第3期
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