Surface turbulence in a physical model of a steel thin slab continuous caster

In the thin slab continuous casting (TSCC) of steel, the issue of optimum fluid flow is very important due to higher casting speeds and has direct influence on the formation of solidified shells and the quality of final products. In the current work, a full-scale physical mod-eling of a thin slab caster on the basis of dimensionless Reynolds and Froude similarity criteria was constructed. The flow pattern in the fun-nel shaped mold with a new tetra-furcated submerged entry nozzle (SEN) was investigated. To ...     

Mechanical performance and texture characteristic of an IF steel containing Nb and Ti by double cold rolling

Single cold rolling and double cold rolling were applied to hot rolled strips with different reduction ratios. The evolutions of {100},{111} and Goss face texture during double rolling were investigated by comparing the orientation distribution function(ODF) of the double rolled sample with that of the single rolled one. The double cold rolling texture is characterized by a higher γ-texture and a lower α-texture,and the {111}<112> component is improved remarkably. Based on the TEM observation and mechanical...     

Solidification and crystallization properties of CaO-SiO2-Na2O based mold fluxes

Crystallization properties play an important role in keeping a smooth running of continuous casting process and high sur-face quality of cast strands. To reduce fluorine pollution in slag, a new type of CaO-SiO2-Na2O (CSN) based mold flux was studied. The solidification and crystallization properties, including crystallization temperature, crystallization ratio and solidification minera-graphy, were measured, which were compared with the CaO-SiO2-CaF2 (GF) mold flux. The results show that the crystallization performance is equal to the high fluoride mold powder and CSN can be used for peritectic steel grades sensitive to longitudinal cracking in continuous casting.     

Corrosion behavior and mechanism of the automotive hot-dip galvanized steel with alkaline mud adhesion

The corrosion behavior and mechanism of hot-dip galvanized steel and interstitial-free (IF) substrate with alkaline mud adhesion were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS), and linear polarization. The results show that non-uniform corrosion occurs on the galvanized steel and IF substrate during 250 h with the mud adhesion. The corrosion products on the galvanized steel are very loose and porous, which are mainly ZnO, Zn5(OH...     

Characteristics of shell thickness in a slab continuous casting mold

The key to reduce shell breakout in the continuous casting process is to control shell thickness in the mold.A numerical simulation on the turbulent flow and heat transfer coupled with solidification in the slab mold using the volume of fluid (VOF) model and the enthalpy-porosity scheme was conducted and the emphasis was put upon the flow effect on the shell thickness profiles in longitudinal and transverse directions.The results show that the jet acts a stronger impingement on the shell of narrow face,which causes a zero-increase of shell thickness in a certain range near the impingement point.The thinnest shell on the slab cross-section locates primarily in the center of the narrow face,and secondly near the comer of the wide face.Nozzle optimization can obviously increase the shell thickness and make it more uniform.     

苯甲酰基苯基脲杀虫剂

取代苯基脲化合物的生物活性已经知道相当长一个时期了,很多众所周知的除草剂就属于这一类。而取代苯甲酰脲类化合物的杀虫活性只是在1970年前后才被Philips-Duphar公司所发现。在除草剂敌草腈结构活性研究过程中,把敌草腈与敌草隆相结合,得到1-(2,6-二氯苯甲酰基)-3-(3,4-二氯苯基)脲,代号为Du 19,111。此化合物没有显     

流变仪硫化时间与平板模压硫化时间的关系

橡胶是热的不良导体,因此较厚的橡胶模制品往往需要较长的硫化周期。据Hills报道,橡胶模压制品的硫化时间近似地与其厚度的平方成正比。对于较薄的模制品,橡胶在模腔内硫化时的温度能很迅速地达到外界所施加的值(例如模具内表面的温度)并在整个硫化周期内保持稳定,因而这种模制品的硫化比较均匀。对于较厚的模制品,情况就有所不同了,即:     

微生物杀虫剂

在美国、欧洲和世界上其他许多地方,一股从昆虫综合治理计划中减少化学杀虫剂使用的压力正在不断地增强。其主要原因是:害虫产生抗性,天敌消失和自然生态系统的破坏。公众担心由于化学杀虫剂的不断使用,残留的有害物质会进一步污染环境,尤其是对食品和水源。尽管这些忧虑常常并不正确,但是毫无疑问,这些公众意见促成了一系列限制农药应     

石油馏份裂解深度指标

引言烯烃生产的现代裂解反应器的最佳设计,要求各种反应动力学的精确计算机模型。不像轻烃那样,其裂解动力学已得到较好的了解;而复杂烃类原料(如石脑油、柴油)裂解的模拟进展,则受到限制。在开发用于这类原料的可靠裂解模型时,其中心的课题是确定原料的转化率或裂解深度问题。由于原料组分数多,且由于使用常规的检测方法不能测定原料中的大多数成分,因而原料转化率的直接确定无法考虑。在反应器出口物料中原料组分的定量分析也遇到同样困     

天然橡胶经济塑炼最佳新型塑解剂

提供一种以２，２＇－二苯甲酰胺基二苯基二硫化物（ＤＢＤ）为主体［１］．加上一种辅助促进剂的最佳新型塑解剂，替代以五氯硫酚（ＰＣＴＰ）为活性剂的工业用塑解剂Ｒｅｎａｃｉｔ＊７／ＷＧ。讨论了用这些塑解剂塑炼的天然橡胶的流变仪数据和硫化胶性能。