半固态铸造技术研究现状与展望

半固态铸造是一种新的材料成形技术，综述了半固态铸造合金的组织变化、坯料制备、充型过程数值模拟和应用等方面的研究成果，同时对我国发展半固态铸造技术提出了若干值得重视的问题。     

高速线材轧机锥套故障分析与改进

高速线材生产线精轧机、预精轧机使用的锥套，在材质、结构、处理工艺及生产操作上存在诸多不当之处，为此进行了多项改进，使锥套故障彻底排除，使用寿命达3～5月，而价格仅为进口件的1／3。     

Influences of melt treatment on grain sizes and morphologies of AZ91D alloy

Influences of the three melt treatment processes （namely, refinement with carbon inoculation, electromagnetic stirring and ＂refinement ＆ electromagnetic stirring＂ processing） on the microstructures of AZ91D alloy were explored experimentally. The results indicate that the micron carbon powders inoculation processing with 0.1% （mass fraction） addition level makes the grain size of the primary phase （a-Mg） decrease to approximate 40% that of the initial primary crystal, from about 530 μm to 200 μm around. The electromagnetic stirring processing not only decreases the grain sizes sharply, but also transfers the grain shape of a-Mg from coarse dendritic to nearly spheralitic with the shape factor from about 0.1 to approximate 0,8. And the ＂refinement ＆ electromagnetic stirring＂ processing improves grain shape of a-Mg further and refines grain size to about 72 μm, less than 15% that of the initial primary crystal.     

熔体处理及电磁搅拌对AZ91D合金组织的影响

利用金相显微分析等手段，研究了熔体处理及电磁搅拌对AZ91D合金组织的影响。结果表明，C粉对AZ91D合金晶粒具有明显的细化作用，优于C2Cl6和Al—10Sr间合金，无水FeCl3、Al-5Ti—B测效果甚微。熔体处理与电磁搅拌复合作用使AZ91D合金晶粒转化为均匀细小的类球状半固态组织，作用优于单纯的电磁搅拌。     

CO2焊短路过渡过程的高速摄影研究

介绍利用高速摄影技术研究CO2焊短路过渡过程，指出高速摄影应根据研究对象的具体特点和研究目标等因素选择最适合的拍摄方案。通过对普通短路过渡过程和波形控制短路过渡过程各有侧重点的高速摄影研究，分别观察了不同条件下短路过渡过程中熔滴和电弧的形态，表明适当选择拍摄方案有利于对CO2焊短路过渡过程多方面特征的研究。     

Leaded brass rods C 38500 for automatic machining operations: A technical report

C 38500 is a widely used copper alloy with a great variety of applications from decoration and architecture to mechanical/electrical engineering. The chemical composition of this alloy offers superior machinability and subsequently increased productivity in high-speed machining and manufacturing processes. In European countries, this alloy is used primarily as free cutting brass (CW 614N according to EN 12164: 1998), similar to C 36000 alloy, which is used also for thread rolling. The lower percentage of Cu compared to C 36000 (nominal 58% instead of 61%) decreases the cost of the raw materials. This paper reports the principal aspects of microstructure, mechanical properties, and machinability of this alloy in relation to the industrial manufacturing process used.     

CO2激光焊接不锈钢光致等离子体动态特性分析

光致等离子体是CO2激光焊接中一个重要的物理现象，它与焊接的稳定性、焊接质量及能量利用率等都有密切的关系。利用高速摄像及光信号监测两种手段对等离子体的动态变化过程及其对焊接稳定性的影响进行了深入的研究。提出了等离子体的变化每个周期内分为四个阶段，而影响焊接稳定性的根本原因是等离子体在穿透与未穿透之间的波动。     

高线粗中轧机"浮动"检测结构设计及故障排除

为克服轧制中因机架锁紧功能降低而产生的机架沿轨座轴向移动的"浮动"现象,对其产生原因进行了分析,并通过改进锁紧装置结构及相关部件,使"浮动"故障得到预防和有效控制并及时排除。     

Development of magnesium composite alloy by a new method combining B2O3 addition and melt stirring

For developing high performance magnesium alloys, a new method in combination of B2O3 addition and melt stirring was applied. When 0.3%, 6% and 12%（ mass fraction） B2O3 was added into pure Mg, many twins were produced in each alloy. The average grain size of Mg was about 200 μm. In Mg-6Al alloy, the grain size is decreased from 50 to 35 μm by B2O3 addition. In Mg-6RE （rare earth） alloys, the grain size is decreased from 35 to 15 μm. The grain size of Mg-9Al- 6Ti-3B2O3 alloy is about 5 μm. The hardness of pure Mg does not change by B2O3 addition. In Mg-6Al alloy, the hardness is increased by addition of 3% B2O3, however, the hardness of Mg-6RE alloy is decreased by B2O3 addition. Addition of B2O3 into Mg-Al, Mg-RE and Mg-Al-Ti alloys makes the fine grain structures, the hardness of Mg-RE alloy is decreased. This strange behavior may be interpreted with existence of many fine pores in the alloy. The mechanical properties of composite Mg-9Al-6Ti with 3?O3 are higher than those of AZ91C. The present results demonstrate the potential of this new method for developing high performance magnesium alloys.     

搅拌工艺参数对半固态AZ91D镁合金流变性能的影响

通过自行设计制造的一套半固态镁合金机械搅拌装置，制备了AZ91D镁合金半固态浆料，研究了工艺参数对半固态镁合金流变性能的影响。结果表明，适合镁合金的半固态温度为560～570℃，其相对应的固相体积分数为41％～48％。在剪切速率为79．75s^-1、剪切时间为240s时就可使半固态镁合金获得良好的流变性能。