共查询到20条相似文献,搜索用时 187 毫秒
1.
《理化检验(物理分册)》2017,(4)
对某井特殊螺纹接头油管脱扣事故进行了深入调查研究,对失效油管试样进行了宏观分析、几何尺寸测量、金相分析、力学性能试验和化学成分分析;对油管在井下的受力状态进行了分析,对油管脱扣和接箍开裂的先后顺序进行了推断。结果表明:油管接箍脆性开裂导致了油管脱扣事故,油管接箍开裂主要与其材料屈服强度、硬度偏高以及修井过程中油管所受的温度载荷有关。 相似文献
2.
某井在试油酸化压裂过程中发生了一起油管双公短节断裂事故.对双公短节断裂事故进行了深入调查研究,并对断裂的双公短节和同批未用的双公短节取样,对断口形貌、螺纹参数、几何尺寸、力学性能、显微组织和化学成分等进行了全面试验分析.对双公短节的受力状态进行了分析计算,最终弄清了断裂原因. 相似文献
3.
张辉 《理化检验(物理分册)》2018,(6)
某油井生产11个月后发生油管短节断裂失效事故。通过对失效油管短节的宏观和微观形貌观察、显微组织分析、力学性能测试、化学成分分析,查明了其断裂失效原因。结果表明:该油管短节断裂主要是由于在油井生产工况下,油管内壁发生了多裂纹源的应力腐蚀开裂,然后在腐蚀和机械载荷的共同作用下,裂纹不断扩展并相互连接,当裂纹穿透管壁后表现为腐蚀疲劳开裂,最终导致油管短节断裂失效;油管短节加工工艺不当,提高了其断裂失效的概率。 相似文献
4.
5.
《理化检验(物理分册)》2016,(3)
某井在油管提升过程中,发现位于紧接油管挂下端的88.90mm×6.45mm油管短节发生断裂。通过宏观检验、化学成分分析、力学性能检测、显微组织分析、宏观和微观断口分析,对该油管短节的断裂原因进行了分析。结果表明:该油管短节为过载断裂,断裂的原因是油管短节外螺纹端的设计拉伸余量偏低,同时螺纹加工存在偏心,使油管短节的承载能力有一定程度的下降。 相似文献
6.
7.
《理化检验(物理分册)》2015,(4)
对某井超级13Cr钢特殊螺纹接头油管接箍横向开裂事故进行了调查研究,对开裂油管接箍和未开裂油管取样进行了裂纹宏观分析、断口微观分析、化学成分分析、金相分析和力学性能试验。结果表明:接箍横向开裂导致油管特殊螺纹接头金属对金属密封结构失效,油管里的高压气体通过金属密封位置和接箍横向开裂位置发生泄漏;而油管接箍横向开裂与其存在原始裂纹和材料屈服强度偏高有关。 相似文献
8.
《理化检验(物理分册)》2015,(4)
P110钢级油管应用于某井的试油作业过程中,短时间内发生了大量的接箍纵向开裂失效。通过宏微观分析、化学成分分析、力学性能试验、金相检验以及腐蚀产物分析等方法分析了该接箍开裂的原因。结果表明:开裂起源于接箍外表面,系油管材料在井筒内硝酸盐介质作用下于承受周向拉应力最大的接箍外表面处发生应力腐蚀开裂。 相似文献
9.
在某油田下井作业时,一支N80-1钢加厚油管在加厚部位突然断裂。通过几何尺寸测量、宏观分析、力学性能试验、扫描电镜及能谱分析等方法,分析了该油管加厚部位断裂的原因。结果表明:油管加厚部位断裂为低应力脆断,主要原因是管坯铸造缺陷改变了油管内部应力状态和应力分布;加厚油管的拉伸性能和管体外径均不满足标准要求、加厚部位壁厚不均、管体轧疤缺陷和环状凹面是该加厚油管断裂的次要原因;在主、次要原因的共同作用下,使得油管在远低于额定最小破断拉力的重力作用下发生脆性断裂。 相似文献
10.
11.
12.
《Engineering Failure Analysis》2007,14(4):606-613
A fracture accident occurred with a 244.5 mm–350 ton casing elevator and a traveling hook during casing running down. This paper gives an investigation of this accident, and analyzes the causes based on fracture surface examination and material tests. Some simulation tests are performed in order to validate the fracture mechanism. It is concluded that the casing elevator fracture originated from quenching cracks caused by surface carburization. Calculations of the fracture load acting on the casing elevator showed that the casing elevator broke first, resulting in hook fracture. 相似文献
13.
