渗碳、蠕变共同作用下HK40和HP钢乙烯裂解炉管损伤过程模拟

通过对乙烯裂解炉管典型工况的分析,建立了炉管在渗碳、蠕变共同作用下的时变应力场的计算模型,并模拟计算了HK40和HP材料炉管在1173K工况下服役时的碳浓度分布、应力分布及蠕变损伤分数。结果表明：炉管外壁开裂主要是渗碳诱发应力所致;计算得到的炉管失效方式、位置和寿命均与实际情况基本吻合;该模型可以用来计算炉管损伤程度,还可以预测任意给定工况下炉管的剩余寿命。     

乙烯裂解炉炉管渗碳损伤分析

为了解决乙烯裂解炉炉管在高温环境下工作造成的渗碳损伤问题,选用了服役时间3～7a的10根HP40裂解炉管进行解剖,采用显微组织和成分分析等手段,研究了炉管渗碳损伤和渗碳机理。结果表明：服役炉管内壁损伤程度较外壁严重;服役时间在5a以下的炉管,内壁渗层深度大于外壁,但相同深度渗层碳含量小于外壁;渗碳实际为氧化、渗碳交替发生的过程。     

乙烯工程裂解炉管立式挤压的技术可行性分析

本文针对石化行业用２５Ｃｒ－３８Ｎｉ－Ｍｏ－Ｔｉ裂解炉管的热挤压成形,进行了技术工艺可行性分析。通过分析论证,在我公司２０００ｔ多向模锻挤压机上完全可以实现立式挤压研制开发,具有较大的经济效益。     

乙烯裂解炉管的脆断分析

本文应用断裂力学对乙烯裂解炉管脆断事故进行了分析。利用EPRI的计算结果对炉管环向表面裂纹进行了计算,结果表明,在炉管存在60mm×7mm的大表面裂纹的情况下,使炉管发生失稳脆断的主要原因是水击产生的冲击和振动弯曲应力,其失稳应力为242.4MPa。用CVDA方法对其分析可知,在同样条件下,炉管的允许裂纹为22.5mm。文中还分析了裂纹的形成过程,炉管的主要隐患是管内蠕变、腐蚀形成的局部裂纹。     

钨铝合金化的改进型乙烯裂解炉管1150℃条件下的模拟渗碳行为研究

为探究钨铝合金化的改进型乙烯裂解炉管27Cr44Ni5W3Al+MA在1 150℃条件下的渗碳损伤情况,采用粒径1.5～3 mm的固体渗碳剂,针对27Cr44Ni5W3Al+MA炉管开展1 150℃条件下50,100,150,200 h的固体渗碳试验。采用C-S分析仪和OM,SEM,EDS,XRD及维氏硬度计等对渗碳前后炉管进行成分、组织及性能分析,研究炉管渗碳行为。结果表明：从铸态至渗碳200 h时,炉管内壁1 mm范围内平均碳浓度由约0.5%增长至饱和碳浓度2.2%左右;渗碳时间由50 h增至200 h,炉管内壁渗碳层厚度由800μm增至2 860μm,渗碳层由内向外依次为严重渗碳区、中度渗碳区及轻微渗碳区,其宽度分别由400μm增至1 920μm、100μm增至140μm、300μm增至800μm。从铸态至渗碳200 h,碳化物平均宽度由2.0μm增至3.5～13.0μm,面积分数由5.6%增至13.6%～34.9%;原始铸态复相碳化物外部的小块状M₂₃C₆逐渐粗化呈链块状,然后转变为岛块状M₇C₃     

BA-111乙烯裂解炉进料预热段出口管腐蚀原因分析

对发生腐蚀穿孔的某石化公司烯烃厂E－BA111乙烯裂解炉进料预热段出口管进行了宏观腐蚀形貌分析，通过对腐蚀产物的X射线衍射相成分分析，出口管材料的化学成分和金相组织分析，指出进料预热出口管腐蚀穿孔的主要原因是：裂解炉在线清焦过程中由于蒸汽吹扫不彻底，导致残存的高硫裂解原料与清焦空气及水蒸气发生反应形成硫酸而发生了露点腐蚀。     

国产乙烯裂解炉管抽样检测状况

总结了两年多来中国石化炉管质量检测检验与评估中心对乙烯裂解炉管抽样检测的状况。对国产乙烯裂解炉141根离心铸造炉管、24根炉管焊接件以及27根静态铸造管件开展了化学成分、室温拉伸性能、高温持久性能试验和低倍组织酸蚀试验,给出了当前国产离心铸造炉管行业对杂质元素含量的控制情况、国产离心铸造炉管和静态铸造管件的室温拉伸性能与高温持久寿命状况,以及柱状晶与等轴晶比例。结果表明,当前国产乙烯裂解炉管合格率在80%~90%左右,炉管焊接件和静态铸造管件的高温持久寿命基本不合格,凸显出了国产乙烯裂解炉管行业存在的严峻问题。还就离心铸造炉管和管件杂质元素、新制造炉管性能与服役炉管失效模式的关系等问题开展了讨论。     

乙烯装置裂解气分析

采用四级冷却方式获得具有代表性的乙烯装置裂解气样品,运用色谱法分析其组成,能准确获得乙烯的收率,为乙烯装置提供很好的参考数据。     

阀杆材料在硫化氢环境下抗腐蚀开裂能力的研究

阀门设计过程中阀杆选用630代替316等材料,既保证耐蚀又提高其机械性能。通过对630材料在硫化氢下抗腐蚀开裂能力进行试验研究,以确定该材料能满足使用要求。     

Assessment of the sulfide stress corrosion cracking characteristics in the multi-pass weld of the A106 Gr B steel pipe

