铁素体耐热不锈钢X10CrAlSi18组织和性能研究
发布时间：2018-07-16 09:28
【摘要】：当前能源需求旺盛,为了满足国民经济对电力的迫切需要,同时要应对来自环境保护方面的要求和挑战,势必要大力推广大容量和高参数的超(超)临界发电技术,而发电机组的关键部件之一要选用高性能锅炉管用耐热钢材料。铁素体耐热不锈钢具有成本低、热膨胀系数小、热传导率高、综合力学性能好等优点。然而,随着火力发电技术的不断发展,现有的铁素体耐热不锈钢已很难满足未来超(超)临界发电大容量和高参数的要求,人们都在尝试利用各种途径来研制新型铁素体耐热不锈钢,进而提高其使用性能。X10CrAlSi18钢是一种新型高Cr铁素体耐热不锈钢,具有较优的综合性能,已在国外投入生产,国内同种材料的应用几乎完全依赖于进口,且国内外对该钢组织和性能的研究较少,因此非常有必要对该钢进行系统地研究,以便更安全的使用。本文以工业化生产X10CrAlSi18耐热不锈钢板为研究对象,采用数值模拟计算、扫描电子显微镜(SEM)、能谱分析(EDS)、X-射线衍射分析(XRD)、拉伸试验以及冲击试验等手段,主要从热处理制度对组织和力学性能的影响以及X10CrAlSi18耐热钢的抗高温氧化行为两个方面进行深入研究。得到的主要研究结果如下:利用Thermo-Calc软件完成了热力学平衡相图的计算,可以辅助分析在不同热处理制度条件下,显微组织的变化情况。计算结果表明:X10CrAlSi18耐热钢相变过程中,基体中会有AlN相、M7C3碳化物、M23C6碳化物及Sigma相产生。为调整组织,消除内应力,提高其加工性能,特对该钢进行退火和回火处理。分析得出:在800~950℃退火时,显微组织主要由铁素体相、M23C6碳化物、Sigma相以及AlN相组成。在850℃退火时,该钢组织较为均匀,平均晶粒尺寸为48.91μm,具有最优的综合力学性能。由于铁素体不锈钢具有低温脆性,掌握其韧脆转变温度可以为实际生产和加工提供参考,因此对该钢进行韧脆转变温度试验。结果表明:X10CrAlSi18耐热不锈钢韧脆转变温度约为87℃。抗高温氧化性是评定耐热钢性能优劣的一项重要指标,本文采用恒温氧化法对该钢进行了高温氧化试验,试验温度分别为800℃、900℃和1000℃,取样时间间隔为20 h。结果表明:X10CrAlSi18耐热不锈钢氧化增重曲线符合典型的抛物线规律。在1000℃时,氧化增重量明显高于800℃和900℃时的氧化增重量。根据不锈钢的抗氧化性能评定标准,800℃与900℃条件下,X10CrAlSi18耐热不锈钢属于完全抗氧化,而在1000℃时,属于抗氧化级别钢。利用XRD、SEM以及EDS等检测手段分析了氧化膜的形貌及物相组成。分析表明:在800~1000℃氧化时,氧化膜均由MnCr2O4,SiO2,Al2O3和(Fe0.6Cr0.4)2O3氧化物构成。但在800℃和900℃,氧化膜中以尖晶石结构的MnCr2O4氧化物为主;而在1000℃氧化时,氧化膜中以尖晶石结构的(Fe0.6Cr0.4)2O3氧化物为主。这种由Cr/Mn氧化物到Fe/Cr氧化物的转变,是导致抗氧化性下降的主要原因。
[Abstract]:The current energy demand is exuberant. In order to meet the urgent needs of the national economy for electricity and to meet the requirements and challenges from the environmental protection, it is inevitable to vigorously promote the supercritical generation technology with large capacity and high parameters. One of the key components of the generator set is heat resistant steel material for high performance boiler tubes. Ferritic heat resistant stainless steel has the advantages of low cost, low thermal expansion coefficient, high thermal conductivity and good comprehensive mechanical properties. However, with the continuous development of thermal power generation technology, the existing ferrite heat-resistant stainless steel can hardly meet the requirements of large capacity and high parameters for future supercritical power generation. People are trying to develop a new type of ferrite heat-resistant stainless steel by using various ways, thus improving its performance. X10CrAlSi18 steel is a new type of high-Cr ferrite heat-resistant stainless steel, which has excellent comprehensive properties and has been put into production abroad. The application of the same material in China is almost dependent on imports, and there are few researches on the structure and properties of the steel at home and abroad, so it is very necessary to study the steel systematically in order to use it more safely. In this paper, the industrial production of X10CrAlSi18 heat-resistant stainless steel plate was studied by means of numerical simulation, scanning electron microscope (SEM), energy dispersive analysis (EDS), X-ray diffraction (XRD), tensile test and impact test. The effect of heat treatment on microstructure and mechanical properties and the oxidation resistance of X10CrAlSi18 heat-resistant steel at high temperature were studied. The main results are as follows: Thermo-Calc software was used to calculate the thermodynamic equilibrium phase diagram, which can be used to analyze the change of microstructure under different heat treatment conditions. The results show that during the phase transformation of the steel, the AlN phase M7C3 carbides, M23C6 carbides and Sigma phases can be produced in the matrix during the phase transformation of Heat-resistant Steel X10CrAlSi18. In order to adjust the microstructure, eliminate the internal stress and improve the processing property, the steel was annealed and tempered. The results show that when annealed at 800 鈩，
本文编号：2125958
[Abstract]:The current energy demand is exuberant. In order to meet the urgent needs of the national economy for electricity and to meet the requirements and challenges from the environmental protection, it is inevitable to vigorously promote the supercritical generation technology with large capacity and high parameters. One of the key components of the generator set is heat resistant steel material for high performance boiler tubes. Ferritic heat resistant stainless steel has the advantages of low cost, low thermal expansion coefficient, high thermal conductivity and good comprehensive mechanical properties. However, with the continuous development of thermal power generation technology, the existing ferrite heat-resistant stainless steel can hardly meet the requirements of large capacity and high parameters for future supercritical power generation. People are trying to develop a new type of ferrite heat-resistant stainless steel by using various ways, thus improving its performance. X10CrAlSi18 steel is a new type of high-Cr ferrite heat-resistant stainless steel, which has excellent comprehensive properties and has been put into production abroad. The application of the same material in China is almost dependent on imports, and there are few researches on the structure and properties of the steel at home and abroad, so it is very necessary to study the steel systematically in order to use it more safely. In this paper, the industrial production of X10CrAlSi18 heat-resistant stainless steel plate was studied by means of numerical simulation, scanning electron microscope (SEM), energy dispersive analysis (EDS), X-ray diffraction (XRD), tensile test and impact test. The effect of heat treatment on microstructure and mechanical properties and the oxidation resistance of X10CrAlSi18 heat-resistant steel at high temperature were studied. The main results are as follows: Thermo-Calc software was used to calculate the thermodynamic equilibrium phase diagram, which can be used to analyze the change of microstructure under different heat treatment conditions. The results show that during the phase transformation of the steel, the AlN phase M7C3 carbides, M23C6 carbides and Sigma phases can be produced in the matrix during the phase transformation of Heat-resistant Steel X10CrAlSi18. In order to adjust the microstructure, eliminate the internal stress and improve the processing property, the steel was annealed and tempered. The results show that when annealed at 800 鈩，
本文编号：2125958
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