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1.
殷浩澍 《电焊机》2005,35(7):1-5,64
为了在竞争中获胜,欧洲造船业必须提高生产速度和效率,同时降低成本。因此,他们投入了巨大的人力和财力来研发激光焊接并将其应用到造船生产实践中,以达到维持和重建欧洲船厂在全球高附加值船舶市场的优势地位。  相似文献   

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李廷梁 《贵金属》2000,21(2):63-66
概括介绍俄罗斯金冶金技术发展状况,以飨读者。  相似文献   

4.
介绍的数值鼠标技术对提高视觉对色彩的分辨精度提供了一个非常好的解决方案。通常用于模拟凝固过程的动画AVI,类似于电影电视,缺乏互动能力,只能在固定的视场、视角下观看固定的序列画面。介绍的实时动画与实时拖动技术使用户在观察模拟结果时,在动画行进的同时,可以随意旋转、缩放、进格、退格等。  相似文献   

5.
挤压铸造合金材料的研究进展   总被引:7,自引:9,他引:7  
简述了合金材料压力下结晶的强化机理研究状况;讨论了挤压铸造铝合金、锌合金、镁合金及其复合材料的研究进展;指出合理的挤压铸造工艺可细化合金显微组织,提高铸件致密性,改善合金力学性能.  相似文献   

6.
This article presents a paradigm for the mechanical properties of a metal that result from the plastic deformation that occurs in forming processes, including multiple-step or cyclic processes. Some of the new concepts included are a new strength designation that includes the sense (tensile or compressive), the direction (longitudinal, transverse, etc.), the specific type of deformation (tensile, compressive, etc.); a concept of an equivalent strain; and the apparent rules of strain strengthening. Examples of strength  相似文献   

7.
The design of ultrasonic butt welded joints in rigid plastics with additional compressive force is investigated. Two methods of introducing the energy of ultrasonic oscillations in the immediate vicinity of the welding zone with the tangential introduction of the oscillations and the relative displacement of the welded elements in the joint plane and welding with two-sided tangential introduction of the oscillations are discussed.  相似文献   

8.
用EPS做模型,干砂造型在负压的状态下浇注碳钢,系统研究影响各种工艺条件下EPC法生产碳钢件内部增碳的因素。发现模型分别用石英粉、刚玉粉、锆英粉3种涂料涂覆,浇注碳钢件均有内部增碳现象发生,其中使用石英粉涂料的铸件内部增碳较小,采用底注式浇注,同一铸件随着铸件高度的增加,内部增碳增加。另外,随真空度的增加内部增碳减小。  相似文献   

9.
Progress in application of rare metals in superalloys   总被引:1,自引:0,他引:1  
Rare metals play an important role in development of superalloys. Over the last two decades, the application of the rare metals in superalloys has achieved progress significantly. They present multi-beneficial effects for strengthening the matrix and the c0phase, increasing the lattice misfit, cleaning the grain boundary, improving the carbides and eutectics, refining the grain, stabilizing the oxidation film, etc., so that the elevated temperature rupture life and elevated temperature oxidation resistance are improved significantly, leading to a broad application in the superalloys. In order to meet the higher demand for better superalloys in the future, more intensive research is necessary on the effects of the rare metals on the superalloy, and especially on the combination effect of various rare metals and mutual influence among them. Utilization of the computational materials science and combinatorial high throughput experiment will be of importance in application of rare metals in superalloys.  相似文献   

10.
半固态合金流变铸造的研究进展   总被引:15,自引:22,他引:15  
总结了30余年来半固态合金流变铸造的研究和应用现状。介绍了传统机械搅拌式流变铸造工艺,由于其所制备的半固态合金浆料保存、输送麻烦,至今没有进入实际应用;评述了射室制备浆料式流变铸造工艺技术,其生产的压铸件经T6处理,力学性能与挤压铸件相当,但伸长率提高很多;介绍单、双螺旋流变射铸工艺,其特点是利用液态合金原料生产成本低,铸件气孔率低,但其所需设备和生产工艺还处在优化阶段;重点介绍了低过热度倾斜板浇注式流变铸造、低过热度浇注和弱机械搅拌式流变铸造的工艺特点和核心思想;分析了半固态合金流变铸造的发展前景。  相似文献   

11.
我国熔模铸造的可持续发展   总被引:2,自引:2,他引:2  
介绍了我国环保方面的法律、法规和标准,并结合熔模铸造工艺的实际情况,剖析了从制模、制壳、熔炼、浇注、以及清理、切割等熔模铸造生产过程中,经常可能出现的污染源.在此基础上对我国熔模铸造的可持续发展,提出了一些意见和建议。  相似文献   

