50Cr5MoV钢中非金属夹杂物行为

对采用"EBT→LF→VD"工艺路线生产50Cr5Mo V锻钢轧辊炼钢过程全氧和夹杂物进行了分析.结果表明:LF精炼后钢液中ω(T[O])平均为47×10-6,VD出站为14×10-6,中间包为15.5×10-6,铸坯为18×10-6.LF精炼初期,钢中夹杂物主要是不规则的Al2O3夹杂,96.75%的夹杂物尺寸小于10μm.LF精炼后,大量夹杂物为Ca O-Al2O3-Si O为主要成分的0~10μm复合氧化物夹杂.钢水向中间包转移过程中保护性浇注不理想,二次氧化严重导致钢水夹杂逐渐增多,主要为球形m Ca O·n Al2O3的复合夹杂物.铸坯中99.81%的夹杂物尺寸小于10μm,其中大部分为球形钙铝酸盐夹杂,还有少量球状硅铝酸钙复合夹杂.全过程的工艺优化是控制夹杂物(主要是氧化物)的合理途径,可确保实现50Cr5Mo V合金铸钢的冶炼.     

EAF-LF/VD-CC流程生产高压锅炉钢的工艺

天津钢管集团有限公司炼钢厂采用EAF全程泡沫渣埋弧操作、EBT出钢合金化、LF复合精炼渣精炼、VD处理后喂硅钙线、连铸全程保护浇铸生产高压锅炉钢12Cr1MoVG.通过系统取样、示踪剂追踪、综合分析等方法,对LF处理前后、中间包钢水和连铸坯中总氧(T[O])、显微夹杂及大型夹杂物的数量及变化情况进行了全面研究.结果表明,LF/VD精炼后钢液T[O]平均为15×10-6,中间包T[O]为17×10-6,铸坯为18×10-6～24×10-6;铸坯中的显微夹杂物数量是3.53mm-2,主要为球形钙铝酸盐、硅铝酸盐和铝酸盐与硫化物的复合夹杂,90%以上的夹杂物尺寸小于10μm;铸坯中大型夹杂物有铁铝硅酸盐、钙镁硅酸盐等.低倍组织均匀细致,表面质量良好,轧管各项技术指标均达到GB5310要求.     

气瓶钢精炼过程中的MgO·Al_2O_3夹杂物

研究了EAF-LF-VD-CC流程冶炼气瓶钢30CrMo时精炼过程中含MgO.Al2O3夹杂物的生成和转化,对夹杂物进行了三维分析观察.研究结果表明:LF精炼30min后夹杂物中Mg含量减小,Ca含量增加,MgO.Al2O3夹杂物消失.LF精炼后期Mg含量变化不大,Ca含量减小,未出现MgO.Al2O3夹杂物;VD精炼过程中夹杂物中的Mg含量增加,Ca含量变化不大,重新生成了MgO.Al2O3夹杂物;精炼过程中MgO.Al2O3夹杂物可以向复合夹杂物转变的,但为防止精炼后期MgO.Al2O3夹杂物重新生成必须保证钢液中具有一定的钙含量.     

BOF-LF-CC工艺生产50 CrVA弹簧钢洁净度研究

通过对国内某钢厂BOF-LF-CC工艺生产50CrVA弹簧钢进行全流程连续取样,综合分析了冶炼过程中总氧( T. O.)、N含量变化,非金属夹杂物的衍变规律,以及铸坯中大型夹杂物的特征.结果表明,LF精炼前T. O.和N的平均含量分别为106×10-6和13×10-6,铸坯中分别为15×10-6和39×10-6,LF过程脱氧效果明显;运输和浇注过程存在较明显的二次氧化现象,需要加强大包到中间包的保护浇注;铸坯中夹杂物主要为CaO-Al2 O3-MgO和CaO-Al2 O3-SiO2复合氧化物夹杂,其中Al2 O3含量(质量分数)较高,达到60%~70%,未得到低熔点夹杂物,可通过适当提高精炼渣碱度,或喂入适量钙线促使夹杂物充分转变为成分更加均匀的低熔点夹杂物;大型夹杂物以CaO和CaO-Al2 O3-SiO2-( MgO)球状氧化物为主,还存在一定比例的纯Al2 O3夹杂物,需要延长钢包弱搅拌时间使夹杂物充分上浮.     

冷镦钢非金属夹杂物行为

针对邢钢冶炼ML08Al冷镦钢的铁水预脱硫—顶底复吹转炉—LF精炼-连铸现行工艺与条件,经过系统取样、综合分析对冷镦钢生产过程中非金属夹杂物类型、来源、数量及分布进行了系统研究。研究表明:铸坯中T[O]的平均值为57.6×10-6;铸坯中显微夹杂物平均数量为41.4个/mm2,显微夹杂体积率为0.0485%,显微夹杂主要是复合硅酸盐夹杂和铝酸盐夹杂。铸坯中大型夹杂物的平均含量为30.7mg/10Kg,大型夹杂物也主要是复合硅酸盐夹杂和铝酸盐夹杂。夹杂物主要来源于脱氧产物、保护渣和覆盖剂,还有少量来自钢包、中间包内衬、喷涂料、喷补料和钢包打结料。     

超低氧车轮钢精炼过程非金属夹杂物的转变

研究了采用LD-LF-VD-CC工艺流程生产超低氧高速车轮钢时,精炼过程中夹杂物的生成与变化.实验在出钢时加入足够的Al进行终脱氧,LF精炼过程采用强脱氧、高碱度和强还原性精炼渣工艺,能使最终铸坯w(T.O)达到7×10-6,获得高洁净度的铸坯;而且在LF精炼过程中,夹杂物完成了Al2O3→MgO·Al2O3→CaO-MgO-Al2O3类复合夹杂物的转变,得到在炼钢温度下呈液态的复合氧化物夹杂,这些液态夹杂物通过碰撞、长大和上浮去除,残留于钢中的氧化物夹杂以较低熔点的CaO-MgO-Al2O3类复合夹杂形态存在,它们在热加工过程中可以发生稍许变形,能有效改善车轮钢的疲劳性能.     

