ZG40Cr25Ni20炉管服役后断裂韧性试验分析及断口微观形貌研究

将断裂力学原理应用到炉管寿命预测中.利用MTS810试验机,对服役3万h的炉管和未服役炉管的断裂韧性进行了试验分析,并利用扫描电镜进行了断口的形貌分析.研究结果表明:服役后炉管的断裂韧性与未服役炉管相比显著下降,抵抗裂纹扩展能力减弱;服役后的炉管断裂面没有裂纹稳态扩展区和宏观塑形变形,对应于断裂韧性的下降,断裂面微观形貌呈典型的脆性断裂特征.     

加热炉炉管爆裂原因分析

调查了规格为φ127mm×9mm的20钢加热炉炉管发生爆裂的事故,通过化学成分分析、力学性能检测、金相分析及扫描电镜分析等方法对炉管爆裂原因进行了分析.结果表明:炉管爆裂失效为炉管表面的折叠缺陷所致;炉管穿孔成形时产生的折叠缺陷使炉管表面形成应力集中,减小了炉管的有效承压壁厚.     

一段转化炉炉管焊接工艺

一段转化炉(101B)是年产30万t合成氨装置的关键设备.炉管工作压力高达3.5 MPa,温度920℃,处理介质为富氢气体.炉管中转化管材质为HP50、下集气管材质为Incoloy800,均系奥氏体耐热钢.为了保证炉管更换的焊接质量,根据现场条件和烽接质量的要求,对转化管和下集气管材质的化学成分和力学性能进行分析,选用合适的焊接方法和焊接材料以及相应的焊接工艺参数,进行了焊接工艺评定试验和现场焊接,成功地将进口转化炉管更换为国产炉管.从1999年以表,所更换的国产转化管在运行过程中,尚朱因炉管的焊接质量而发生问题.证明更换转化管的焊接工艺合理,切实可行.     

TP304H服役炉管的组织变化研究及寿命预测

研究了TP304H奥氏体不锈钢新炉管中服役2、3万小时的炉管试样组织.结果显示,已服役炉管在设计温度650℃下运行2、3万小时后的组织和形貌已发生变化,产生析出相,沿内壁还出现大量黑洞,部分地方还有氧化物.研究认为高温是影响析出相的主要因素.室温拉伸试验结果显示,随着服役时间的延长,炉管材质发生了一定程度的脆化.最后通过高温持久试验,采用L-M参数法预测了炉管的剩余寿命.     

油田注汽锅炉炉管爆裂失效分析

为了弄清某油田注汽锅炉炉管爆裂的原因,分别对爆裂炉管的材质、爆裂炉管及其断口处的宏观形貌、显微组织及注汽锅炉水质等方面进行了全面检验,经分析得出注汽锅炉炉管爆裂是由于超温过载引起的.     

Cr9Mo炉管高温服役后性能测试及弯曲原因分析

通过宏观观察、硬度测试、金相分析、常温和高温拉伸试验、冲击试验和扫描电镜等方法,对高温服役后的Cr9Mo炉管进行性能测试,并分析弯曲原因.结果表明:炉管金相组织明显球化;常温下的伸长率,硬度和冲击性能有所下降,高温下的屈服强度和抗拉强度均比规范值低;热应力导致炉管弯曲.     

焊接残余应力对焊接接头蠕变性能的影响

应用大型有限元分析软件ABAQUS及其RESTART功能,建立了焊接温度场模型、残余应力场模型和蠕变分析模型.使用焊接残余应力作用下蠕变的顺次耦合有限元计算方法,对Cr5Mo加热炉炉管焊接接头残余应力和蠕变进行了数值模拟.计算方法为掌握复杂的焊接残余应力对高温炉管焊接接头的蠕变影响奠定了基础.比较了考虑焊接残余应力和仅承受内压两种工况下的炉管接头蠕变情况.结果表明,虽然焊接残余应力在短时间内松弛,但焊接残余应力决定了炉管的蠕变变形,焊接残余应力是影响炉管蠕变的重要因素.     

油田注汽锅炉炉管爆裂断口的金相分析

注汽锅炉是油田开采的重要设备,但不断出现炉管爆裂事故.为了找出原因,通过分析爆破炉管的成分、宏观形貌及显微组织,得出注汽锅炉炉管产牛爆管的主要原因是炉管壁温超温所致.     

