基体钢的组织与性能及其在冷变形模具上的应用

本文试验研究了国产新型基体钢6Cr4Mo3Ni2WV(简称CG-2)的热处理工艺与组织、性能的关系及其在冷镦十字槽螺钉冲头和冷挤压活塞肖冲头上的使用寿命。研究结果表明:新钢种在1120～1140℃淬火,560℃两次回火与6—5—4—2高速钢在淬火三次回火条件下相比,硬度、静弯强度、抗压强度、抗压屈服强度和小能量多次冲击抗力,前者均略逊于后者,然而挠度和无缺口一次冲击值,前者显著地优于后者。文中分析讨论了二者性能差异的组织因素和合金元素的影响。试验也证实了对脆性状态的工模具材料的多次冲击抗力的规律与对机械零件适用的多次冲击抗力的基本结论是一致的,即冲击能量低时,多冲寿命取决于强度,而冲击能量高时,多冲寿命取决于韧性。新钢种用于冷镦十字槽螺钉冲头,一次寿命在8.5～9.3万件,打破了国內标准行业的最高记录。然而,用于活塞肖冷挤压冲头,却未显示出其优越性。根据试验结果,分析讨论了上述两种冲头矛盾的特殊性与机械性能的关系。最后,本文对新钢种的进一步试验研究的合金化方向,组织形态与性能的关系等方面,提出了若干建议。     

冷镦模在热处理时的变形及使用寿命

本研究工作中表明：在热处理时,金属的原始组织和加热及冷却方法对冷镦模孔的交形及其使用寿命有巨大的影响。 经调质处理后。冷镦模加热到８２０℃（快速加热）,然后放在夹具上在水中用水喷内孔;经过这样处理以后冷镦模的内孔变形甚小,而其使用寿命可增加３到５倍。     

60Si2Mn小型冷冲头热处理工艺的改进

为提高小型冷冲头的使用寿命,以60Si2Mn为材料,经亚温加热、局部淬火 低温回火等热处理工艺处理,设计制造了用于加工标准件的小型冷冲头。实际冲裁生产结果表明,冷冲头的使用寿命有了大幅提高,冲裁次数可达50000~60000次。     

镁-稀土系ZE10镁合金板料的热拉深成形性能

通过对不同温度、冲头速率、压边方式、压边力以及润滑条件下板料的变形状态及冲压力-冲压行程曲线的研究,考察不同成形条件对ZE10镁合金板料成形性能的影响.在成形过程中,采用加热元件与热电偶连接的方式对凹模与冲头进行温度控制;通过对弹簧压下量的控制分别施加固定压边力与渐变压边力.结果表明,当凹模温度为250-300℃、冲头温度为(60±5)℃、冲头速率为(20±5)mm/min时,采用浮动压边方式,压边力从2 kN逐渐增大到10 kN,并以80%气缸油 20%石墨作为润滑剂,ZE10镁合金板料具有较好的成形性能,其极限拉深比可达2.8.     

大口径阀门阀体多向模锻成形的模具优化设计

多向模锻是现阶段大口径阀门阀体生产工艺。多向模锻冲头存在过早断裂以及表面压溃变形等问题,冲头使用寿命较短。锻件金属流动的不均匀性是导致冲头受力偏载发生断裂的首要原因,冲头材料热强性较低导致表面发生压溃变形。该文通过优化模具设计改善锻件金属流动趋势,改变冲头与压机的连接方式以减少冲头根部应力集中,采用FGH96高温合金作为锻压冲头材料,提高冲头的高温变形抗力。工艺分析及实验表明:优化模具圆角,水平冲头表面采用光滑化设计,可有效降低冲头连接部位应力集中水平,防止冲头在生产中发生断裂;采用FGH96材料制造的水平冲头在连续生产时,冲头应力水平低于屈服强度,冲头未发生压溃现象。所设计的锻压3吋(7.62cm)旋塞阀用压机水平冲头,经现场实验,其冲压次数达到100件,未发生断裂及表面压溃,冲头的使用寿命有较大幅度延长。     

加热条件和轧制过程温度对35K盘条组织的影响

盘条表层的魏氏组织是35K冷墩盘条冷镦开裂的主要原因.为控制表层魏氏组织,首先在实验室模拟了加热炉的加热时间和均热温度,然后根据实验室的研究结果在工厂进行了不同轧制过程温度的试验.试验结果表明:当在加热时间80～90min、均热温度1160～1230℃、终轧温度820～840℃和吐丝温度800～820℃的条件下,所获得的盘条组织均匀、表层魏氏组织小于1级,有效地防止了冷镦开裂.     

真空复合热处理提高冷镦模具使用寿命的研究

本文对标准件行业应用量多面广的冷镦凹摸的服役条件及失效形式进行了研究分析后,指出该类模具要求高的耐磨性与足够的冲击韧性以及400—500℃的红硬性。尔后,在高温回火过程同时复合真空氧氮化,获得了理想的组织与优异的性能,并具有优质、高效、节能、低温、微变形、无公害等优点,使××厂的冷镦凹模使用寿命提高1—3倍。取得了明显的经济效益。     

移圈针扩圈片安装过程的应力场模拟

为了解决移圈针上扩圈片安装过程中出现的冲头崩裂和安装不牢固问题,采用有限元软件ABAQUS对不同倒角半径的冲头在扩圈片安装过程中的应力应变场,及扩圈片和其安装槽之间接触力的影响规律进行模拟和分析.结果表明,随着倒角半径的增大,冲头上所受的应力呈现整体下降的趋势,扩圈片与其安装槽的接触应力也在减小.经比较分析得知,最佳的倒角半径为0.11mm,此时,既能保证冲头拥有较长的使用寿命,又能保证扩圈片的安装牢固度.将模拟结果应用于移圈针的实际生产,单枚冲头的使用寿命与之前相比提高了5倍,且扩圈片的安装牢固率达到了100%.     

形变热处理对GCr15钢机械性能的影响

对GCr15钢辅以适当的热处理工艺,可以得到良好的强度、硬度、韧性、抗疲劳性能与尺寸稳定性,对于在恶劣环境条件下(冲击、挤压、磨损)使用的挤压冲头,其成本与使用寿命的比值仍偏高,采用形变热处理工艺后,其抗拉强度、冲击韧性、洛氏硬度等性能优于普通热处理工艺,从而使挤压冲头使用寿命得到大幅度提高     

生物膜法处理恶臭气体H_2S的研究

采用 PVC弹性立体填料进行了好氧生物法脱硫的研究。结果表明 :生物挂膜速度快 ,驯化时间短 ,抗冲击负荷能力较强 ,在空速为 10 0～ 2 0 0 h- 1,喷淋水量为 10 0 0～15 0 0 L/( m3·h) ,H2 S质量浓度 <12 0 0 mg/m3时 ,脱硫率达 90 %以上。该法较其他填料孔隙率高 ,比表面积大 ,且压力损失小 ,使用寿命长 ,但吸水性较差。     

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