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加热炉炉管在正常运行工艺条件下发生爆裂失效,利用光学显微镜、扫描电子显微镜、EDS分析等方法对爆裂炉管不同区域进行微观组织、形貌、断口以及腐蚀产物等进行分析。结果表明,炉管的化学成分符合1Cr5Mo的要求,不同区域的硬度及力学性能测试结果均满足石油裂化用无缝钢管中1Cr5Mo的要求。金相组织为贝氏体,在晶界与晶内出现珠光体分解的碳化物颗粒,晶粒粗化,贝氏体老化3~4级,爆裂启裂区断面粗糙,为正断型断口,而扩展区断面呈45°斜面,均呈韧窝特征的韧性开裂,扩展区则为撕裂型韧窝,断裂区内外壁表面裂纹内存在高温腐蚀垢物,裂纹尖端存在蠕变孔洞。
The heating furnace tube rupture failure under normal operating conditions. The microstructure, morphology, fracture and corrosion products of blast furnace tube were analyzed by optical microscope, scanning electron microscopy, EDS and other methods. The results show that the chemical composition of the tube meets the requirements of 1Cr5Mo. The hardness and mechanical properties of different regions meet the requirements of 1Cr5Mo in seamless steel tubes for petroleum cracking. Metallographic structure of bainite, pearlite decomposition in the grain boundaries and intragranular carbide particles appear, grain coarsening, bainite aging grade 3 to 4, burst rupture zone rough section for the normal fracture, While the extensional section has a 45 ° slope with ductile cracking characterized by a dimple. The tearing dimples are present in the extension zone. High temperature corrosion scale is present in the surface and outer wall cracks in the fracture zone, and creep holes exist at the crack tip.