烫斗手柄注射模设计

分析了烫斗手柄注射模的设计要点,着重对该模的二次侧抽芯方法进行探究,巧妙地解决了塑件侧凹中有侧孔的二次侧向抽芯的关键问题,达到优化模具结构设计,提高经济效益的目的。     

关于铸铁氧化性能参数的讨论

在分析讨论铸铁性能参数的基础上,对常用的氧化参数——氧化增重及氧化层厚度的实验方法作了一些改进.经反复验证,认为采用改进的实验方法评价铸铁的氧化性能,可以得到比较精确的结果.最后还提出了新的氧化参数——氧化蚀掉深度的实验方法以及抗氧化性指标——氧化参数倒数的概念.     

Influence of Oxygen Dissociation on the Oxidation of Iron

Kinetics of the oxidation of iron in fluxes of atomic and molecular oxygen have been studied over a wide temperature range from 573 to 1273 K. The influence of oxygen pre-dissociation on the oxidation rate was found negligible at 573–1073 K. At temperatures above 1073 K, when only FeO is formed, the rate of iron oxidation in atomic oxygen is substantially higher than that in molecular oxygen. Decarburization occurs during the first stage of oxidation of iron containing carbon. The rate of carbon elimination in atomic oxygen exceeds that in molecular oxygen due to the higher chemical potential of atomic gas.     

Oxidation Of Iron at Room Temperature

Abstract

Oxidation of (001), (011), (112)monocrystalline, and of large-grained and small-grained polycrystalline, pure Iron has been studied in laboratory air at room temperature at 44–46% relative humidity for 120 days by gravimetric methods, electron diffraction and electron microscopy. After the initial oxide growth, no significant oxidation occurred for about 20–30 days, when oxidation re-commenced slowly and became rapid, until after 90 days the rate became irregular and was associated with decreasing epitaxy. The rate of oxidation in decreasing order was(001), large grained, small grained, (011) and (112). Up to 70 days the outer layer was cubic Fe₃O₄ but after 90 days it was α-Fe₂O₃, probably with some γ-Fe₂O₃ and otherminor impurtties such as hydroxides. The influence of impurities on the oxide is emphasised by a weight loss of 5–7 % which occurred upon heating the specimens to 300° in vacuo after 120 days. γ-Fe₂O₃ and other minor impurities such as hydroxides. The influence of impurities on the oxide is emphasised by a weight loss of 5–7% which occurred upon heating the specimens to 300° in vacuo after 120 days.     

Thermodynamics of Iron Oxidation in Metallurgical Slags

The state of oxidation of a pyrometallurgical process, given by the partial pressure of oxygen and the temperature, is one of the important properties monitored and controlled in the smelting and refining of iron and the nonferrous metals. This article reviews the thermodynamic background for this quantity and examines some empirical methods for its estimation and use. The emphasis is on copper smelting, but the same principles apply to iron, nickel, lead, and zinc processes.     

To the Low-Temperature Passivity of Iron at the Gaseous Oxidation

The low-temperature passivation of the oxide growth on iron is studied with the use of digital ellipsometry at a temperature of 300°C and an oxygen pressure from 10^–3 to 1 mmHg. The maximum increment in the oxide thickness as a function of the oxygen pressure P _a–p is observed in an hour of exposure, which indicates the active–passive transition. This passivity of iron and other metals can be caused by the multilayer and multiphase structure of the oxide film formed. As the oxygen pressure is increased, an external protective hematite layer appears on iron, and the inner quickly growing magnetite layer has no time to reach its limiting thickness. Shortening of the period of a rapid growth of magnetite, which is observed upon the increase in the oxygen pressure at the same exposure, results in the maximum of the summary thickness of the layer at a certain pressure P _a–p. Hematite over the magnetite layer is usually formed as laterally spreading islets, the coalescence of which sharply decelerates the oxidation. In the time–pressure–oxide thickness plot, the areas of the low-temperature passivation of iron can be distinguished in wide ranges of temperature and pressure. The electrophysical treatment in the range of the active–passive transition sharply intensifies the oxidation of iron-based alloys and leads to the formation of layers with a substantial thickness and protective ability.     

