各种钢铁的焊接

20095199 高强合金钢中厚板双丝焊接接头组织性能／冯日海…／／焊接学报．-2009,30（6）：51-54 针对轻型车辆中厚板高强合金钢高效化焊接特点,基于高效双丝熔化极气体保护焊系统,应用双电弧共熔池熔化极气体保护焊方法,采用奥氏体不锈钢焊丝进行高强合金钢的焊接工艺试验。确定了合适的焊接工艺参数。并对获得的对接接头的显微组织、成分及力学性能进行了分析。     

各种钢铁的焊接

20095199 高强合金钢中厚板双丝焊接接头组织性能／冯日海…／／焊接学报．-2009,30（6）：51-54 针对轻型车辆中厚板高强合金钢高效化焊接特点,基于高效双丝熔化极气体保护焊系统,应用双电弧共熔池熔化极气体保护焊方法,采用奥氏体不锈钢焊丝进行高强合金钢的焊接工艺试验。确定了合适的焊接工艺参数。并对获得的对接接头的显微组织、成分及力学性能进行了分析。     

高强合金钢中厚板双丝焊接接头组织性能

针对轻型车辆中厚板高强合金钢高效化焊接特点,基于高效双丝熔化极气体保护焊系统,应用双电弧共熔池熔化极气体保护焊方法,采用奥氏体不锈钢焊丝进行高强合金钢的焊接工艺试验.确定了合适的焊接工艺参数,并对获得的对接接头的显微组织、成分及力学性能进行了分析.结果表明,采用双电弧共熔池熔化极气体保护焊工艺,能够获得良好的中厚板高合金钢焊接接头,力学性能满足使用要求.与焊条电弧焊和单丝电弧焊相比,焊接效率得到较大提高.     

焊接工艺过程对中厚板埋弧焊应力场影响的数值模拟

通过ANSYS有限元分析软件,采用热-应力直接耦合分析法对低碳钢中厚板埋弧焊焊接温度场与应力场进行了模拟分析,并比较了单面双层焊、正反双面依次焊和正反双面同时焊三种焊接工艺过程对接头焊接残余应力的影响。     

焊接工艺过程对中厚板埋弧焊应力场影响的数值模拟

通过ANSYS有限元分析软件，采用热-应力直接耦合分析法对低碳钢中厚板埋弧焊焊接温度场与应力场进行了模拟分析，并比较了单面双层焊、正反双面依次焊和正反双面同时焊三种焊接工艺过程对接头焊接残余应力的影响。     

双丝焊接工艺参数对中厚板打底焊缝形貌的影响

针对中厚板双丝打底焊件侧弯性能测试后发现的侧壁熔合深度较小的焊件从熔合线处开裂的问题,研究了双丝打底焊工艺参数(对接间隙、焊接速度、前丝电流、后丝电流)对焊缝形貌和侧壁熔合深度的影响规律和影响大小,结果表明,各工艺参数对侧壁熔合深度的影响由大到小为:对接间隙、后丝电流、焊接速度、前丝电流。探索出侧壁熔合深度良好的工艺参数区间,通过二次回归方程建立了打底焊缝成形良好范围内的工艺参数对侧壁熔合深度的预测模型。     

关于钨极氩弧焊热源模型适用性的探讨

采用Ansys有限元计算软件，模拟平板对接钨极氩弧焊时的三维动态温度分布。分别采用高斯分布函数、双椭球分布函数两种不同的热源分布模型进行加载，比较两种热源模型下计算出的温度分布情况差异。采用模拟时的焊接工艺参数进行钨极氩弧焊平板对接焊，测定焊接热循环曲线和焊缝截面尺寸，对模拟结果加以验证。结果表明，采用双椭球热源模型时的计算结果与实测结果吻合较好。     

中等厚度板埋弧焊焊缝研究

采用不同碳当量的焊丝WGX1和WGX2等对多种中厚板进行了埋弧焊试验及焊缝拉伸试验,对接焊缝强度与焊丝熔敷金属强度相比有明显的变化,建立了强度的变化量与焊丝及母材的碳当量差值的关联性,为控制中厚板埋弧焊缝强度奠定了基础。     