乙烯6号炉预热段翅片管腐蚀泄漏原因分析

对发生腐蚀穿孔的乙烯6＃炉预热段翅片管腐蚀穿孔的原因进行了分析,通过对腐蚀产物的能谱分析和金相组织分析,指出烧焦时烧焦空气窜入,引发FeS反复氧化燃烧剥落所致.是造成翅片管均匀腐蚀的主要原因.由于预热段炉管为水平安装,在裂解炉停工蒸汽吹扫过程中,残留的蒸汽冷凝成水汇集在炉管下部或凹陷处,进入炉内空气中的氧溶解在其中,从而形成了氧的腐蚀环境,使炉管因腐蚀形成的FeS保护膜遭到破坏,最终导致炉管下部穿孔.     

裂解炉对流段炉管爆裂分析

针对辽阳石化分公司烯烃厂F108裂解炉对流段炉管爆裂破坏进行了分析.结果表明，爆裂原因是由于炉管在高温下长期运行，管壁氧化腐蚀减薄并影响传热，同时管壁金相组织发生变化，使得炉管强度降低所致.     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

The Mirror with Patterns of Auspicious Animals and Grapes——Exquisite cast mirror and the technology of surface tin-enrichment by rubbing-in and infiltration of tin-rich powder

<正>Bronze mirrors were used by the Chinese people before the introduction of the glass mirror.Only after it was replaced by the glass mirror did the bronze mirror gradually retreat from people's lives.Different styles of bronze mirrors were made in different historical periods,particularly in the Warring States Period,the Han and Tang Dynasties,which were the three peaks of the development of bronze mirror arts in ancient China.The casting techniques were exquisite.The surface of the bronze mirror was smooth and bright enough to reflect one's image,and there were scarcely any casting defects on the mirror surface.On the back of the bronze mirror,there were rich depictions of Arts and Humanities,and the ornamentations were also     

The 9th China International Diecasting Congress & Exhibition

The 9th China International Diecasting Congress ＆ Exhibition was held on July 22-24, 2014 at Shanghai New International Expc Centre. This exhibition was the most successful over the years, with over 6890 visitors and 155 exhibitors, and the exhibition area increased by 30% from 9,500 square meters in 2012 to 12340 square meters. Die casting enterprises from a total of 24 countries and regions, including China mainland, Chinese Taiwan and Hong Kong, South Korea, Japan, Germany, India, Thailand, Malaysia, the United States, Russia, Australia, Iran, Ukraine, Brazil, Colombia, Singapore, Austria, Canada, Croatia, France, Turkey, United Kingdom, Vietnam, attended the congress and exhibition.     

Introduction of the Fluid Control Engineering Institute of Kunming University of Science and Technology

正The Fluid Control Engineering Institute of Kunming University of Science and Technology was set up in 1996.The researches of institute concentrate on electro-hydraulic(pneumatic)servo/proportional control and hydromechatronics.The Institute is committed to research and development of electro-hydraulic control of high-end technical equipment in ferrous metallurgy refining produc-     

RARE METALS Volume Contents

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Antimony Induced Crystallization of Amorphous Silicon

Antimony induced crystallization of PVD (physics vapor deposition) amorphous silicon can be observed on sapphire substrates. Very large crystalline regions up to several tens of micrometers can be formed. The Si diffraction patterns of the area of crystallization can be observed with TEM (transmission electron microscopy). Only a few and much smaller crystals of the order of 1μm were formed when the antimony layer was deposited by MBE (molecular beam epitaxy) compared with a layer formed by thermal evaporation. The use of high vacuum is essential in order to observe any Sb induced crystallization at all. In addition it is necessary to take measures to limit the evaporation of the antimony.     

A CUMULATIVE FATIGUE DAMAGE RULE UNDER THE ALTERNATIVE OF CORROSION OR CYCLIC LOADING

Fatigue damage increases with the applied loading cycles in a cumulative manner and the material deteriorates with the corrosion time. A cumulative fatigue damage rule under the alternative of corrosion or cyclic loading was proposed. The specimens of aluminum alloy LY12-CZ soaked in corrosive liquid for different times were tested under the constant amplitude cyclic loading to obtain S-N curves. The test was carried out to verify the proposed cumulative fatigue damage rule under the different combinations among corrosion time, loading level, and the cycle numbers. It was shown that the predicted residual fatigue lives showed a good agreement with the experimental results and the proposed rule was simple and can be easily adopted.