降低高铬气门座缩松率的措施

本文对高铬气门座缩松形成的原因进行了分析，根据分析对其铸造工艺进行了改进，通过对铸造工艺改进的对比试验，提出了降低高铬气门座缩松率的控制措施。     

高合金活塞环的晶间缩松

高合金活塞环由于受其凝固特性的影响，极易产生晶间缩松，通过对成分、浇注温度进行控制．以及改进浇冒口能有效解决晶间缩松问题。     

JL4G15模具冒口系统改进

本文介绍了轿车活塞JL4G15德国铸造机模具系统的改进方案,通过开设顶冒口,以强冷代替补偿的方式,解决了该模具的销座厚大处剖面缩松问题,实践证明,改进以后的模具生产过程质量稳定,缩松废品率大大降低,改进效果明显。     

差速器壳体铸造工艺设计及改进

主要介绍工程机械差速器壳体铸件的工艺改进过程。此零件由于结构复杂,零件本身存在较多热节处,零件材料又是球墨铸铁,所以出现缩松的倾向较大。在生产过程中确实发现大量零件出现缩松,从而导致零件报废,给企业造成了较大的损失。通过工艺方案的逐渐改进,最终消除了缩松缺陷的过程,为相关零件的铸造提供了经验依据。     

如何减少合金铸铁油环心部缩松

1 引言 在单体合金油环机加工过程中,挖了油槽后,往往在油槽的心部可看到细小的孔洞,有时是一个,有时一连几个.这就是我们所说的心部缩松(宏观).缩松有宏观、微观两种,宏观缩松是用眼或放大镜可看到的小孔,多分布在铸件心部,微观缩松是分布在晶粒之间的微小孔洞,可遍及整个截面.环的心部缩松必然降低环的机械性能,这样可降低其使用性、安全性.因此对活塞环(油环)的心部缩松问题,一定要高度重视并加以控制,尽量减少或避免使油环产生心部缩松.     

改进浇冒系统 降低离合器盖废品率

通过对浇冒系统的改进，减少了铸件的缩松缺陷，降低了铸件废品率。     

天然气发动机铝硅合金活塞断裂机制研究

针对某型天然气发动机活塞断裂故障,运用化学成分分析、断面宏观和微观观察、能谱和金相分析等方法进行原因分析.结果表明活塞裂纹源处有缩孔、缩松等铸造缺陷.缩孔、缩松处O元素的重量百分比为30％以上,而且Mg元素偏析较为严重.铸造缺陷导致活塞在长期工作载荷下产生裂纹,最终引发活塞断裂故障.根据故障原因提出改进措施,并通过试验...     

320型船用柴油机活塞缺陷仿真分析研究

针对某柴油机厂在对传统活塞技术改进过程中出现的新的问题,采用计算机辅助设计(CAE)仿真和试验测试相结合方法,对带缺陷活塞的运行状态进行分析后得出:"多针孔状缺陷"会造成较严重的应力集中;"卵形缩松缺陷"对结构的应力水平影响不大;对冷却油腔尺寸做少量修改可以减小缩松缺陷.     

化学成分与孕育方法对球铁曲轴缩松缺陷的影响

阐述残留镁、稀土含量、碳当量、随流孕育和含量元素对球铁曲轴常见缺陷之一即缩松的影响:给出可消除或减少曲轴缩松废品的合适化学成分;同时指出应从铸造工艺设计考虑来减小随流孕育或添加含量元素所造成缩松增大倾向。     

铝黄铜流道式导向器浇注系统的工艺改进

通过将原顶注式浇注系统改进为底返式缝隙浇注系统，从而解决了铝黄铜ＺＨＡ１６７－５－２－２的氧化夹渣和气缩松的缺陷。     

Self-oriented iron oxide nanorod array thin film for photoelectrochemical hydrogen production

In this work, iron films were deposited on fluorine-tin-oxide coated glass substrate using radio frequency sputtering. Self-oriented iron oxide nanorod array thin films were obtained by anodizing the sputtered films. Anodization was carried out in an ethylene glycol solution containing 0.1 M NH₄F and various content of water. We studied the mechanism of anodization of iron thin films, and investigated the effects of some parameters on the properties of the iron oxide thin films.     

Studies on the role of iron oxide and copper chromite in solid propellant combustion

Iron oxide and copper chromite are the known burn rate enhancers used in a composite solid propellant. Lot of research has been carried out to understand the mechanism or location of action of the burn rate modifiers so as to better tailor the burning rate of a composite propellant. The literature is still very confusing in affirming the mechanism. Here, a systematic study has been carried out, by undertaking experiments at varying levels of combinations of the individual components (ammonium perchlorate, which is oxidizer and hydroxyl terminated poly butadiene, which is both fuel and binder) of composite solid propellant. Firstly, thermal gravimetric analysis, differential scanning calorimetry and burning rate measurements on the individual components are carried out to study the effect of iron oxide and copper chromite on the components themselves. It has been noticed that though both iron oxide and copper chromite are effective on ammonium perchlorate, iron oxide is slightly more effective than copper chromite. Also, copper chromite enhanced the binder melt flow, while iron oxide reduced it. These are followed-up by experiments on sandwich propellants, which give greater insight and enables better understanding of the behavior of iron oxide and copper chromite in composite propellants, as these are simple two-dimensional analogue of the composite solid propellants. Finally, experiments are carried out on the composite solid propellants to obtain a holistic understanding of the behavior/location of action of iron oxide and copper chromite in them. These studies are used to explain certain unexplained but observed phenomena, at the same time elucidating the location of action of these burn rate modifiers in composite solid propellant combustion. Based on these observations, it has been proposed that both iron oxide and copper chromite are primarily acting on the condensed phase. These studies are further complimented with experiments to analyze the thermal conductivity measurements of various propellant samples. This is pursued to understand the reason for the differences in burn rate pressure index for the composite propellants with iron oxide and with copper chromite. It has been understood from these studies that the thermal conductivity of a composite propellant is a key parameter, which affects the burn rate pressure index. Literature has never addressed it from this perspective.     

