材料期刊网

SIMULATON ON WELDING PROCESS OF T - JOINTS

H. Y. Zhao , A. L. Lu , Q. Y. Shi and F. Yan (Welding Division , Department of Mechanical Engineering , Tsinghua University , Beijing 100084 , China)

金属学报(英文版)

T-joints are widely used in ship manufacturing and other welding structures.The welding residual stress and deformation hare significant influence on failure and service life in welding structures.By us- ing of 3D thermal elasto - plastic FEM, the temperature fields,stress fields and deformation of weld- ing processes on T - joints are analyzed in this paper.The moving heat source is considered in the com- putation. Moreover, weld metal filling and multiple - pass welding are simulated using activate/deac- tivate ability.For avoiding "locking" in full integration elements of welding computation,the re- duced intergration elements are used in weld area.The nonlinear FEM analysis program MARC is used to complete the computations, as well as its user subroutines that are programmed to develop the special techniques needed in the simulation of welding process.Some different welding procedures are com- pared, and the welding residual stress and deformation are discussed in details.

关键词: welding , null , null , null , null

冷轧Q195F钢种退火工艺制度的优化

崔勇 , 李驭 , 佟强

物理测试 doi:10.3969/j.issn.1001-0777.2000.06.007

介绍了从德国引进的全氢罩式退火炉的特点，结合本钢冷轧厂的生产实际情况，分析了影响Q195F钢种退火工艺的多种因素，对主要产品Q195F钢种的退火工艺制度进行了优化。

关键词: 罩式炉 , 退火 , 工艺优化

Experimental Investigation on the Performance of Armour Grade Q&T Steel Joints Fabricated by Flux Cored Arc Welding with Low Hydrogen Ferritic Consumables

G. Magudeeswaran

材料科学技术（英文）

Quenched and Tempered (Q&T) steels are widely used in the construction of military vehicles due to its high strength to weight ratio and high hardness. These steels are prone to hydrogen induced cracking (HIC) and softening in the heat affected zone (HAZ) after welding. The use of austenitic stainless steel (ASS) consumables to weld the above steel was the only available remedy to avoid HIC because of higher solubility for hydrogen in austenitic phase. Recent studies revealed that low hydrogen ferritic (LHF) steel consumables can also be used to weld Q&T steels, which can give very low hydrogen levels in the weld deposits and required resistance against cold cracking. Hence, in this investigation an attempt has been made to study the performance of armour grade Q&T steel joints fabricated by flux cored arc welding with LHF steel consumables. Two different consumables namely (i) austenitic stainless steel and (ii) low hydrogen ferritic steel have been used to fabricate the joints by flux cored arc welding (FCAW) process. The joints fabricated by LHF consumable exhibited superior transverse tensile properties due to the presence of ferrite microstructure in weld metal. The joints fabricated by ASS consumable showed higher impact toughness due to the presence of austenitic phase in weld metal microstructure. The HAZ softening in coarse grain heat affected zone (CGHAZ) is less in the joints fabricated using LHF consumable due to the lower heat input involved during fabrication compared to
the joints fabricated using ASS consumables.

关键词: Quenched and tempered steel , null , null , null

Improving glass-forming ability of Mg-Cu-Y via substitutional alloying: Effects of Ag versus Ni

Journal of Materials Research

Based on the best bulk metallic glass (BMG) forming alloy in the Mg-Cu-Y ternary system, we introduced Ag (or Ni) to partially substitute for Cu to improve the glass-forming ability (GFA). The objective of this paper is twofold. First, we illustrate in detail a recently developed search strategy, which was proposed but only briefly outlined in our previous publication [H. Ma, L.L. Shi, J. Xu, Y. Li, and E. Ma: Discovering inch-diameter metallic glasses in three-dimensional composition space. Appl. Phys. Lett. 87, 181915 (2005)]. The protocol to navigate in three-dimensional composition space to land large BMGs is spelled out step-by-step using the pseudo-ternary Mg-(Cu,Ag)-Y as the model system. Second, our ability to locate the best BMG former in the composition tetrahedron allows us to systematically examine, and conclude on, the effects of a given alloying element. The large improvement in glass-forming ability in the Mg-(Cu,Ag)-Y system relative to the based ternary will be contrasted with the reduced glass-forming ability in the Mg-(Cu,Ni)-Y pseudo ternary system. It is demonstrated that the improvement of glass-forming ability requires judicious choice of substitutional alloying elements and concentrations, rather than simple additions of multiple elements assuming the "confusion principle."

关键词: bulk metallic-glass;shaped copper mold;amorphous-alloys;thermal-stability;ternary-system;casting method;p system;diameter;zr;mm

马普协会煤化所和F. Schüth教授的研究活动

陆安慧

新型炭材料 doi:10.3969/j.issn.1007-8827.2003.04.014

关键词:

RbLn2F7的水热合成及RbLn2F7:Eu3+(Ln=Gd,Y)的VUV光谱

由芳田 , 黄世华 , 王大伟 , 黄艳 , 徐建华

中国稀土学报

利用水热方法合成出RbLn2F7(Ln=Gd,Y,Er,Yb和Lu),均为六方RbEr2F7型结构.掺杂Eu3+离子样品的光谱表明水热产物中氧杂质含量极低.在RbGd2F7:Eu3+(0.5mol%)的激发光谱中只观测到Gd3+离子f-f跃迁,Eu3+离子的激发跃迁很弱.激发Gd3+离子到6IJ能级后,观测到Eu3+离子的特征发射,Gd3+离子与Eu3+离子之间存在能量传递过程.Eu3+离子的5D0→7F1和5D0→7F2跃迁发射较强,表明稀土离子在六方RbLn2F7中处于非中心对称的格位.

