检索结果-南通市图书馆

Prediction and determination of both friction coefficient and forming force on sheet metal deep-drawing

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2002年第5期9卷 360-362页

作者： Junxiang yonglinkang 等 UniversityofShanghaiforScienceandTechnology Shanghai200093China UniversityofScienceandTechnologyBeijing Beijing100083China

On the basis of the criterion of no-wrinkle, the principle and method of prediction and determination of both friction coefficient and forming force on sheet metal deep-drawing are put forward, and proved it's expedience and practicability. They are suitable for assessment of lubricant properties. Friction coefficient and forming force are a function of material parameter, design parameter and process parameter, especially relative prevent wrinkle blank-holder force. Product of both friction coefficient and prevent wrinkle blank-holder force is only function of process parameter after determining material parameter and design parameter.

关键词： deep-drawing friction coefficient forming force prediction and determination

Microstructure and strengthening parameters of ultra-thin hot strip of low carbon steel

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2002年第5期9卷 356-359页

作者： HaoYu yonglinkang 等 MaterialScienceandEngineeringSchool UniversityofScienceandTechnologyBeijingBeijing100083China MaterialScienceandEngineeringSchool UniversityofScienceandTechnologyBeijingBeijin

The microstructure and precipitation mechanism of ultra-thin hotstrip produced by CSP technology were analyzed by electron backscattered diffraction(EBSD), H-800 transmission electronmicroscope(TEM)and thermodynamics theory. The EBSD results show thatthe finishing hot rolling microstructures are mixture ofrecrystallized and deformed austenite. After phase transformation,ferrite gra- ins embody substructures and dislocations that ledultra-thin hot strip high strength and relatively low elongationrate. TEM observations show that there are a lot of fine anddispersive precipitates in microstructure.

关键词： CSP EBSD microstructure precipitation

Ultrafine microstructure in microalloyed steel by a new thermomechnical process

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2002年第2期9卷 114-117页

作者： YuanliWang yonglinkang 等 DepartmentofMaterialsPhysicsandChemistry UniversityofScienceandTechnologyBeijingBeijing100083China DepartmentofMetalFOrming UniversityofScienceandTechnologyBeijingBeijing100083

Low carbon microalloyed steel containing 0.062 percent C, 2.34 percent Mn,0.044 percent Nb, 0.029 percent Ti, 0.032 percent V in mass fraction and small amount of B wasprepared in laboratory. Slabs of the steel were rolled into plates of 6mm in thickness followed byaccelerated cooling. The plates possess very high yield strength and reasonable ductility, and theyield ratio is about 0.8. Ultra-fine ferrite structure with micrometer dimension was observed in thesurface layer of the plates. Moreover, the effect of the finishing rolling temperature on the finalmicrostructure and formation mechanism of ultra-fine ferrite as well as the gamma->alphatransformation behavior of the steel was discussed.

关键词： microalloyed steel gamma->alpha transformation grain refinement microstructure boron-containing steel

Carbon Diffusion in Hot Strips of Low Carbon Steel Produced by CSP Line under Different Thermal Histories

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2005年第1期21卷 21-24页

作者： HaoYU HaoREN yonglinkang KeluWANG SchoolofMaterialsScienceandEngineering UniversityofScienceandTechnologyBeijingBeijing100083China LaiwuSteelGroupLTD. Laiwu271104China JinanIron&SteelGroupCo. Jinan250101China

Two experiments were carried out on the same compact strip production (CSP) line, which differs in that one of them experienced γ→α→γ thermal history. The differences in microstructure, precipitation, misorientation etc between two experiments were investigated by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron back-scattered diffraction (EBSD) and positron annihilation technique (PAT). The carbon concentration in matrix is more inhomogeneous in the experiment than that with γ→α→γ7 thermal history. The specific precipitation characteristic in the experiment without γ→α→γ thermal history is discussed on the basis of different carbon diffusion behavior and interaction between dislocation and excess carbon.

关键词： Compact strip production Microstructure Precipitation Carbon diffusion Dislocation

Lubrication in strip cold rolling process

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2004年第4期11卷 368-372页

作者： JianlinSun yonglinkang TianguoXiao JianzeWang MaterialsScienceandEngineeringSchool UniversityofScienceandTechnologyBeijingBeijing100083China

A lubrication model was developed for explaining how to form an oil film inthe deformation zone, predicting the film thickness and determining the characteristics oflubrication in the strip rolling process, combined with the knowledge of hydrodynamic lubricationand rolling theories. Various mineral oils with viscosities from 0.032 to 1.6 Pa-s were used toobtain different film thicknesses in the strip cold rolling. Results from the experiment andcalculation show that the oil film forming in hydrodynamic lubrication is up to the bit angle and ahigher rolling speed or a higher rolling oil viscosity. The mechanism of mechanical entrainmentalways affects the film thickness that increases with the rolling oil viscosity increasing or thereduction rate decreasing in rolling.