超低碳奥氏体不锈钢陶瓷衬垫单面焊双面成型焊接工艺试验

超低碳奥氏体不锈钢中厚板的全位置对接焊在工业上被广泛使用,采用适合平直与曲面焊缝的陶瓷衬垫,进行全位置单面焊双面成型半自动焊接,可大幅度提高不锈钢的焊接工效和质量。研究表明,采用该工艺后不锈钢焊接接头的各项力学性能、抗晶间腐蚀性能、宏观金相结果均符合CCS船级社规范检验要求。     

大型双丝PMIG焊机器人焊接装备开发及工程化应用的研究

重点阐述大型高效双丝PMIG焊机器人焊接装备技术的研发过程,包括数字化双丝PMIG焊系统、高速焊激光跟踪装置、弧焊机器人+龙门架+变位机的11轴焊接装备的构成及设计技术;介绍了装备在风塔机架大型中厚板构件焊接中的工程化应用案例。     

焊接温度场和应力场的热弹塑性有限元分析

针对低碳钢薄板件TIG对接焊工艺 ,应用双椭圆分布热源模型 ,建立了TIG对接焊三维温度场有限元数值分析模型 ,将温度场有限元解同实验结果进行了比较 ,两者吻合较好。在此基础上 ,考虑材料非线性并采用热弹塑性有限元方法 ,得到了不同时刻热应力场的演化过程 ,为焊接残余应力和变形的研究打下了基础。     

双锥形件同时旋压成形的应力应变场有限元分析

提出了双锥形件旋压加工的一种新方法.基于ABAQUS/Explicit平台建立了双锥形件同时旋压成形三维有限元模型,结合金属塑性变形原理和旋压工艺的特点,确定了旋轮成形面角度、旋轮径向进给速度、主轴转速、摩擦系数等工艺参数的取值范围;进而获得了双锥形件同时旋压成形过程中应力场、应变场的分布特点,为双锥形件同时旋压成形后...     

电弧气刨对板材初始应力场的影响

根据电弧气刨的特点,用有限元的方法分析了电弧气刨对10Ni5CrMoV钢板材应力场的影响规律,并进行了试验验证,模拟结果和试验结果吻合良好.在此基础之上,进一步分析了电弧气刨应力场规律及其对初始应力场的影响机理.结果表明,电弧气刨稳态应力场和平板对接焊稳态应力场相似,在靠近坡口处为拉应力状态,在到达峰值后残余拉应力逐渐变小,并且纵向残余应力变为压应力,而横向残余应力趋近于0应力状态.电弧气刨对于板材应力场影响包含两个方面:(1)材料的去除释放板材坡口处的初始应力;(2)电弧的热作用导致坡口处产生较大的残余拉应力,电弧的热作用对应力场的影响更为强烈.     

Investigation of electrohydrodynamic flows in superstrong electric fields

The results of the experimental investigation of EHD flows arising in a system with a highly nonuniform electric field are presented. A high degree of the nonuniformity distribution of the electric field is obtained due to using an active needle electrode with a 3 μm curvature radius. The stationary and dynamic current-voltage characteristics and the dependence of the EHD flow velocity on the voltage are obtained. It is shown that, at a high rate of the voltage modulation, the dynamic current-voltage characteristics have a hysteresis. The investigation of the electron-acceptor admixture’s influence on the form of the current-voltage characteristics and the intensity of the EHD flows is conducted. A return EHD flow arising after the voltage’s turning off is recorded. The obtained results are compared with similar data in the literature for the case of less nonuniform electric fields.     

