Q345R与NS3306/NS1402异种钢的焊接

根据Q345R与NS3306/NS1402异种钢材料及其焊接特性,选择ENiCrMo-3型焊条作为异种钢对接焊的焊接材料,分别进行了Q345R+NS3306、Q345R+NS1402的焊接工艺评定试验,能够保证焊接接头的力学性能,并在产品的实际焊接过程中,结合镍基材料的焊接特点提出焊接操作要点,确保产品焊接质量。     

压力容器不锈钢复合板焊接工艺开发

S31603/Q345R不锈钢复合板由于其材料和结构的特殊性，兼具了不锈钢的耐腐蚀性和低合金钢的强度等优点，在海洋钢结构压力容器生产中的应用越来越广泛。本试验中采用埋弧焊+氩弧焊、埋弧焊+焊条电弧焊和焊条电弧焊3种焊接工艺，选择适当的焊接材料、坡口形式和焊接工艺参数对厚度(3+18) mm的经爆炸焊复合形成的S31603/Q345R不锈钢复合板分别进行对接焊试验，分析其焊接接头的力学性能及腐蚀性能，其结果均满足要求。     

06Cr19Ni10与Q345R焊条电弧焊焊接工艺

06Cr19Ni10钢与Q345R钢焊接的主要问题是,多层多道焊时,靠Q345R钢的一侧(焊缝根部的焊趾线上)易产生未熔合与夹渣.作者通过参与一台余热锅炉锅筒的焊接试验、焊接工艺编制与锅筒制造,研究06Cr19Ni10与Q345R钢的焊接及焊接缺陷产生的原因、避免缺陷产生的工艺措施以及产生缺陷后如何进行返修等几个方面.同时阐述了06Cr19Ni10与Q345R异种钢的焊接工艺和方法.     

Q345R和S30408异种钢焊接接头组织与性能分析

异种钢焊接在各工程领域中应用广泛,但由于异种钢在冶金相容性、物理和化学性能方面差异较大,接头组织不均匀,力学性能较差,因此有必要研究其组织及性能。选用A302焊条,采用焊条电弧焊(SMAW)对Q345R和S30408异种钢进行焊接,并进行焊后热处理,利用微观金相组织观察,冲击、弯曲及拉伸等力学测试分析焊接接头的组织和力学性能。实验结果表明:Q345R和S30408异种钢焊接接头具有优良的力学性能,抗拉强度达到569 MPa以上,-20℃低温平均冲击功达到48 J以上,材料最佳热处理温度为550℃。     

隧道掘进机中40CrNiMoA与Q345C异种钢的焊接工艺

针对隧道掘进机主梁支撑推进系统中材质为40Cr Ni Mo A的撑靴体球头和材质为Q345C撑靴体底板的异种钢材焊接工艺特点和实际生产的需求,分析了这2种材料的焊接性;通过选择合适的焊接材料、焊接工艺措施,采用熔化极富氩气体保护焊方法对40Cr Ni Mo A与Q345C异种钢进行焊接,并对焊接接头进行无损检测、金相组织观察和力学性能试验。试验结果表明,所制定的焊接工艺能够获得满意的焊接接头质量。     

一种有效提高不锈钢复合板焊接质量的措施

不锈钢复合钢板的基层与复层交界处的焊接属异种钢焊接,其焊接性受复层和基层的物理性能、化学性能、接头形式及填充金属等多种因素的影响,常产生焊接裂缝等问题。通过分析压力容器中筒体纵缝、筒节间和筒节与封头间的环缝焊接质量,探索在具体项目中,不锈钢复合板焊接合格率低的成因,提出了采用组合坡口设计和改变焊接顺序的具体改进措施。通过实施改进措施,将压力容器Q345R/S31603不锈钢复合板的焊接合格率从78%提升到了100%。     

S355J2G3与Q345R低合金钢焊接接头耐腐蚀性能对比研究

通过周期浸润腐蚀试验,对比研究了S355J2G3和Q345R低合金钢焊接接头的耐腐蚀性能,并用扫描电镜对腐蚀产物进行了观察和分析.结果表明:在相同试验条件下,S355J2G3钢焊接接头的失重率低于Q345R的;Q345R钢焊接接头表面附着橘红色的疏松麻点状锈层,S355J2G3钢焊接接头表面初期也出现了橘红色的锈层,随着试验的进行,锈层颜色逐渐加深,变为黑褐色,组织较致密;Q345R钢焊接接头的腐蚀产物结构主要为块状和粉末状,形状无规则,同时锈层中存在裂纹和缝隙;S355J2G3钢焊接接头的腐蚀产物为块状和针状.     

Q345qD与Q390GJC异种材质焊接性能研究

以Q345qD钢与Q390GJC钢的焊接为例,详细介绍了异种材质焊接的工艺过程,并分析了焊接接头金相组织、力学性能以及显微硬度。结果表明,Q345qD钢与Q390GJC钢具有良好的焊接性,在采用合理的焊接工艺参数后,接头力学性能及微观金相均能满足规范要求。     

0Cr13Ni5Mo+Q345异种钢焊接工艺

介绍了一种新型焊接材料SW—309L超低碳不锈钢药芯焊丝用于0Crl3Ni5Mo Q345异种钢焊接。从母材性能、焊接材料的选择、焊接工艺评定等方面予以详细地分析和验证。     

特厚板GMAW和SAW的焊接热影响区宽度

采用宏观金相试验和显微硬度测试的方法,测量了ZG300-500H/Q345R异种钢二氧化碳气体保护焊(GMAW)和Q345R钢埋弧焊(SAW)的热影响区宽度。宏观金相观察结果表明：GMAW焊接接头的ZG300-500H和Q345R两侧热影响区平均宽度分别为2.01 mm、1.71 mm; SAW焊接接头的热影响区平均宽度为4.63 mm。硬度试验结果表明：GMAW焊接接头的ZG300-500H和Q345R两侧热影响区平均宽度分别为2.33 mm、2.17 mm; SAW焊接接头热影响区宽度为4.71 mm。     

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).     

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.     

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.     

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。