12.
铝土矿酸介质中铁的行为   总被引:4,自引:1,他引:4  
研究了高温高压条件下铝土矿中铁在硫酸介质中的溶解行为,结果表明:在一定的温度条件下,铝土矿的赤褐铁矿能较好地溶于硫酸溶液中,而铝土矿中含铝矿物的性质不发生变化,从而为铝土矿的进一步加工利用提供了条件。详细讨论了反应温度、反应时间、硫酸浓度、液固比等因素对铁的溶解行为的影响,得出了在最佳工艺条件,即在反应温度160℃、反应时间3h、硫酸浓度0.7mo1/L和液固比6:1时除铁效率最高。  相似文献   

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14.
本文详细分析了低温环境下电厂钢结构焊接和管道焊接产生冷裂纹及延迟裂纹的各种因素,并从焊接方法的选择、焊前预热、层间温度的控制、焊接热输入量、焊后保温等方面采取了质量控制措施,从而防止了焊接冷裂纹和延迟裂纹的产生,保证了低温环境下的焊接质量。  相似文献   

15.
Diffusion coefficients and mobilities were determined as functions of concentration in the a phase of the Cu-Zn system. Use was made of incremental diffusion couples to determine the Kirkendall effect at various concentrations. Darken’s analysis was used to calculate the individual diffusion coefficients and mobilities from these data. The general diffusion coefficient is a single-valued function of the concentration in this system to within the limits of accuracy of the experimental methods used. The form of the various functions (diffusion coefficients and mobilities) of concentration is the same in every case: it is essentially the same as the usual D vs c curve.  相似文献   

16.
陈春怀 《热处理》2013,(6):74-77
聚合物淬火剂由于其显著的优点应用日益广泛。但使用中往往会滋生细菌,不仅加速了聚合物淬火剂的老化,而且有加速工件生锈、影响环境卫生等弊病。聚合物淬火剂中细菌的滋生与所用聚合物和水的质量,淬火系统的循环状况,pH值,杂屑杂油以及空气中的细菌等因素有关。使用好富顿生物稳定的产品AquaQuench245是一个解决细菌滋生的最佳方案。  相似文献   

17.
日晷由锡青铜铸造,其铸造技术的关键是防止大平面的变形和保证良好的充型以获得完整、清晰的表面。采用在日晷大平面背面设置加强筋和倾斜浇注工艺,成功地铸造完成了日晷铸件。  相似文献   

18.
耐高温铝液腐蚀-磨损材料的研究进展   总被引:1,自引:0,他引:1  
综述了耐高温铝液腐蚀-磨损材料的发展现状,对目前国内外的耐高温铝液腐蚀-磨损材料的选用、抗铝合金熔液腐蚀以及摩擦磨损的研究新进展进行了评述。指出了高温合金、金属间化合物和陶瓷/金属复合材料是耐高温铝液腐蚀-磨损材料的重点研究方向。  相似文献   

19.
钢中珠光体相变机制的研究进展   总被引:7,自引:1,他引:7  
简要总结了钢中珠光体相变的机制,特别是珠光体形核的晶体学和长大的动力学。基于形核时的最小形核能和渗碳体与铁素体“合作”生长的要求,珠光体通常在奥氏体晶界形核并只向某一晶粒内生长,因而晶界珠光体与相邻晶粒存在特定取向关系而与生长进入的晶粒无特定取向关系。晶体学研究表明,珠光体形核的领先相与碳浓度及渗碳体与铁素体间的取向关系(分别为Pitsch-Petch、Bagaryatsky或lsaichev)无关。最近的研究发现,具Bl结构的非共格杂质粒子界面是过共析钢中晶内珠光体形核的有效位置,初步的结果表明,晶内珠光体形核的原因在于杂质粒子生长造成的局部区域碳贫化及低能的珠光体,杂质界面取代高能的奥氏体,杂质界面。特定过冷度下的层片间距与正向界面推移速率的关系是珠光体生长动力学的主要问题。基于珠光体与奥氏体间的无序界面假设和稳态扩散方程分别发展了以体扩散控制和以界面扩散控制为主的动力学理论。两种理论均与实验结果符合较好,但后者似更合理。最近的实验在珠光体中发现了生长台阶与结构台阶,表明生长动力学方程需要修正。  相似文献   

20.
Abstract

Developments in some difficult repair welding technologies in Japan during the past decade are reviewed. The topics covered include the repair welding of bridges in service, the temper bead method which makes it possible to omit post-weld heat treatment (PWHT) of repaired pressure vessels, the seal welding of a reactor vessel in which stress corrosion cracks were detected, low heat input repair welding of neutron irradiated stainless steel and nickel based alloys, the prevention of solidification cracking in repair welding of aged heat resistant cast steels, the development of welding materials for the mending of single crystal nickel based superalloy turbine blades, underwater repair welding of nuclear reactors, the reduction of residual stresses in repair welding, and an ultrasonic testing method for nickel based weld metals. The local PWHT of creep resistant ferritic steel tubes is also reviewed.  相似文献   

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