焊接工艺参数对温度场的影响研究

着重针对焊接电流、焊接速度、焊缝间隙以及焊枪偏离焊缝中心的偏心值4个焊接工艺参数进行了TIG焊接试验研究。采用正交设计方案并利用红外测温仪测量和记录焊件正面上设定点的热循环曲线，将之与三雏焊接温度场的有限元数值解进行比较，两者基本吻合，表明了数值计算模型的有效性。以某点热循环中的峰值温度作为温度场代表，结合正交试验理论，分析上述4个工艺参数对于温度场的影响次序，表明偏心值对焊接温度场的影响最大。     

Effect of high magnetic fields on the solidification microstructure of an AI-Mn alloy

The effect of high magnetic fields on the morphology of Al-Mn phases was investigated. It is found that the tropism and the alignment of Al6Mn precipitated phases become regular under high magnetic fields. The stronger the high magnetic fields, the more regular the alignment of AI6Mn precipitated phases. Al6Mn precipitated phases can generate oriented alignment and aggregation under high magnetic fields through the observation of the quenched microstructure of the Al-Mn alloy at different temperatures. Meanwhile, the number of Al6Mn phases increases continuously along with the increasing function time of high magnetic fields. X-ray diffraction also indicates that Al6Mnphases generate obvious tropism under high magnetic fields. The process of aggregation and growth of Al6Mn precipitated phases under the function of high magnetic fields after orientation were analyzed and discussed.     

Homology metrics for microstructure response fields in polycrystals

Quantitative homology metrics are proposed for characterizing the thermal–elastic response of polycrystalline materials. Simulations for a calcite-based polycrystal, marble, are used as an illustrative example. The homology metrics are based on topological measurements, such as the number of components and the number of handles of the thermal–elastic response fields for a complex microstructure. These homology metrics are applied to characterize not only the elastic energy density and maximum principal stress response fields in a polycrystal but also the correlated grain-boundary misorientation distributions that influenced the formation of these response fields. It is demonstrated that the topological analysis can quantitatively distinguish between different types of grain-boundary misorientations, as well as between differences in the resulting response fields.     

Strong stray fields in magnets with a nonuniform distribution of the magnetization

Stray fields produced by magnets in the form of a cylinder in which the vector of magnetization at each point is directed along the cylinder radius have been calculated. It was assumed that this distribution of magnetization was achieved due to the presence of a radial crystalline texture and the related magnetic anisotropy with a large field of the uniaxial anisotropy H _K . It has been shown that the greatest stray fields are reached on the surface of the magnet at points that are located near its axis, and the limiting value of the point field is equal to 4πM _S ln(a/r). It has been established that in magnets with a radial magnetization the region of localization of strong fields H > 4πM _S substantially exceeds that characteristic of the systems of magnets with a uniform magnetization.     

小截面薄壁方管并行焊接温度场及变形的数值模拟

小截面薄壁方管在焊接过程中变形严重,且与胎具之间的传热情况复杂,所以采用传统的单向顺序耦合方法计算的温度场误差较大.对此,文中建立了考虑接触热传导的小截面薄壁方管并行焊接的直接耦合分析模型.通过与实测结果比较,模拟得到的温度场与实测结果有较好的吻合,表明该模型能准确的反映方管与胎具间的传热过程,证明了模型的可靠性和正确性,为自动化焊接各项参数的合理选择和优化提供了有效的参考依据.     

On the determination of residual stress and strain fields by sharp indentation testing.: Part I: theoretical and numerical analysis

Sharp indentation tests, presently represented by cone and Vickers indenters, are analysed theoretically and numerically in order to explore how equi-biaxial residual stress and strain fields can be determined from the global properties, i.e. the size of the contact area between indenter and material and the hardness, given by such tests. It is shown that the residual strain fields can be accurately correlated with the hardness value while residual stresses are related to the size of the contact area. The latter feature is explained by the fact that the size of the contact area is sensitive to elastic effects. The results are summarized in simple closed form relations, well-suited to be used in an experimental situation, and the range of validity for the resulting formulae is discussed. The predictions are compared with corresponding results taken from the literature and good agreement is found. An experimental scheme for determination of residual fields by indentation is also suggested.