吹氩宽厚板坯连铸结晶器内液面波动行为的水模型研究

基于相似理论,利用物理模拟研究了吹氩条件下宽厚板坯结晶器内的液面波动行为,考察了吹气量、水口侧孔倾角及水口浸入深度对结晶器内液面波动行为的影响.结果表明,结晶器吹氩后,各气量下液面平均波高均增加了1.2倍以上;结晶器内液面平均波高随吹气量的增加先增大后减小;随水口侧孔倾角及浸入深度的增大,液面平均波高均先减小后增大.从实验条件下得到的控制液面波动的最佳工艺参数为4 L/min的吹气量,-15°的水口侧孔倾角,140 mm的水口浸入深度.     

连铸用耐火材料的技术发展

介绍了连铸用钢包和中间包衬用耐火材料，整体塞棒、浸入式水口和长水口以及密封材料、保护渣等的最新发展     

Steelcasting and intermediate ladles for equipment for the continuous casting of steel

Conclusions The life of linings in large ladles depends on the grade of steel, the amount, chemical composition and consistency of the slag.The intermediate ladle made in the factory ensures reliable operation during the casting of metal by the continuous steel casting operation.Heating the intermediate ladle to 1100–1200°C by means of compact burners, working on coke gas, and new designs for cooled stoppers and stopper devices greatly reduces slab loss.In the process of evaluating the casting of transformer steel the loss due to nonmetallic inclusions was greatly reduced, but not completely eliminated.Further work must be done to explain the causes of the formation of slag inclusions and methods of handling the problem.     

Effects of partial and total methane flows on the yield and structural characteristics of MWCNTs produced by CVD

Multi-walled carbon nanotubes (MWCNTs) were produced in a chemical vapor deposition (CVD) process employing methane and argon as hydrocarbon and carrier gas over supported sol-gel Co-Mo/MgO catalysts. A detailed study about the influence of the gas flow of both hydrocarbon and carrier gas on carbon yield, morphology, structure and graphitization degree is presented. Methane partial pressure, methane total flow rate, as well as the flow ratios of methane to argon and methane to hydrogen (reducing gas) were the parameters systematically varied. The results reveal that high MWCNT yields in the produced materials are strongly related to the methane partial pressure and the methane total flow, while a high degree of graphitization is more closely linked to the use of argon gas as inert atmosphere.     

吹氩板坯连铸结晶器内夹杂物去除的数值模拟

针对吹氩板坯连铸结晶器内非金属夹杂物去除问题,采用准单相模型和离散相模型描述了水-空气-夹杂模拟物体系和钢液-氩气-夹杂物体系的粒子行为和去除效率.结果表明,吹氩有利于夹杂物上浮去除,同一气量(6.0L/min)下夹杂物在拉速1.3m/min时去除率最低.同一拉速(1.2m/min)下存在临界气量9.0L/min,小于临界气量,吹氩可增加夹杂物上浮率,减小进入铸坯率;大于临界气量,夹杂物上浮率减少,进入铸坯率增大.准单相模型和离散相模型能较好地模拟夹杂物在气液两相中的运动和去除.     

Al2O3-C质整体塞棒在浇铸钙处理钢中的应用

分析了Al2O3-C质整体塞棒在钙处理钢浇铸过程中的侵蚀机制和其他一些重要影响因素,针对Al2O3-C质整体塞棒的特性,从炼钢的工艺改进、设备保障、优化过程控制和耐火材料材质优化等方面采取了相应措施,并提出了改进意见,使Al2O3-C质整体塞棒在钙处理钢的使用寿命不断提升,达到了比较满意的效果。     

Comparison of a-C:H films deposited from methane–argon and acetylene–argon mixtures by electron cyclotron resonance–chemical vapor deposition discharges

Hydrogenated amorphous carbon (a-C:H) films are deposited from methane–argon and acetylene–argon gas mixtures in a microwave electron cyclotron resonance plasma reactor. The films deposited with the two different gas mixtures under similar input parameter conditions have substantially different properties, including deposition rate, mass density, optical absorption coefficient, refractive index, optical bandgap and hydrogen content. The deposition parameters varied include rf-induced dc substrate bias voltage (0 to −60 V), pressure (1–5 mTorr) and argon/hydrocarbon gas flow ratio (0–1.0). The discharge properties of the two different gas mixtures, including electron temperature, ion saturation current, and residual gas composition of the exit gas flow, are measured to help explain the different deposition results from the two different gas mixtures. The use of lower pressures is found to be critical for obtaining denser, lower hydrogen content films from acetylene. For the methane-deposited films the addition of argon to the discharge increased the film's mass density and lowered the hydrogen content. In both methane- and acetylene-based deposition processes the rf-induced bias is also a critical determining factor of film properties.     

