一种大型深水海上风电导管架流水化建造工艺

海上风电项目具有建造工期短、批量大的特点,从整体结构设计及分析、分部分片预制、特殊节点及总装建造的工装设计、建造工艺方案的设计等方面进行研究,开发一套适用于大型深水海上风电导管架批量化流水化的建造工艺,该建造工艺可实现快速组对流转、流水化作业,保证焊接及建造质量,大幅缩短建造工期,降低建造作业风险,有效降低建造成本,为海上风电导管架项目的整体化、批量化、流水化建造积累了陆地建造经验。目前,该建造工艺已经在该海上风电项目中成功应用,并取得良好效果,可推广应用于大型海上风电导管架建造项目。     

埋弧横焊工艺在海上风电项目中的研究应用

为保证英国Seagreen海上风电导管架项目吸力桶和中心筒建造质量及效率,基于DNVGL-OS-C401的焊接工艺评定及焊接设计标准,结合项目的选材和-40℃时低温冲击性能的特殊要求,引入埋弧横焊焊机设备,从焊材选择、坡口设计、焊接工艺设计出发,研究开发埋弧横焊焊接工艺,并验证埋弧横焊焊接接头的焊接质量及力学性能。结果表明：埋弧横焊焊接工艺获得的完整焊接接头具有良好的强度及塑韧性,其力学性能均能满足项目规格书及DNVGL-OS-C401标准的接收准则,埋弧横焊焊接工艺可被推广应用于海上风电导管架项目。     

海洋平台用钢D36超大厚度焊接接头CTOD试验

依据英国标准BS7448断裂韧度试验标准(ISO/TC164/SC4-N400)和DNV-OS-C401,采用埋弧焊和CO2气体保护焊工艺对国产钢板板厚为80 mm的海洋石油平台导管架对接接头试样进行了低温裂纹尖端张开位移(CTOD)试验.测试了零度下该工艺的焊缝和热影响区的CTOD断裂韧度,探讨了这种大厚板焊接接头在埋弧焊和CO2气体保护焊工艺下免除焊后热处理的可能性,为海洋平台施工建造提供科学依据.     

钢箱梁焊接接头的断裂韧度评定

采用冲击试验评定钢箱梁焊接工艺存在局限性,指出用裂纹尖端张开位移(CTOD)试验评定钢箱梁焊接工艺的优越性.介绍了焊接工艺CTOD断裂韧度评定的方法.针对港深西部通道香港段后海湾大桥钢箱梁焊接建造,运用英国标准BS7448对两项拟用焊接工艺进行CTOD试验评定.结果表明,埋弧自动焊工艺焊接接头的CTOD断裂韧度较高,该工艺可以直接用于钢箱梁焊接施工;而焊条电弧焊工艺焊接接头的CTOD断裂韧度较低,经扫描电子显微镜断口分析和X射线分析,发现其原因是焊缝中心存在气泡、微裂纹、夹杂物和硫等有害元素.试验评定结果为港深西部通道香港段后海湾大桥钢箱梁焊接质量控制提供了依据.     

海洋钢结构免气刨埋弧焊焊接工艺

海洋石油平台结构中的导管架、组块和钢桩中,需要进行大量的埋弧焊焊接工作。由于绝大多数的埋弧焊均采用双面焊接,为了保证根部的焊接质量,一般都需要进行碳弧气刨清根,这不仅增加了施工工序,也使得建造效率有所降低。为此进行工艺优化,开发免气刨焊接工艺很有意义。基于此进行的焊接试验,其最终无损检测和破坏性试验结果表明,其焊接质量满足相关标准要求,该工艺开发获得成功,并在我国某导管架项目上进行了应用,取得了良好的经济效益和社会效益,对以后大型深水海洋工程结构的制管作业具有很好的指导意义。     

海上风电导管架用钢管的JCOE加工制造与性能评定

基于某海上风电导管架项目的建造要求,所选用结构钢材分别为EN10025-3 S355N/NL和EN10025-4 S355M/ML,须满足-40℃下最小冲击吸收能量34 J的低温韧性要求,焊接工艺评定及建造须符合DNVGL-OS-C401—2018和DNVGL-ST-0126—2018要求。文中基于高效JCOE管道成形工艺,详细介绍了焊接母材的成分与性能、坡口设计、焊道顺序、焊接材料选择和焊接工艺参数,观察焊接接头宏观形貌,并对焊接接头进行拉伸、弯曲、-40℃低温冲击吸收能量和硬度试验。分析和测试结果表明,薄壁管和厚壁管的焊缝成形都非常优良,且各项力学性能均满足该项目规格书及相关标准的技术要求。该工艺方案具有生产效率高,焊接质量稳定的优点,适合于除海上风电导管架用钢管之外的其它管材的加工制造,具有广阔的推广价值和应用前景。     

TMCP钢表面堆焊工艺研究

依托公司承接的导管架平台建造项目进行了研究,此项目母材全部采用欧标EN 10225 S355类TMCP供货钢。文中基于欧标TMCP钢焊接特点,主要研究了EN 10225 S355 TMCP钢表面堆焊工艺特点,成功地研发了大间隙焊接工艺,并对焊接接头进行了性能测试,完全满足业主和规格书的要求,给其他类似项目提供了借鉴。     

导管架裙桩套筒的装配及焊接

裙桩式导管架结构平台在我国东海及南海海域应用广泛。裙桩套筒的结构复杂,焊缝数量多,焊接工作量大,焊接变形控制及焊接质量控制存在很大难度。东海某导管架陆地建造中,从装配顺序、焊接变形以及焊接工艺等方面严加控制,在尺寸精度及焊接质量方面均取得良好效果。     

深水导管架的焊接质量控制

全世界海洋石油工业高速发展,作为海洋石油工程结构物的深水导管架相较于陆地钢结构,具有服役环境更加恶劣、钢材强度更高、结构形式更为复杂的特点,对焊接质量的要求也更为严苛。以东海某导管架为建造实例,深入探讨深水导管架的焊接质量控制。     

海洋石油工程固定式导管架平台TKY节点的焊接

导管架作为海洋石油工程固定式平台的支撑结构物,是由钢管相贯焊接而成的空间桁架结构,其中TKY节点是其最主要的焊接结构,其焊接质量直接决定了固定式平台的安全性和使用性。文中以东海某固定式导管架平台为例,重点从该平台建造中TKY节点的焊接工艺设计、TKY节点焊接作业所需焊工资质要求、TKY节点制备的注意事项、TKY节点的焊接质量控制和TKY节点的焊接裂纹返修等方面进行讨论。     

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。