Antibacterial Characteristics of ZnO-CeO2 Nano-Powder Prepared by Laser Vapor Condensation

Microbialpollutionandcontaminationbymicroor ganismshaveproducedvarioustroublesinindustryandothervitalfields ,suchasdegradationandinfec tion .Thenewpasteurizationandantibacterialtech niqueshavebeendemandedandstudied[1] .Inrecentyears ,therareearthmetaloxid…     

异步轧制对二次再结晶取向硅钢磁性能的影响

研究了异步轧制条件下不同厚度的二次再结晶取向硅钢成品的磁性能的变化,找到了硅钢磁性能与成品厚度和异步速比之间的关系.     

退火炉的节能技术改造

介绍了对退火炉料架、装炉方式及退火工艺的改进，结果在不改变现有工艺条件的情况下，达到了增加装炉量，提高生产效率，节能降耗的目的。     

Physical Modelling of Transport Phenomena in a Delta‐shaped,Four‐strand Tundish with Flow Modifiers

Experiments were conducted in a full‐scale physical model of a delta‐shaped, four‐strand tundish to study the effect of flow modifiers on tundish performance. Two different types of flow modifiers were studied; an existing flow‐modifier and a turbulence‐inhibitor. Their effects were quantified by measuring residence times of fluid in the tundish and residual ratios of inclusions. Although the Turbulence‐Inhibitor appeared to be more effective in guiding flows than the flow‐modifier, the latter gave the longer average residence times and smaller residence time differences between the inner and outer nozzles, which resulted in a higher residual ratio of inclusions.     

Theoretical and Experimental Damage Prediction in Cold and Semi‐Hot Bulk Forming of Ductile Steels

Bulk forging is among the most important manufacturing methods in metal forming, due to its wide applicability from some ounces to several tons of steel in a high diversity of shapes and forming conditions. Economical constraints demand for further optimisation and cost‐effective production. This requires the application of suitable finite elements simulation software, in order to support the already digitalised construction processes. Ductile damage is one of the most severe problems to arise during the production sequences, not only in cold but also in semi‐hot forging operations. Mathematical approaches exist for the modelling and simulation of ductile fracture in steel. In this paper some widespread used damage models are introduced and discussed. Their damage prediction quality has been verified by experiments, the tensile test and the collar specimen upsetting with several different steels under cold and semi‐hot forging conditions. The methods for the experimental fracture detection are introduced as well. In cold forging the passive ultrasonic testing with integrated statistical filtering algorithms is used. As this method is not applicable to semi‐hot forging experiments, optical fracture detection by means of a high‐speed camera is used instead. A very interesting material behaviour of the steels tested has been identified in the semi‐hot upsetting of collar specimen. For every steel a distinct temperature crossover interval exists, in which the forging process abruptly changes from damaged to undamaged state. This interval amounts to some degrees Celsius only for each of the seven materials investigated. Among the damage models proposed, the Model of Effective Stresses by Lemaitre is chosen for the application to a cold and a semi‐hot forging operation. These industrial processes of an axle end (cold) and a journal bearing (semi‐hot) are susceptible to damage for reasons to be discussed in this paper. It will be shown that the internal fracture of the axle end (chevrons) and the surface fissures of the journal bearing can be predicted with high accuracy. Moreover, the application of the damage model in the finite element software MSC.SuperForm 2004 offers a promising approach for process optimisation. Several possibilities could be tested for their suitability of reducing the calculated damage: geometry variation of the forming tools, process annealing, different materials. The use of damage models in finite element simulation can be regarded as a further step towards an optimal process design.     

Effect of Hot Band Annealing on Magnetic Properties in 3% Si Grain‐oriented Electrical Steels

Hot band annealing is known to be a prerequisite for good magnetic properties irrespective of manufacturing methods in grain‐oriented Fe‐3 wt.% Si electrical steels. In this study, the effects of hot band annealing on magnetic properties were investigated in 3% grain‐oriented electrical steels of low soluble AI contents and one‐stage cold rolling. Microstructure and precipitate distribution were compared with hot band annealing conditions. Secondary recrystallization behaviour with hot band annealing condition was also discussed.     

Recent Progress on Non‐oriented Silicon Steel

Control of crystalline orientation and consequent enhancement of magnetic properties are important for decreasing core loss of non‐oriented silicon steel as well as grain‐oriented silicon steel. Through the development of special process techniques to produce clean refined steel, it is now possible to use any element to improve the crystalline texture control of steel without producing harmful effects. Utilization of these effects have actually lowered the core loss and raised the magnetic flux density of the products, and a product series of high‐efficiency non‐oriented silicon steel has been developed. Recently, demand has grown for non‐oriented silicon steel with particular properties, such as lower core loss at high frequencies or high strength, as high‐speed motors have progressed in regard to high efficiency and miniaturization. In response to this trend, non‐oriented thin gauge silicon steel with a thickness of 0.20 and 0.15mm and high strength non‐oriented thin gauge silicon steel with the same thickness but a yield strength of more than 570MPa and 780MPa have been developed.     

Model of Precipitation Kinetics Induced by Strain for Microalloyed Steels

In microalloyed steels, static recrystallisation is temporarily inhibited by precipitation which is occurring at the same time. A high number of microalloyed steels containing various combinations of carbon, nitrogen and precipitate forming elements like V, Nb and Ti were recrystallised at different temperatures and strain rates. From these results recrystallisation‐precipitation–time‐temperature (RPTT) diagrams were established. The influence of grain size and strain rate on the RPTT diagrams was studied. The precipitation kinetics were mathematically described for isothermal conditions and converted to cooling conditions, which enables an application to hot rolling. Under cooling conditions, completion of recrystallisation is prevented, especially for Nb alloyed steels.     

Experimental Study on Soluble Oxygen in Hot Metal Pretreatment

The change law of oxygen activity was studied by using Fe₂O₃‐CaO‐CaF₂ and Na₂CO₃/Na₂SO₄ fluxes under laboratory conditions. At the same time, the range of oxygen activity which is in favour of removing phosphorus and sulphur simultaneously was also investigated. The results showed that the oxygen activity in the iron melt during de‐phosphorization can reach up to 5.91×10^?6~10.03×10^?6 in about 5 min and then only varies within a narrow range. A final phosphorus content of 0.008% and a final sulphur content of 0.003% can be obtained if the oxygen activity is controlled within the range of 4.5×10^?6~8.0×10^?6.     

CVI法制备2D C/C复合材料

采用预制体直接加热模式的CVI工艺在25．5h内制备出24mm厚的2DC／C复合材料，分析了该工艺快速致密的机理，并观察和测试了材料的微观结构和力学性能。结果表明：该工艺能在较短时间内制备出结构均匀、力学性能较好的C／C复合材料，是一种制备C／C复合材料较为理想的工艺。其快速致密机理可认为：自由基磁吸引作用、自由基电沉积作用和自由基脱氢聚合三个方面。