【作者】 费东辉；

【导师】 陈冰冰； 竺国荣；

【作者基本信息】 浙江工业大学 ， 机械工程， 2011， 硕士

【摘要】 随着石油化工行业的发展,作为大型储存容器的球罐得到大规模的使用。由于球罐缺陷的存在,对球罐的安全使用埋下了隐患,对企业的正常生产形成了巨大威胁,而对球罐的缺陷进行统计、归类和分析,就可以总结出缺陷的类型、危害以及易发生部位,对球罐的制造、使用、检验和维护等带来方便。对于球罐的缺陷统计,本文以宁波市特种设备检验研究院检验20台球罐时所发现的缺陷为样本,以列表统计、数学分析、归纳总结等方法,发现了球罐缺陷的类型、发生部位以及危害程度的一些规律,并通过理论分析、数据计算、有限元分析等方法对缺陷规律进行简单的分析。统计与分析结果表明:(1)在用球罐缺陷主要以裂纹为主,且以柱腿角焊缝裂纹、内表面裂纹和环缝裂纹为主,外表面裂纹、纵缝裂纹、极板拼缝裂纹和接管角焊缝裂纹只占很少一部分;(2)在内表面裂纹中,有应力腐蚀倾向的球罐裂纹较多,有应力腐蚀倾向球罐的裂纹平均数是无应力腐蚀倾向球罐的裂纹平均数2.4倍;(3)柱腿角焊缝裂纹、内表面裂纹和环缝裂纹以及接管角焊缝的返修率都比较高,外表面裂纹、纵缝裂纹和极板拼缝裂纹的返修率都比较低,有应力腐蚀倾向球罐的裂纹的返修率比无应力腐蚀倾向球罐的裂纹的返修率高;(4)焊接线能量低、拘束度大以及组装残余应力大是球罐环缝裂纹数量多返修率高的主要原因,应力腐蚀是导致球罐内表面裂纹数量多返修率高的主要原因,焊接质量差以及应力集中是柱腿角焊缝裂纹数量多返修率高的主要原因。更多还原

【Abstract】 The sphere tank has been widely used as one large-scale storage tank with the development of petroleum chemical industry. The risk for the safe usage of sphere tank and threats the routine production of enterprise, because of the existence of defects in the tank. To find some laws about the types, the dangers and the parts easy to occur, it is necessary to process the statistics, classification and analysis scientifically for such defects. which may be benefit to the manufacture, the usage, the inspection and the maintenance of the sphere tank.The present shows some laws about defect types, the corresponding location and the potential hazards of in-service sphere tanks by statistical method, mathematic analysis, summary and conclusion based on the sample of twenty tanks inspected by Ningbo Special Equipment Inspection Institute. And analysis of the simple rule of defects by the method of theoretical analysis, data calculation and finite element analysis, etc. It can be summed up as follows:(1)The cracks are the main defects for in-service sphere tanks,mostly occurred near the fillet welds of support leg, inner surface of the tank and girth welds, another area is unusual;(2)At Inner surface cracks ,including spherical crack of stress corrosion with the tendency, which is 2.4 times to those without the stress corrosion tendency;(3)The back repair rate is high for the fillet weld cracks of the leg, the inner surface cracks and the girth cracks as well as the nozzle fillet welds. And comparatively low for outer surface cracks, longitudinal seam cracks and butt welds of polar plate. Also the tanks with SC is higher than the tanks without SC. (4)The low heat input in welding, large intensity of restraint and assemblage induced residual stress are the main factors leading to more cracks and high back-repair rate. Stress corrosion induced cracking (SSIC) dominates the service condition of inner surface. Poor welding quality and stress concentration are two important factors controlling the crack amount and back-repair rate of the leg fillet welds.更多还原