关键词: RbLn2F7 , 水热合成 , 真空紫外(VUV) , 氟化物 , 能量传递 , 稀土

Y0.78Yb0.2Er0.02F3多孔纳米粒子的合成与上转换发光

杨梅 , 刘其鹏 , 李东风 , 尤洪鹏 , 洪广言

中国稀土学报

以Y2O3,Yb2O3,Er2O3,NH4F等试剂为原料,采用水热法在180 ℃下保温10 h获得了NH4Y1.56Yb0.4Er0.04F7球形纳米粒子. 所获得的纳米粒子在氮气保护下400 ℃灼烧2 h,制备出Y0.78Yb0.2Er0.02F3纳米粒子. 利用Scherrer公式计算出NH4Y2F7:Yb3+,Er3+和YF3:Yb3+,Er3+的粒径分别为65.8和68.3 nm. TEM照片展示粒子近球形,其大小与Scherrer公式计算结果一致. TEM还揭示每个粒子上面应带有许多小孔. 氮气吸附脱附实验进一步证实了粒子上存在小孔. 在980 nm的红外激光激发下,NH4Y1.56Yb0.4Er0.04F7不发光,而Y0.78Yb0.2Er0.02F3发出明亮的绿光,表明所获得的Y0.78Yb0.2Er0.02F3具有强的上转换发光.

关键词: NH4Y1.56Yb0.4Er0.04F7 , Y0.78Yb0.2Er0.02F3 , 纳米粒子 , 水热法 , 上转换发光 , 稀土

TANDEM and GMAW Twin Wire Welding ofQ690 Steel Used in Hydraulic Support

FANG Chen-fu , MENG Xiao-hui , HU Qing-xian , WANG Feng-jiang , REN He , WANG Hai-song , GUO Yu , MAO Ming

钢铁研究学报(英文版)

Compared with using semi-automatic gas shielded arc welding, using automatic TANDEM twin wire welding and twin wire gas metal arc welding (GMAW) to weld Q690 steel, a low-alloy high-strength structural steel used in the hydraulic support in the fully-mechanized mining face, the welding speed, deposition rate, production environment and welding quality can be obviously improved. Compared with GMAW twin wire welding, a refined microstructure in the weld and heat-affected zone (HAZ), narrow HAZ and improved joint strength were achieved with TANDEM on Q690. Also, due to the push-pull pulsed way in TANDEM welding, the droplet transfer, distribution on heat flow and interaction between two arcs were completely different from those in GMAW twin wire system. The heat input of TANDEM is only about 766% of GMAW, and correspondingly, the welding speed and welding seam can be obviously improved. The complete oscillation caused by TANDEM pulsed current occurred in the welding pool, which refined the grains in the microstructure. The results show that TANDEM twin wire welding is very suitable in the welding of Q690 used in the hydraulic support.

关键词: Q690 steel , TANDEM twin wire welding , GMAW twin wire welding , performance analysis , hydraulic support

Na(Y1.5Na0.5)F6∶Eu3+的热稳定橙色发光及荧光增强

庞涛 , 周元

功能材料 doi:10.3969/j.issn.1001-9731.2017.04.023

采用简单的水热工艺制备了六方相Na(Y1.5 Na0.5)F6∶Eu3+荧光粉.300 K温度下利用394 nm光波长激发,观察到Eu3+的5Dn(n=0,1,2)→7 FJ(J=1,2,3,4)跃迁,对应主波长590 nm,色彩饱和度约为0.97.当温度升高到420 K时,仅观察到微小的色漂移.进一步拟合Ln(I0/I-1)和10 000/T的关系曲线,确定发光的热猝灭激活能约为0.324 eV.良好的热稳定性,表明Na(Y15Na0.5)F6∶Eu3+适合于功率器件的封装.在Na(Y1.5 Na0.5)F6∶Eu3+表面包覆二氧化硅后,可观察到Eu3+增强的发光,但这种荧光增强依赖于二氧化硅壳层的厚度.利用荧光增强与荧光猝灭的竞争模型解释了上述现象.

关键词: Na(Y1.5 Na0.5)F6∶Eu3+ , 热稳定性 , SiO2包膜 , 荧光增强

Revision of a CCT Diagram of the Simulated ADI Weld Metal and Its Application in Actual Welding

Deyuan LI , Zhenfeng ZHOU and Daqian SUN (Jilin University of Technology , Changchun 130025 , China)Chengji SHAO(Shenyang Polytechnical University , Shenyang 110023 , China)

材料科学技术（英文）

A continuous cooling transformation (CCT) diagram of the simulated ADI weld metal has been developed by means of the Formastor-F diagram measurement apparatus, and revised by comparing with the actual welding. Finally the revised diagram was used to determine the welding technology

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