Structure and Material Design of High Performance Functional Refractories for High-speed Continuous Casting

Functional refractories,including submerged entry nozzle ( SEN) ,ladle shroud and monolithic stopper, are the key refractories for continuous casting. Driven by the demand of high-speed continuous casting,traditional functional refractories fail to meet the needs of long span life,and high performance functional refractories for continuous casting are increasingly required. Through structure and material design,the performance of functional refractories is significantly improved. In this paper,some research advances on functional refractories for continuous casting were mentioned. Through numerical modeling and hot simulation,the service life of non-preheating ladle shroud was increased from 8 h to more than 12 h. Through the water modeling,the flow patterns in the mold were significantly improved and through hot simulation and material design,the service life and reliability of SEN were also significantly improved.     

Analysis on Abnormity Erosion of Monolithic Stopper Slag Line

Monolithic stoppers play a very important role in continuous casting( short for CC). Sometimes,the stopper slag line is seriously eroded and broken,CC has to pause. The research shows that there are three main reasons which bring severe erosion of monolithic stopper slag line. Firstly,much Fe_2O_3 and MnO in slag react with carbon( C) in the stopper,C is gradually eroded and erosion resistance of the stopper greatly weakens. Secondly,F increase in tundish covering flux will quicken erosion of the stopper slag line. Thirdly, High LOI of tundish covering flux also makes erosion of the stopper slag line speed up. On one hand,CaCO_3 in tundish covering flux decomposes and brings CO_2; on the other hand,minerals with water in tundish covering flux decompose at high temperatures and bring water vapor.Then CO_2 and water vapor react with C in the stopper,C is gradually eroded,aggravating the erosion.     

Dynamics of the flow of a dense fluid in narrow pores

A new approach was employed for the theoretical study of a dense fluid flow (gas and liquid) in narrow pores. Calculations were made on the basis of the Navier-Stokes equations. The transfer coefficients and the equations of state were derived within the framework of the simplest molecular model, namely, the lattice gas model. This model takes into account the volume of molecules and their interaction with one another. The transfer coefficients and the equations of state prove to be dependent on the local values of the fluid density and temperature. A study was performed into the dynamic modes of flow of a monoatomic gas (argon) in slitlike pores of various widths at a given pressure drop across the pore ends. It was shown that, at low densities, there is a high anisotropy of the flow owing to the attraction of argon atoms to the pore walls, which gives rise to a strong dependence of the local viscosity on the distance from the pore wall and to the film flow. An investigation was carried out into the dynamics of the interaction between the gas and liquid zones, which is accompanied by the breakdown of the interface.     

石膏模具的改性研究

本文介绍了以苯丙乳液为改性剂对。一石膏进行改性研究的情况,通过研究选出了改性剂的品种及最佳加入量,所进行的洗面器中压注浆试验证明,改性后的石膏模可用于卫生瓷中压注浆成形工艺中。     

药用胶塞结构与模具设计研究

药用胶塞属于特种橡胶制品亦属于药用包装材料,它的最大特点是市场需求量巨大,要求特殊,国内各类胶塞年总生产量在500-600亿只,本文通过对胶塞结构介绍,探讨了关于胶塞模具设计及应注意的问题,介绍了胶塞模具的结构。     

Conceptual design of a novel hydrodynamic cavitation reactor

Hydrodynamic cavitation has been increasingly used as a substitute to conventional acoustic (or ultrasonic) cavitation for process intensification owing to its easy and efficient operation. In this paper, we have put forth conceptual design of a new kind of hydrodynamic cavitation reactor that uses a converging-diverging nozzle for generating pressure variation required for driving radial motion of cavitation bubbles. Moreover, the reactor uses externally introduced bubbles of a suitable gas (argon or air) for cavitation nucleation. This design differs from earlier designs used by researchers where an orifice plate is used for creating cavitating flow. The new design offers a good control over two crucial parameters that affect the cavitation intensity produced, viz. rate of nucleation and nature of pressure variation driving bubble motion. Using numerical simulations of bubble dynamics and associated heat and mass transfer, trends in cavitation intensity produced in the reactor are assessed with varying design parameters. The results of simulation show that the externally introduced bubbles undergo transient motion in the flow through the nozzle generating moderate cavitation intensity. On the basis of results of simulation, some recommendations have been made for the effective design and scale up of the new kind of hydrodynamic cavitation reactors using concept introduced in this paper.     