某新建小区住宅楼给水管道发生断裂.采用宏、微观检验、材质化学成分分析、力学性能比较及扫描电镜、能谱仪测定等方法对断裂件进行分析.结果表明,因用材错误,在水介质作用下,金属发生晶界腐蚀及显微组织变化,最终引起性能恶化而断裂失效. 相似文献
14.
K. Wolf 《Journal of Failure Analysis and Prevention》2002,2(3):51-56
After a quick-release fitting of an ejection seat broke, an investigation was performed to determine the manner and cause
of crack propagation. Most fractography-based investigations aim to characterize only qualitative characteristics, such as
the fracture orientation and origin position, topology, and details of interactions with microstructural features. The aim
of this investigation was to use quantitative fractography as a tool to extract information, including striation spacing and
size of the stretched zone, in order to make a direct correlation with fracture mechanic concepts.
As the crack propagated, striations were created on the fracture surface as a result of service-induced load changes. The
size of the striations were measured to estimate crack propagation rate. Remaining lifetime estimates were also made. The
dimensions of plastically stretched zones found at the tips of the cracks were evaluated using electron micrograph stereo
image pairs to characterize local fracture toughness.
To complete the failure analysis, nondestructive evaluation, metallographic examination, and chemical investigations were
carried out. No secondary cracks could be found. Most of the broken parts showed that the microstructure, the hardness, and
the chemical composition of the Al-alloy were within the specification, but some of the cracked parts were manufactured using
a different material than that specified. 相似文献
15.
The coupling of the pre-stressed thermal insulated tubing string broke down inside the steam flooding wells, after the tubing were used in high temperature and high pressure steam for about two years. With further check, it was found that most of the weld joints between the inner and outer tubing also cracked. The failure analysis for the accidents has been carried out by the analysis of chemical composition for the steels, microstructure observation, mechanical property tests, and the investigation of the service environment etc.. The results show that the early damage of the pre-stressed thermal insulated tubing string is mainly induced by the caustic stress corrosion, which can be strengthened by an unstable microstructure of the coupling serviced at high temperature for a long time. Moreover, the high pre-stress design on the thermal insulated pipe for the cyclic steam injection may be not suitable to the situation of steam flooding, which would result in the weld joint cracking. 相似文献
16.
采用宏观分析、化学成分分析、力学性能测试、金相检验及扫描电镜断口分析等手段,对某油田一根规格为φ88.9mm×6.45mm的110钢级超级13Cr马氏体不锈钢油管的刺穿失效原因进行了分析。结果表明:油管失效的实质是油管发生了氯离子应力腐蚀开裂,裂纹起源于外壁腐蚀坑底部,从外壁向内壁扩展,直到穿透壁厚,形成刺穿通道,高压流体从内向外刺出并在随后的过程中形成了刺穿孔洞。 相似文献
17.
通过理化性能检验以及扫描电镜和能谱分析等方法对某井P110EU断裂油管进行了分析。结果表明:该油管断裂属于硫化物应力腐蚀断裂;油管外壁的机械损伤是油管断裂的起源,油管硬度较高以及硫酸盐还原茵等的存在是导致该油管最终断裂失效的主要原因。 相似文献
18.
19.
采用连续驱动摩擦焊技术焊接纯铝1060/Q235低碳钢异质接头,开展两个周期(30天/60天)热电耦合实验(静载392 N+高温300 ℃+直流60 A),研究热电耦合对铝/钢异质接头焊缝微观组织、力学性能及界面生长的影响。结果表明:原始态接头界面径向金属间化合物(IMCs)层厚度不均匀,中心区域无明显IMCs生成。热电耦合30天后界面中心生成宽度为0.3~0.5 μm且以颗粒状由钢侧向铝侧弥散分布的IMCs层,整体拉伸断裂在铝母材的热力影响区。热电耦合60天后IMCs层与钢侧之间出现腐蚀沟槽,IMCs破碎,钢侧无裂纹产生,铝侧形成大量由IMCs层向铝母材内部扩展的裂纹和孔洞,焊缝及裂纹尖端处成分偏析,整体拉伸断裂在焊缝处。界面腐蚀和失效速率与界面IMCs层的厚度成正比,即vcenter<v1/2R<v2/3R。由于原始态接头界面组织不均匀以及热电耦合实验过程中界面不同位置组织生长速率的差异,使得热电耦合后接头界面2/3R位置出现不同断裂形貌的分界线,2/3R内侧以准解理断裂方式为主,2/3R外侧为韧窝断裂和准解理断裂的综合结果。 相似文献