高品质轴承钢LF--VD过程非金属夹杂物演变规律

对国内一钢厂EAF→LF→VD→CC工艺生产的高品质GCr15轴承钢进行系统取样,针对DS类非金属夹杂物随机性强的特点,利用能够进行大面积试样检测的ASPEX自动扫描电镜分析统计钢中非金属夹杂物的成分、尺寸、数量等信息。研究发现：GCr15轴承钢冶炼过程中非金属夹杂物主要为MgO- Al2 O3- CaO复合夹杂物和MnS,同时有少量的SiO2- Al2 O3和MgO-Al2 O3复合夹杂物;夹杂物尺寸主要集中在3~8μm,并有少量DS类夹杂物出现且尺寸范围波动很大,最大可以达70μm以上,形貌为圆形或近似圆形;VD有较强的去除夹杂物功能,经过VD真空精炼,夹杂物中CaO含量有增加趋势;吊包至铸坯过程,夹杂物成分向Al2 O3含量增多的区域移动,最终轴承钢铸坯中夹杂物成分位于高Al2 O3含量(≥80%),少量MgO (<20%)和低CaO(<5%)的区域;DS夹杂物的生成和去除具有较强的随机性。     

高品质GCr15轴承钢二次精炼过程中夹杂物的演变规律

采用FE-SEM/EDS研究了转炉流程生产的GCr15轴承钢LF、RH精炼过程中夹杂物的演变规律,分析了其演变机理。结果表明:钢中复合夹杂物的演变规律可归纳为:Al2O3→MgO·Al2O3→(CaO-MgO-Al2O3-(CaS))复合氧化物夹杂和Al2O3→(Al2O3-MnS)→(Al2O3-MnS-Ti(C,N))复合氧硫碳氮物夹杂2种方式。LF精炼过程脱硫作用明显,钢中的硫化物夹杂数量大幅减少。LF精炼初期钢中主要是MnS、Al2O3、TiN的单相夹杂物。LF精炼结束后钢中的夹杂物演变为Al2O3为核心外包氧化物及MnS、TiN、Ti(C,N)、CaS的复合夹杂物。精炼渣中的CaO和耐火材料中的MgO经还原后与钢中溶解氧反应导致LF精炼结束时D类夹杂物增加。RH及软吹处理进一步强化了去除钢中的硫化物,但D类及其与A、T类复合的夹杂物含量增加。在LF阶段,夹杂物尺寸主要集中在1~3μm范围内,到RH阶段,夹杂物尺寸则主要集中分布在小于1μm的粒度范围。最大夹杂物尺寸由10.79μm降到5.68μm,单位面积夹杂个数由372个/mm2降到258个/mm2。RH及软吹处理有效地降低了钢中大于3μm的夹杂物。     

精炼渣成分与轴承钢夹杂物类型关系热力学分析

针对轴承钢中钙铝酸盐大型夹杂物的控制问题,通过计算GCr15轴承钢中尖晶石MgO·Al2 O3、钙的铝酸盐CaO·6Al2 O3夹杂物生成热力学,分析精炼渣成分与夹杂物类型之间的定量关系.结果表明：当钢水中含有质量分数0.10×10-6的溶解钙[Ca]时,只要溶解镁[Mg]质量分数小于10×10-6,MgO·Al2O3就会被[Ca]还原成 CaO·6Al2O3;当精炼渣碱度为7.04,(MgO)质量分数为1.38%时,钢水中溶解[Mg]质量分数比临界[Mg]质量分数低56%,夹杂物以尺寸大于10μm的CaO-Al2O3系复合夹杂为主;当精炼渣碱度为3.75,(MgO)质量分数3.14%时,钢水中溶解[Mg]质量分数比临界[Mg]质量分数低14%,夹杂物以尺寸小于8μm的MnS包裹MgO·Al2 O3复合夹杂为主;当精炼渣钙铝比C/A为1.8~2.0时,控制精炼渣碱度R为4.5~5.5,(MgO)质量分数为3%~5%,即能使钢中MgO·Al2O3保持稳定而不转变为CaO·6Al2O3.     

硬线钢夹杂物行为

针对唐钢硬线钢冶炼的现行工艺与条件,经过系统取样、综合分析对硬线钢生产过程中非金属夹杂物类型、来源、数量及分布进行了系统研究。研究表明:铸坯总体积率为0.0625%。显微夹杂的数量平均值为16.66个/mm2,面积百分比为0.018%。铸坯中的显微夹杂是硫化物夹杂、硅酸盐夹杂物、氧化铝夹杂物。铸坯中大型夹杂物的平均值为31.5mg/10Kg。铸坯中主要的大型夹杂物是硅酸盐和铝酸盐,其次还包括少量的硫化物。铸坯中夹杂物主要来源于脱氧产物、保护渣和覆盖剂的卷入。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with