核岛安装工程焊接工艺评定转移

焊接工艺评定转移的定义是:在符合焊接技术规格书和图纸要求的情况下(材料、人员、车间环境、失效等),焊接工艺评定由承包商的一个车间(或现场)转移到另一个车间(或现场)的活动。介绍了核岛安装工程焊接工艺评定转移的条件、焊接施工单位技术评定、技术注意事项和监督以及焊接工艺评定转移的有效期等内容。简要介绍了中国核工业第二三建设公司福清核电项目焊接工艺评定转移的流程,为以后的核岛安装工程焊接工艺评定转移提供参考。     

空冷器管束管子-管板的焊接工艺

主要从管板(厚12 mm 16MnR)和椭圆换热翅片管(基管为72 mmx20 mmx1.5 mm)焊接钢管(St37.0铜)的焊接性能、焊接工艺着手,对冷凝器管束焊接和分凝器管束焊接或缺陷补焊返修,从焊材的选择、焊接工艺、焊接效果等方面进行分析总结.     

CS-Q890钢的焊接工艺方案制订

通过对CS-Q890钢焊接性能的研究,制订了焊接工艺方案,并根据NB/T 47014—2011《承压设备焊接工艺评定》标准进行试验。焊接工艺方案是采用熔化极气体保护焊进行焊接,焊接材料选用T Union GM 120焊丝,保护气体用φ(CO_2)20%+φ(Ar)80%。研究结果表明,该焊接工艺方案符合有关标准的要求。     

钛合金线性摩擦焊工艺试验及焊接精度研究

通过TC4和TC17钛合金材料的线性摩擦焊工艺参数优化试验,获得了线性摩擦焊三个主要工艺参数(振幅、频率、焊接压力)和一个辅助控制参数(焊接缩短量)对焊接接头的焊接飞边、焊缝组织以及焊接精度的影响规律,为整体叶盘零件的工艺结构设计和工艺参数的选取提供了依据.     

通用型承压设备焊接工艺评定系统设计

结合NB/T 47014标准,针对以往相关系统开发周期长、成本高的问题和承压设备焊接工艺评定的需求,在基本的工艺文件(预焊接工艺规程、焊接工艺评定报告和焊接工艺规程)管理基础上,设计开发了通用型承压设备焊接工艺评定系统,实现了焊接工艺评定项目的辅助提出、焊接工艺评定的必要性智能判定以及焊接工艺规程的自动生成,辅助焊接工...     

焊接生产制造领域中的国际焊接标准体系及应用

以ISO 3834标准为核心的生产制造领域中的焊接标准体系,将焊接质量控制要素从9个方面的相关标准进行了归纳总结,即母材焊材、焊接工艺规程(WPS)及焊接工艺评定(WPQR)、人员资质、焊接接头检验、评定验收、焊接工艺(前、中、后)、焊材制造供应及环境、健康与安全.系统完整地归纳总结了这一体系的构成及内容,可帮助焊接专...     

9%Ni钢小角度坡口半自动氩弧焊复合工艺开发

9%Ni钢的焊接技术是LNG储罐建造项目的关键技术之一,埋弧焊(SAW)和焊条电弧焊(SMAW)是较为传统的焊接工艺。随着焊接技术的发展,半自动氩弧焊(TIPTIG)是今后9%Ni钢焊接技术的重要发展方向。本文借助TIPTIG焊接设备,成功开发了30°小角度坡口立向下与立向上组合的复合氩弧焊接工艺,与常规坡口半自动氩弧焊及焊条电弧焊相比,在保证焊接成形与焊接质量的同时,复合焊工艺节约了大量焊接材料,大大提高了焊接效率。     

焊接工艺评定的入门和实践

1　各种焊接工艺评定的共同要求国内外焊接制造规范都要求企业进行焊接工艺评定 ,以验证企业焊制符合标准接头的基本能力 (最低门槛指标 )。作为控制焊接质量最基本的方法和程序 ,ASMESectionⅨ、DNV—OS—C40 1、JB470 8、JB442 0、JB/T6963都各有阐释 ,强调在本企业工况下完成焊接评定。1.1　概　述( 1)评定目的 :“焊接工艺评定试验在于确定焊件的性能”(ASME第Ⅸ第一章QW10 0 .1) ,“在于验证焊接工艺的正确性”(JB470 8— 2 0 0 0 )。这并不是说经过焊接工艺评定的就是最佳的参数 ,而是说它合乎规范 ,可以在生产中正确应用…     

马氏体钢与奥氏体钢的焊接工艺

通过对马氏体钢和奥氏体钢各自焊接工艺特点的分析,探讨了其组合的异种钢焊接的特殊性,较详细地从焊接材料的选择、焊接工艺以及热处理方面进行了阐述。并针对电站锅炉热电偶套管(奥氏体钢)和主汽管道(马氏体钢)异种钢的焊接,提出了主要的工艺要点,认为无论选用什么样的焊接材料都必须进行预热和热处理。     

药芯焊丝电弧焊基础

药芯焊丝电弧焊(FCAW)是在焊接过程中将电弧加在药芯焊丝和焊接熔池之间的一种焊接工艺：该工艺在焊接时可以通过管状焊丝里面的焊剂得到保护(自保护)。也可以由外部提供的气体受到保护(气体保护)。     

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.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

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.