Steam co‐gasification of iron‐loaded biochar and low‐rank coal

Steam co‐gasification of iron catalyst‐loaded biochar, which was produced by the pyrolysis of woody biomass and Indonesian Adaro subbituminous coal at 800 °C, was carried out in this study. The main purpose of this work was to examine the effectiveness of an iron catalyst loaded on biochar for hydrogen (H₂) evolution. It was shown that the H₂ evolution for a mixed sample of iron‐loaded biochar (20 wt%) and Indonesian Adaro subbituminous coal increased by 20% compared with that for the coal sample with the same amount of iron catalyst and was approximately 1.5 that for the coal sample without the iron catalyst. This increase in the co‐gasification H₂ evolution was explained by the chemical form and crystallite size of the iron catalyst. Copyright © 2016 John Wiley & Sons, Ltd.     

如何提高船用柴油机机体球化率

针对船用柴油机机体球化率要求高的特点,从原材料的选用、球化处理、孕育处理、球墨铸铁的球化衰退控制等几方面就如何提高船用柴油机机体球化率进行了分析。指出：球墨铸铁的生产过程比较复杂,必须在各个环节按规范操作运行,才能保证铸件的质量。     

影响铁水脱硫过程粘渣物形成的因素分析

根据不同脱硫工艺条件下粘渣物成分的检验结果,探讨了熔渣的成分与性能、粘渣面工作温度与工作状况、脱硫工艺等因素对粘渣物形成的影响关系,分析了脱硫器具与脱硫铁水罐粘渣的危害,探明了铁水罐粘渣物清除困难的主要原因,指出了喷吹脱硫过程中熔渣与铁水喷溅对粘渣物铆钉状结合的促进作用.     

Iron pyrite FeS2 for flexible solar cells

We used the vacuum thermal evaporation technique to grow iron thin films on heated glass substrates. Thick fresh iron layers (1000–3000 Å) sulfurized under nitrogen flux were converted into iron pyrite FeS₂ phase identified by X-ray study.Reproducible 1–2 kω (10⁻² ω-cm) FeS₂ layers showed P type coductivity. Nevertheless, iron films previously oxidized showed N type behaviour when submitted to the same sulfurization process. Optical transmission measurements had been carried out on several thicknesses before and after layer conversion. The results confirmed the highly absorbing character of the pyrite FeS₂ and also the presence, in the explored spectral range (UV-Visible) of two competitive transitions: the first at 1.31 eV (indirect gap) abd the second at 1.45 eV (direct gap). Some interpretations are given concerning the origin of the opacity of the FeS₂ obtained from Fe films. Comparison is made with iron pyrite results obtained by spray pyrolysis as reported by some workers.     

储油罐内壁铁锈硫化及氧化反应

储罐内壁铁锈在低温有水的条件下与储罐中的硫化氢气体反应生成硫铁化物．硫铁化物的氧化放热是引起含硫油品储罐着火的主要原因．采用X-射线衍射仪鉴定铁锈成份,对铁锈主要成分室温下进行硫化及硫化产物的氧化实验,绘制硫化及硫化产物氧化反应温度-时间曲线,并鉴定分析硫化产物及硫化产物的氧化产物,研究对含硫储罐自燃的作用．结果表明,铁锈主要成分为Fe2O3和Fe3O4,室温硫化产物均为FeS,但FeS形状与其来源有关．形状、致密性不同,致使氧化自燃性不同．Fe2O3硫化产物比Fe3O4硫化产物的氧化自燃性高,对引发储罐自燃的危险性大．     

QT400-18球墨铸铁机体堆焊研究

对QT400-18球墨铸铁堆焊进行工艺试验研究及评定,试验包括检测QT400-18焊接接头的抗拉强度、硬度、宏观及金相分析等。研究结果表明:该堆焊工艺可行,且重复性和稳定性好;试验结果成功应用于球墨铸铁柴油机机体的修复。     

中国钢铁工业节能分析

2003年中国钢铁产量继续大幅攀升,能源等资源性缺口形成的制约因素日益突显。文章对中国钢铁用能总量、钢铁生产用主要能源品种及吨钢用能、工序用能等现状进行了客观地分析。指出目前在钢铁节能工作中仍存在诸如如何提高钢铁生产过程中副产煤气回收,提高能源利用率等问题,认为落实钢铁工业节能工作,应从企业整体出发,进行全流程综合考虑和系统节能,以减少投入,实现最大的节能效果。     

240柴油机机体裂损的分析与对策

对DF4型机车240柴油机铸焊机体的裂损部位及规律进行统计分析,并对焊接接头进行取样解剖,认为目前的240柴油机铸焊机体越来越不能满足当今运用要求,提出DF4各型机车采用整铸球墨机体代替铸焊组合机体的必要性和迫切性。