基于Fluent仿真的流延辊流道设计研究

在流延薄膜的生产过程中,熔融聚合物从模头挤出后在流延辊上冷却的过程对流延薄膜的质量起着至关重要的作用。选取双进双出的矩形截面螺旋形流道的流延辊为研究对象,在利用F luent对其换热过程进行数值模拟仿真的基础上,分析研究流延辊的流道结构和尺寸参数对流延辊换热能力的影响,所得结果可为合理设计流延辊的结构、优化流延辊的参数提供指导。     

Increasing wear resistance of stoppers for 140-ton steel-casting ladles

Conclusions Among the principal reasons for partial or substantial leaking of the metal stream are the following: burning away of the stopper, breaking off of the spherical part of the head, wear and tear of the head and sleeve bricks and opening up of the seams through deformation of the rod.The stoppers burn away on account of a great deal of wear and tear in the pipes, erosion of the seams, formation of cracks in the pipes and head and deformation of the stopper on account of the rod becoming too hot.The amount of slag in the ladle is one of the main factors for corrosion wear in stopper pipes. The aggressive action in the slag increases as the temperature of the metal and casting time are increased.Breaking off of the spherical part of the head during the first stopper opening due to the formation of skull between the stopper saddle and head can be avoided by using a graphite filling.Insulation of the stopper rod reduces the temperature during casting by 150–300°. The use of good quality mortar in assembling stoppers reduces the erosion of seams, while the use of a high-alumina putty prevents wear in the pipes.     

Binder Burnout from Layers of Alumina Ceramics Under Centrifugal Force

The effect of centrifugal force on the delamination of layered green body during binder burnout has been studied in terms of internal gas pressure resulting from gas flow kinetics in porous media. Here, a sheet of nano-particle of γ-alumina was prepared by tape casting using polyvinyl butyral (PVB, binder) and dibutyl phthalate (DBP, plasticizer). Because of the fine pore structure (average pore size of 25 nm), molecular flow kinetics was applied to estimate internal pressure arising from evolved gases. Assuming that delamination is related to internal pressure, the interfacial strength of the layer was estimated. This strength was modified by applying a compressive pressure controlled by a centrifugal force. Because of the increased interfacial strength, delamination was suppressed, even during rapid heating. The compressive pressure required increased proportionally with increasing heating rate, a tendency that agreed with the expectation based on the gas flow kinetics in porous media.     

Some aspects of operating bllowing assemblies of 350-ton steel casting ladles of OAO ZSMK under conditions of processing technology for metal preparation in a furnace-ladle unit

Measures have been developed OAO ZSMK for bottom blowing of metal in steel casting ladles of acid converter workshop No. 2, including provision of a stable argon pressure for blowing of bottom lances in furnace-ladle units (FLU), daily inspection of argon and nitrogen supply pipelines in metal finishing units (MFU) and FLU, replacement of easily-detachable joints in steel casting ladles and refractory tracts, shortening of the duration of melt processing in FLU to 40 min. Industrial tests of blowing assemblies of different construction are performed. Analysis of test results makes it possible to obtain the most stable and efficient operating indices in processing metal with argon in a FLU and to select a producer for refractory production taking account of the reliability and precision during its installation. __________ Translated from Novye Ogneupory, No. 9, pp. 7–10, September 2007.     

Production and use of low-fired stopper tubes

Conclusions Fireclay stopper tubes made by semidry pressing and fired at 800–900° C are suitable for service in steel casting ladles in the open-hearth departments of NTMK. Compared with ordinary low-fired stopper tubes they are more spalling resistant and less thermal conducting.The use of low-fired stopper tubes is economical owing to the reduction in loss and fuel consumption in firing.Translated from Ogneupory, No. 5, pp. 8–10, May 1967.     

鱼盘的压力注浆成形

叙述了鱼盘压力注浆成形的过程和结果，列出了对石膏模型的要求。     

高压注浆成形技术

叙述了高压注浆模具及设备的发展历程和性能，介绍了高压注浆设备的操作方法和注浆泥料性能的调整措施。