一种防止冲天炉铁液氧化的措施

在冲天炉铁料材质稳定、铁焦比比较合理的情况下 ,适当调整送风强度 ,是排除铁液氧化的有效措施。     

Effect of Oxygen Content on the Oxidation of Pure Iron

The oxidation of pure iron with various oxygen contents was studied. Pure iron and ferrite containing different amounts of oxygen were oxidized for 1–5 hr in two types of oxidation atmospheres at 850°C. Pure iron (0.0037% oxygen) oxidized more rapidly than ferrite (0.017% oxygen). Oxidation is higher in the moist ambient atmosphere than in dry air. The oxidation rate was not proportional to the amount of oxygen in the samples.     

Oxidation Potentials in Iron and Steel Making

The state of oxidation of a pyrometallurgical process given by the partial pressure of oxygen and the temperature (the oxidation potential) is one of the important properties monitored and controlled in the smelting and refining of iron and the nonferrous metals. Solid electrolyte sensors based on ZrO₂ and a reference electrode such as Cr/Cr₂O₃ to measure the oxygen pressure found early application in the steel industry, followed soon after in copper, nickel, lead, and zinc smelting. Similar devices are installed in automobile postcombustion/exhaust trains as part of emission control systems. The current discussion reviews this technology as applied in the primary steps of iron and steel making and refining.     

耐海水腐蚀铸铁的抗氧化性

探讨HD型铸铁（一种耐海水腐蚀低合金铸铁）高温氧化时能否形成类似保护膜的研究结果表明,HD铸铁在高温下形成的氧化膜与一般铸铁无本质区别,其抗氧化性主要与铸铁中Cr、Al、Si含量有关。     

烧结机篦条材料的摩擦磨损及高温抗氧化性能

以烧结机篦条用高铬铸铁为研究对象,结合工矿条件考察其摩擦磨损及高温抗氧化性能。结果表明:在室温干滑动磨损条件下,转速和载荷的增加会加剧高铬铸铁的摩擦磨损;在高温条件下,高铬铸铁的抗氧化能力主要随保温时间的增长逐渐减弱,但是基本不受烧结工况下剧烈温度变化的影响。     

Initial Oxidation of Pure Iron and the Effect of the Allotropic Transformation

Abstract

A volumetric method has been used to study the kinetics of the initial oxidation of oure iron at two pressures of dry oxygen (viz. _p O₂ = 7·6 and 29 cm mercury) in the range 800–1000° in which the first allotropic transformation point of iron occurs. It was found that the oxidation of both body-centred cubic (b.c.c.) and face-centred cubic (f.c.c.)–iron at _p O₂ = 7·6 cm and of only b.c.c. at _p O₂ = 29 cm follows a modified parabolic law; a true parabolic law was found to operate in the oxidation of f.c.c.–iron only at _p O₂ = 29 cm. An anomaly, which is obtained in the Arrhenius plot at the allotropic change point of iron (～911°), is attributed to the effect of phase-boundary reactions on the oxidation kinetics. It would appear from the concept of vacancy distribution in iron, that for a modified parabolic law, it is the metal/oxide interfacial reaction in f.c.c.–iron and the oxide/oxygeninterfacial reaction in b.c.c.–iron that governs the phase-boundary controlled reaction rate.     

喂线法在铁液球化-孕育处理中的应用

介绍了在内蒙一机集团第十分公司用喂线法对铁液进行球化-孕育处理的结果.与冲入法对比证明:用喂线法进行铁液球化-孕育处理可使球化等级和石墨球径提高至少一个等级,脱硫率提高10个百分点,主要球化元素的成分偏差稳定控制在0.004%以内,这样可以得到质量高且稳定的球铁铸件,增加铸件附加值.同时,采用喂线法后可以增大使用回炉料的空间,降低操作人员劳动强度,为企业带来明显的直接和间接经济效益.     