Sulfide stress corrosion cracking (SSCC) in crude oil field environment containing hydrogen sulfide (H₂S) has been recognized as a material degradation and damage mechanism. Laboratory data and field experience have demonstrated that extremely low concentration of H₂S may be sufficient to lead to SSCC failure of susceptible materials. In some cases, sulfides may act synergistically with chlorides to produce SSCC failures. SSCC mechanism is a form of hydrogen embrittlement that occurs in high strength steels and in localized hard zones in weld of susceptible materials. In the heat-affected zones adjacent to the weld, there are often very narrow hard zones combined with regions of high residual stress that may become embrittled to such an extent by dissolved atomic hydrogen. On the basis of this understanding, SSCC tests were conducted with smooth specimens of the multi-pass welded ASTM A106 Gr B steel pipe used in the oil industries. And SSCC resistance according to the welding processes was evaluated. From the results, the weld by GTAW+FCAW showed the largest resistance against SSCC. This paper was recommended for publication in revised form by Associate Editor Chongdu Cho Gyuyoung Lee received the M.S. degree in Mechanical Engineering from Sungkyunkwan University in 2003 and 2005, respectively. Currently he is in doctorate course in Sungkyunkwan University. He is currently serving as a Reliability member of the Korean Society of Mechanical Engineers. Lee’s research interests are in the area of welding design, environmental strength of materials, and life prediction and reliability assessment of the industrial facilities.     

精密注塑制品残余应力的试验研究及其计算

注塑残余应力对精密注塑制品的力学性能和光学性能等有重要影响,是精密注塑制品质量控制的关键指标之一。为研究注塑成形过程中残余应力的发展,以丙烯腈—丁二烯—苯乙烯共聚物(Acrylonitrile butadiene styrene,ABS)塑料为研究对象,对其模内蠕变行为进行试验研究。将热弹性模型计算的收缩应变与试验测量的收缩应变之间的差值定义为制件的模内蠕变,得到注塑工艺条件对模内蠕变的影响规律。在此基础上构建计算精密注塑制品残余应力的蠕变模型。模型中的材料弹性模量可由Tait方程计算得到,粘壶系数采用反演方法计算得到。利用该模型结合薄壳有限元法对ABS平板注塑件残余应力进行计算,对计算结果进行试验验证,并与普通的松弛模型计算进行比较。计算结果表明,该模型的计算精度高于普通的松弛模型,是解决精密注塑制品残余应力预测问题的新的有效方法。     

原油加热炉对流炉管表面腐蚀原因分析

原油加热炉管道是长输管道输送原油的主要加热设备,炉管是加热炉的核心部件,关系到加热炉的安全与正常运行。通过对对流炉管表面腐蚀产物成分及产生腐蚀原因分析,提出防止炉管腐蚀的改进措施,确保加热炉的安全运行。     

黄铜换热管的腐蚀破坏及预防措施

对黄铜管换热器管束在氨渗试验过程中发生应力腐蚀，导致铜管破裂的原因进行了分析，改进了施工方案，并提出了黄铜管换热器制造过程中对管束进行耐压试验时的注意事项。     

年产百万吨乙烯装置裂解气压缩机用汽轮机的研制

针对年产百万吨乙烯装置裂解气压缩机用汽轮机的国产化问题,依托天津石化实例应用汽轮机的研制开发项目,介绍了年产百万吨乙烯装置用汽轮压缩机组国产化研制论证立项的背景和过程,结合国内首台套该用途汽轮机研制方案的确定和实施,详述了该用途汽轮机的主要技术参数、结构配置、技术特点、需遵循和执行的国际标准,以及研制过程中需要解决的关键问题、方案难点和采取的对策措施,最后简述了该汽轮机国产化研制中获得的3个创新专利成果.研究结果表明,本研究实现了该用途汽轮机的完全国产化.     

E1023蒸汽发生器管板裂纹原因分析

综述了某石化炼油厂馏分油加氢装置E1023蒸汽发生器管板裂纹的原因，对检验发现的问题和失效原因进行了分析，并结合设备运行状况提出了预防措施。     

Fretting cracking behaviour on pre-stressed aluminium alloy specimens

A new testing rig has been developed which enables fretting tests on pre-stressed specimens to be carried out. Three aluminium alloys, Al-Li 2091, Al-Cu 2024 and Al-Zn 7075, were used in the tests. The imposed amplitude D ranged from ± 10 to ± 75 μm and normal load F_n from 500 to 1000 N. The static external stress σ_S was set as σ_D/10, σ_D/2 and σ_D (σ_D is the fatigue limit). The tests were carried out with a frequency of 1 or 5 Hz up to 10⁶ cycles. In this paper, analysis of fretting behaviour has been carried out using the fretting map concept. The effect of the axial load (pre-stress) on fretting cracking is emphasized.     

Investigation of bending creep tests. Part I: Effect of residual stress

Bending creep test (based on overhang beam geometry) is investigated by incorporating the important contribution of residual stress. Finite element simulations considering the residual stress is employed to investigate the residual stress behavior of bending creep specimen. We propose several methods to determine the creep parameters directly from the bending creep tests. We considered two cases of residual stress, one is tensile residual stress. The other is compressive residual stress. The present work may shed some light on the influences during bending creep, as well as provide an efficient way to determine material residual stress characteristics.