P92钢焊接接头的高温抗氧化性研究

P92钢因优异的综合性能逐渐成为超超临界机组过热器、再热器等零部件的理想用钢,材料经焊接后,焊接接头在服役温度中的高温抗氧化性直接影响零部件的使用寿命。利用增重法研究P92钢焊接接头在650℃高温空气介质中的氧化动力学,采用OM、SEM观察和分析氧化层表面及截面形貌,利用XRD分析氧化物物相。结果表明:在一定温度下,P92钢焊接接头各区域氧化速率均是先增加后降低,然后趋于稳定值,符合抛物线规律;在650℃空气介质中氧化132 h后,焊接接头中距焊缝3 mm热影响区A部位、焊缝、母材各区域氧化层的厚度分别为45μm,30μm,27μm;焊接接头氧化后表面的主要氧化产物为Fe_2O_3。

Study on high temperature oxidation resistance properties of P92 steel welding joints

P92 steel has gradually become the ideal steel for super-heater,re-heater and other parts of super supercritical unit because of its excellent comprehensive properties.On the work condition,the high temperature oxidation resistance property of welding joints by welding affects direcdy the life of parts.In this thesis,oxidation kinetics curves of P92 steel welding joint were studied by weight gain method when the air medium temperature was 650 ℃.By OM and SEM,the oxidation products pattern on surface and section cross were observed and analyzed,through XRD,the phase was investigated.The results shows that:at a certain temperature,the oxidation rate of the welded joint of P92 steel increases first and then decreases,and then tends to the stable value,which is in line with the parabolic law;oxidizing after 132 h at 650 ℃,oxidation film thickness of A zone,welded joints,base metal at welding joints is respectively 45 μm,30 μm,27 μm;surface oxidation products of P92 steel welding joints at 650 ℃ is mainly Fe2O3.