管桩水泥性能优化与控制方法

预应力高强管桩是采用高标号品种水泥等原料作为原材料,经离心工艺成型后,再通过蒸汽或蒸压养护而成的一种空心圆筒体的等截面混凝土构件,具有脱模快、强度高、施工方便、适用范围广、生产成本低等优点,广泛应用于建筑、港口、码头、铁路、桥梁等基础设施建设工程中[1]。管桩制品厂家一般对水泥强度要求高,尤其是早期强度[2],另外因操作时间不长和对产品外观质量要求较高,相比普通的混凝土,对流动性要求更高。中国葛洲坝水泥有限公司长期向荆州、荆门等地的管桩生产企业供应管桩专用水泥,为更好地满足客户需求,提升公司管桩水泥产品的强度与工作流动性能,开展相关试验研究。     

Development of ultra-narrow gap welding with constrained arc by flux band

0 IntroductionThe merits of narrow gap welding (NGW) such ashigh productivity and quantity, minimal distortion, highcost-effectiveness, and all position capability are wellknown. The narrower the gap, the more significant the a-bove merits. Moreover, while an ultra-narrowgap welding(UNGW) process with less than 5 mm gap width is used,its some advantages are very useful for preventing thestress corrosion crack in austenitic steel piping, and forwelding some update steels. For example, in aus…     

工艺因素对82B钢280 mm x325 mm铸坯凝固过程的影响

为模拟不同工艺条件下的连铸坯的凝固过程,采用有限元法模拟了82B钢连铸的凝固过程,获得280 mm×325 mm连铸坯的温度场。结果表明,随拉速从0.60 m/min增加到0.76 m/min,凝固时f_s=1处与f_s=0处皆后移,但中心凝固时间反而增加了9.8%。随过热度由15℃增加到50℃时,凝固末端f_s=1处同样后移,约后移1.1 m。根据模拟结果改进连铸工艺,当拉速从0.60 m/min增加到0.76m/min,增加轻压下工艺可改善低倍质量。     

轴对称与非轴对称截面冷拔棒材表面残余应力的比较

用物理测定法测定了矩形截面冷技型钢表面的残余应力，并与圆形截面冷拔型钢表面残余应力进行比较。提出用高温近火方法来改善矩形截面冷拔型钢表面残余应力的工艺探索。     

Research and Applications of Semi-solid Processing

Since it was pioneered by Flemings and otherresearchers [11, the semi-solid metal processingtechnique has been widely stUdied in the world.Especially in the past decade, SSM as a newproduct forming technique has been rapidly developed and put into commercial applications[2, 31. In recent years, with the development ofthe ado-industry of China, a lot of researchwork on SSM has been done, including the preparation of slumes, reheating and thixoforming[Al6]; moreover, great achievements have …     

Zr替代Ti对Ti19．5V40Mn16．2Cr9．8Ni14．5合金的影响Ⅱ：电化学性能

在对合金微观结构和储氢性能研究的基础上，详细考察了少量Zr取代Ti对Ti19．5V40Mn16．2Cr9．8Ni14．5合金电化学性能的影响。通过观察电极的充放电行为，并结合EIS及多种极化曲线的分析结果，发现少量Zr对Ti的取代能够显著提高合金电极的实际电化学容量和循环稳定性，而且还能在一定程度上改善合金的电极动力学性能。对于这些性能的改善，从合金微观结构方面进行了解释。     

Multidisciplinary optimization of gas-quenching process

Distortion as a result of the quenching process is predominantly due to the thermal gradient and phase transformations within the component. Compared with traditional liquid quenching, the thermal boundary conditions during gas quenching are relatively simple to control. By adjusting the gas-quenching furnace pressure, the flow speed, or the spray nozzle configuration, the heat-transfer coefficients can be designed in terms of both the component geometry and the quenching time. The purpose of this research is to apply the optimization methodology to design the gas-quenching process. The design objective is to minimize the distortion caused by quenching. Constraints on the average surface hardness, and its distribution and residual stress are imposed. The heat-transfer coefficients are used as design variables. DEFORM-HT is used to predict material response during quenching. The response surface method is used to obtain the analytical models of the objective function and constraints in terms of the design variables. Once the response surfaces of the objective and constraints are obtained, they are used to search for the optimum heat-transfer coefficients. This process is then used instead of the finite-element analysis. A one-gear blank case study is used to demonstrate the optimization scheme.     

贵金属的化学发光分析

介绍化学发光分析的基本原理和测试技术,及其应用于测定贵金属的几种化学发光反应,并展望其前景。     

渗碳工艺CAD软件的研究开发

研究开发的渗碳工艺CAD软件,采用模块结构,菜单式操作,可对不同钢种进行不同渗碳工艺的工艺参数设计和渗碳过程模拟。