码头钢管桩防腐工艺选择

为降低码头钢管桩在海洋环境下的腐蚀速率,延长使用寿命,结合海洋环境腐蚀的机理,分析了码头钢管桩腐蚀的原因及腐蚀特点。通过分析筛选得出:在阴极保护方法中,牺牲阳极保护法相比强制电流保护法,投入小、稳定性好,更适用于码头钢管桩阴极保护;在外防腐层方面,涂层防腐由于施工复杂、成本高不适用码头钢管桩防腐,而采用包覆改性聚乙烯防腐带的方法具有施工简单,投入小,防腐效果好的特点。所以,采用牺牲阳极保护与包覆改性聚乙烯防腐带联合防腐法比较适合码头钢管桩的防腐。     

世界钢管市场

<正> 1979年世界钢管的产量是1960年的2.7倍,超过了6,000万吨。为生产钢管,1960年耗费了世界钢产量的6.4％,而1970年为8％。对耐酸、耐蚀及塑料涂层管的需求和生产在逐步增加。美国生产内外涂有环氧树脂的管子,西德采用塑料涂层防腐     

水溶性涂料在钢管防腐方面的应用

l前言钢管在储存和运输等方面都存在防腐问题。对短期储存的钢管，防腐问题不明显；而对外贸出口的钢管，因运输周期较长，海上环境恶劣，若不将钢管表面作防腐涂层处理，外表面将出现大面积锈蚀，严重影响钢管的表面质量。目前，国内有些厂家仍采用油溶性漆。但油溶性漆毒性大，操作环境恶劣，易燃，给环保带来许多麻烦，因而采用水性防腐涂料是钢管防腐的发展趋势。近几年来，天津钢管公司、宝鸡石油钢管厂、上海中轻石油钢管有限公司等大型钢管企业采用水性防腐涂料，防腐效果较好。2水溶性透明漆的特点水溶性透明漆是90年代开发成功的防…     

螺旋焊缝钢管3PE防腐层厚度分析及控制策略

现阶段的石油工程建设,必须在钢管的防腐策略上不断的完善,螺旋焊缝钢管3PE防腐层厚度的分析、控制,要结合项目的特点、要求来完善,坚持在厚度的调整过程中保持高度的灵活性,对防腐的体系、防腐的功能不断创新.     

钢管表面酸洗工艺在防腐施工中的应用分析

在油气管道防腐施工中,钢管表面处理是至关重要的一项工作,因为这一工序对钢管表面防腐涂层性能影响重大。本文以提高钢管表面处理质量为目的,基于酸洗工艺,对钢管表面酸洗工艺在油气管道防腐施工中的应用进行了分析,以保证钢管表面的防腐性能。     

钢管道聚氨酯防腐保温新一步法成型工艺技术

该技术是把绝热层和防腐层同时包覆在钢管道外表面上，从而形成管线的保温防腐层。与其它方法相比，具有连续作业、生产效率高、成本低、节约能源、无污染环境等突出优点。     

钢管的表面处理方法

长输油气管线是能源保障的重要方式,在输油（气）管线防腐施工过程中,钢管表面处理是决定管线防腐使用寿命的关键因素之一,它是防腐层与钢管能否牢固结合的前提。经研究机构验证,防腐层的寿命除取决于涂层种类、涂覆质量和施工环境等因素,钢管的表面处理对防腐层寿命的影响约占50％,     

钢管冷带热熔三层PE成型技术

冷带热熔技术是采用预制冷复合胶带缠绕在加热的钢管表面,通过加热钢管本体的热传导,熔融中间粘接剂带和聚乙烯胶带,包裹在钢管表面,与已经喷涂成型的环氧粉末形成三层PE防腐涂层.此项技术现场施工优势突出,适用于大口径的钢质弯管.     

钢管3PE外防腐层的生产技术和质量控制

随着社会的不断发展,钢管3PE外防腐层生产逐渐得到了人们的广泛关注。传统的设计方式中存在着一些弊端,主要表现为涂层间的处理不得当、生产工序混乱、漏点检测不及时等等。针对以上问题,工作人员应该对原材料的质量进行控制,把握钢管外防腐层钢管的每一道生产工序,检验产品性质。因此,本文以钢管3PE外防腐层的生产技术作为切入点,对质量控制措施进行讨论。     

凌钢集团锦西钢管有限责任公司

凌钢集团锦西钢管有限责任公司（原锦西钢管厂）建于１９５２年，是国内最早从事焊接钢管研制生产的国有大型企业，现有职工２３００人，工程技术人员２２０人。建厂４０余年来，公司已形成年产５０万t管，资产总值３亿元的经营规模，并在技术装备、产品结构、质量控制和应用开发诸方面确立了行业领先的综合优势。公司现有６套直缝焊管机组，并配有螺旋缝焊管机组、带钢纵剪机组、热浸镀锌机组、防腐机组等设备，可生产Φ２１．３～５０８mm高频直缝电阻焊钢管、Φ２１９～１６２０mm双面埋弧螺旋缝钢管、Φ２１．３～２７３mm热浸镀锌钢管…     

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.     

Thermodynamics Study on the Decomposition of Chromite with KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

Influence of Heat Treatment on Damping Behaviour of the Magnesium Wrought Alloy AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

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.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.     

电化学噪声数据处理方法概述

综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。