用喂线法进行球化脱硫处理的工业化试验

在工业上用喂线法对铁液进行球化脱硫处理，通过试验确定最佳喂线速度和合适的铁液处理温度，并对喂线法与冲入法进行了技术、经济的比较。结果表明，最佳喂线速度是15m/min；铁液处理温度一般在1400－1450℃之间；喂线法处理比冲入法处理稳定，且每吨铁液用喂线法比用冲入法处理节约成本14元。     

蠕墨铸铁喂线蠕化处理工艺的研究

研究喂线蠕化处理工艺生产蠕墨铸铁的可行性,通过试验分析了蠕化芯线的化学成分及加入量对蠕化率的影响,确定了喂线蠕化的工艺参数.试验还通过对喂线法和冲入法的比较,体现出喂线工艺在生产中的优势.结果表明,喂线蠕化处理工艺可行,蠕化情况良好,蠕化率稳定.     

微米级铁基纤维的抗氧化性和磁性

微米级铁基纤维由Cu-11Fe-4Cr原位复合线材萃取得到。研究了在大气环境中加热对纤维样品结构和磁性的影响。采用X射线衍射和扫描电镜观察分析了样品的结构和形貌,采用振动样品磁强计测试了样品的磁性,利用热重-差热试验分析了纤维的热稳定性。结果表明,原始态纤维为铁素体结构,饱和磁化强度约为120A.m2.kg-1;在空气中600℃以下加热,纤维保持铁素体结构不变,经800℃以上加热后,由铁磁性的α-(Fe,Cr)固溶体转变为顺磁性的(Fe0.6Cr0.4)2O3,样品的饱和磁化强度显著下降。     

注塑机和压铸机用球墨铸铁模板切削加工性能影响因素研究

研究了球墨铸铁模板的化学成分、基体组织、硬度、铸造工艺、热处理等对其切削加工性能的影响。模板化学成分不合理、形成碳化物元素含量过高、模板中含有高熔点的夹杂物、局部的白口和反白口、未熔尽残留物、硬度不均匀等材料原因,以及铸造工艺方面的冷却速度、开箱温度、铸件尺寸精度超差和不稳定、刀具和切削用量不合适等非材料因素均可能引起切削问题。提出了从熔炼入手,控制炉料质量、控制形成硬质点的合金元素加入量、消除夹杂物、提高基体组织的均匀性、严格控制铸造工艺过程等解决措施,以获得良好的切削加工性能。     

The Inhibitive Effect of Traces of SO2 on the Oxidation of Iron

The oxidation of Fe was investigated at 500–700°C in the presence of O₂ with 0–1000 ppm SO₂. The exposures were carried out in a thermobalance and lasted for 24 h. The oxidized samples were investigated by grazing-angle XRD, SEM/EDX, GDOES and XPS. The rate of oxidation of pure iron is slowed down by traces of O₂ in O₂ below 600°C while SO₂ has no effect on oxidation rate at higher temperatures. Exposure to SO₂<600°C resulted in the formation of small amounts of sulfate at the gas/oxide interface. In addition, sulfur, probably sulfide, accumulated at the metal/oxide interface. The influence of SO₂ on oxidation rate is attributed to surface sulfate. The sulfur distribution in the scale is rationalized in terms of the thermodynamic stability of compounds in the Fe–O–S system. Exposure to SO₂ caused the formation of hematite whiskers.     

微米级铁基纤维的抗氧化性和磁性

微米级铁基纤维由Cu-11 Fe-4Cr原位复合线材萃取得到.研究了在大气环境中加热对纤维样品结构和磁性的影响.采用X射线衍射和扫描电镜观察分析了样品的结构和形貌,采用振动样品磁强计测试了样品的磁性,利用热重-差热试验分析了纤维的热稳定性.结果表明,原始态纤维为铁素体结构,饱和磁化强度约为120 A·m2·kg-1;在空气中600℃以下加热,纤维保持铁素体结构不变,经800℃以上加热后,由铁磁性的α-(Fe,Cr)固溶体转变为顺磁性的(Fe0.6 Cr0.4)2O3,样品的饱和磁化强度显著下降.     

用喂丝法工艺处理铁液

采用喂丝法球化处理，已在离心球墨铸铁管的大批量生产中得到应用，年处理球铁量达70多万吨。喂丝蠕化处理方法与喂丝球化处理方法相同。由于喂丝法有控制精确、改善劳动环境等优点，尤其可用计算机根据快速测定的硫量精确地控制喂丝量，因而能有效地控制蠕化质量。