关键词： rolling strip lubrication film

Microstructural morphology of the semi-solid high carbon steel T12 before and after rheo-rolling

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2005年第2期12卷 139-142页

作者： JiguangLi yonglinkang AiminZhao YiSun ManCheng MaterialsScienceandEngineeringSchool UniversityofScienceandTechnologyBeijingBeijing100083China

The semi-solid high carbon steel T12 was rolled in a closed box groove under a certain condition by the rheo-rolling equipment, and the microstructural morphology of the semi-solid T12 before and after deformation was investigated by optical mi- croscope to analyze and summarize the microstructure evolution law of T12 deformed in semi-solid state. The experiment results show that the grain shape before deformation of the semi-solid T12 steel displays globule or ellipse by the electromagnetic stirring, the distribution of solid and liquid phases is homogeneous. But the microstructure of semi-solid product after rheo-rolling exhibits macrosegregation that the distribution of liquid and solid phases changes, the liquid phases divorce from the solid phases. In the transverse section, most of the solid phases get together in the center of the specimen, the liquid phases flow to the surface or the edge of the specimen, and the grains occur plastic deformation while reduction increased. In longitudinal section, the middle micro- structure of the specimen is more homogeneous than that at the head or tail, the head microstructure is similar to the tail and the size of the grains is not homogeneous.

关键词： semi-solid high carbon steel T12 rheo-rolling microstructural morphology

Metallurgical quality of CSP thin slabs

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2004年第2期11卷 106-109页

作者： DeguangZhou JieFu yonglinkang ZhongbingWang： JingLi ZhongboXu MetallurgicalandEcologicalEngineeringSchool.UniversityofScienceandTechnologyBeijing Beijing100083China GuangzhouZhujiangSteelCo.Ltd..Guangzhou510730 China

The casting structure, chemical composition segregation, dendrite arm space,inclusiona and during the CSP (compact strip production) rolling process were investigated. Theresults show that the CSP thin slab has a feature of uniform fine grains, more columnar crystals,less central porosity and segregation etc. There is no great difference in macrostructure betweenthe CSP thin slab and conventional slab; however, the fine dendrite structure of the CSP slab ismore uniform. Moreover, the central porosity and segregation are obviously improved after the firstpass; and the dendrite is bent along the rolling direction rather than broken into pieces. Smallinclusions with the diameter less than 10 mum in the CSP slab are dominantly consisted of aluminatesformed by Al deoxidation and Ca treatment and not floating out of the melt. The large sizeinclusions found in the continuous casting slab are very few.

关键词： CSP casting structure segregation dendrite arm space inclusion

Grain refinement of low carbon steel produced by CSP process

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2004年第2期11卷 133-137页

作者： XiangdongHuo DeluLiu YuanliWang NanjingChen yonglinkang JieFu MaterialsScienceandEngineeringSchool UniversityofScienceandTechnologyBeijing100083BeijingChina MetallurgicalandEcologicalEngineeringSchool UniversityofScienceandTechnologyBeijing100083BeijingChina

In comparison with conventional production for hot strips, compact strip production (CSP) brings about some new micro-structural phenomena. Investigations were carried out to clarify the grain refinement mechanism of low carbon steel strips produced by the EAF-CSP process. Samples, obtained from the same rolling stock during continuous rolling, were examined through SEM, TEM and XEDS. Thin slabs have a dominant columnar structure and the spacing of the secondary dendrite arms ranges from 90 to -125 μm. The average grain sizes for the central area of the samples from the 1st to 6th pass are 41.6, 25.2, 21.4, 20.2, 13.1, 6.7 μm, respectively. Large number of nanometer oxide and sulfide have been found in the low carbon steel produced by the CSP process. The grain refinement mechanism can be summarized as follows: finer solidification structure of the thin slab; austenite recrystalliza-tion at higher temperature and stain accumulation at lower temperature caused by the great reduction of single rolling pass during continuous rolling; nano-scaled precipitates of sulfide and oxide which drag grain boundaries of austenite or ferrite to prevent the grain coarsening.

关键词： low carbon steel hot strips CSP process microstructure evolution grain refinement

Microstructure evolution and precipitation behavior of low carbon steel hot strips produced by CSP

在线全文

学校读者我要写书评

暂无评论

Journal of University of Science and Technology Beijing 2004年第4期11卷 364-367页

作者： yonglinkang KeluWang HaoYu JieFu DeluLiu ZhongbingWang XuewenChen MaterialsScienceandEngineeringSchool UniversityofScienceandTechnologyBeijingBeijing100083China MetallurgicalandEcologicalEngineeringSchool UniversityofScienceandTechnologyBellingBelling1000153China GuangzhouZhujiangSteelCo.Ltd. Guangzhou510620China

The microstructures of low carbon steel before, during and after rollingdeformation of each stand were observed using optical microscope. The result showed that themicrostructures were very fine after six passes rolling deformation. The effect of the first standreduction on microstructure refinement was very distinct. During the rolling process, with theincrease of the accumulated strain, the microstructures would further refine, and the density ofdislocation would increase at the same time. In continuous casting thin slabs and each finishingstand, lots of observed precipitates were mainly A1_2O_3 and MnS along the grain boundaries or ingrains, which played an important role in the mechanical properties of the hot strips of low carbonsteel produced by CSP (compact strip production) technology.

关键词： CSP microstructure refinement precipitation mechanical property