球化退火温度对65Mn—N组织与性能的影响

为确定合适的65Mn—N钢球化退火温度,模拟工厂的等温退火工艺对65Mn—N钢进行退火处理,并对钢的组织与性能随退火温度的变化规律进行了研究。结果表明,将热轧态的试样在720℃保温9h,然后炉冷至550℃．最后空冷时,铜的组织为铁素体和分布较为均匀的球粒状Fe3C碳化物,钢的显微硬度较低。     

High strength low carbon hot rolled δ-ferritic steel: microstructure and mechanical properties

Abstract

The present study concerns the development of high strength low carbon hot rolled bainitic and martensitic δ transformation induced plasticity steels. Equilibrium and para-equilibrium phase evolution have been examined by carrying out thermodynamic calculation using MT-DATA software. Microanalysis demonstrates that both manganese and aluminium partition between liquid and solid phases. Isothermal treatment and tempering at 350°C for bainitic and martensitic microstructures respectively have yielded the best combination of strength and ductility. All the steels have exhibited the continuous yielding behaviour and favourable ratio of yield and tensile strength, which are desirable for formability. The annealed steel has yielded a high level of tensile strength with the static toughness value in between the conventional transformation induced plasticity assisted and dual phase steels.     

Enhancement of pearlite transformation by Warm Rolling in 1.0C-1.5Cr Steel

Isothermal and non-isothermal pearlite transformations under 840°C warm-rolled and 950°C hot-rolled were researched. It was found that the pearlite nuclei at grain boundary and defects were increased by warm deformation. The results showed that the incubation time was shortened in the isothermal pearlite transformation and the volume fraction of pearlite was increased in continuous cooling condition by warm deformation. The pearlite transformation behaviour under continuous cooling condition was predicted by the formula of Umemoto. The critical cooling rates of the fully pearlite structures formed under warm deformation condition and hot deformation condition were calculated.     

珍珠岩轻质墙材的研制开发

本文介绍了珍珠岩的性能、用途 ,膨胀珍珠岩的加工方法与影响珍珠岩膨胀倍数的主要因素 ,以及两种轻质墙材的配方、生产工艺和性能指标。     

15CrMo钢珠光体球化对机械性能的影响

石油化工设备所用的铁素体－珠光体型耐热钢在长期高温条件下服役后，显微组织中的片状珠光体将转变成球化体。为搞清这种组织变化对机械性能造成的影响，选用石化设备常用的１５ＣｒＭｏ钢，对其进行了不同热处理工艺条件下的模拟球化退火处理，获得了不同的组织形态。对３种具有不同组织形态的试样进行了高温拉伸试验。结果表明，珠光体球化使钢的高温强度降低，尤其是高温屈服强度降低显著。球化程度愈严重，钢的高温强度愈低。该结果可为球化后的设备能否继续服役提供一定的参考依据。     

ON THE PERMEATION OF SOME GASES THROUGH THE LAMELLAE OF STATIC FOAMS. A PRELIMINARY APPROACH

Basing on the capillary method for the determination of foam bubble size, a method was proposed for establishing values of permeability coefficients of several gases. The permeability coefficients of He, Ar, H₂, N₂, CH₄ through the lamellae of static foam bubbles were preliminarily determined using this method.

A rough dependence of the N₂ permeability coefficient through the lamellae of static foam bubbles on the foam wetness and surfactant concentration was also found.

The results obtained lead to the conclusion that the Princen-Mason diffusion model of gas permeation through an isolated soap film was inadequate in the case of permeation through lamellae of bubbles forming a static foam.

A hypothesis that the gas permeation through the lamellae of a static foam is primarily caused by liquid convection in the lamellae core was put forward.     

珍珠岩尾砂釉的研制

本文研究了珍珠岩尾砂在釉面砖釉料中的应用。试验结果表明：由于珍珠岩尾砂是一种酸性玻璃质熔岩,且烧失量小,膨胀系数小,在低温快速烧成釉料中引入,能够降低釉的烧成温度,并能缩短烧成周期,减少针孔及釉裂倾向。     

Effect of Cu,Mn and Sn on pearlite growth kinetics in as-cast ductile irons

In a previously published work, pearlite growth in cast irons was investigated and it was claimed that growth kinetics of pearlite in nodular cast iron does not depend on alloying elements and that only the start temperature for the transformation is modified. Since then, the authors have investigated the effect of copper at low level of manganese and the combined effect of copper and tin at intermediate manganese contents. In the first case, thermal records confirmed that copper decreases the formation temperature for both ferrite and pearlite. In the second work, an optimised content for tin, manganese and copper was found so as to improve mechanical properties while keeping fully pearlitic structures. The thermal records obtained during this latter study are here used to estimate the pearlite growth kinetics and the effect of copper and tin on it. Tin has been shown to reduce pearlite undercooling (increase of start transformation temperature) and thus to favour the formation of this constituent.     

共析分解

对以钢中珠光体相变为典型示例的共析分解研究工作给以浅简总结。在珠光体相变中,进行铁素体和渗碳体的合作形核和长大。珠光体相变时的领先形核相,铁素体或渗碳体,及其形核位置,晶界或晶粒内部,都决定于合金的成分、晶界偏聚、夹杂物、组元的扩散系数及形核能垒。由体扩散和界面扩散两类长大机制所导得的过冷度ΔT和珠光体片层间距S之间,由Zener所示的关系式:ΔT×S=const.都与不少试验结果相符。由于珠光体/奥氏体间界面含有不动位错及其他缺陷,理论上台阶机制应为合理的珠光体长大机制。先进实验已观察到长大台阶以及铁素体/奥氏体、铁素体/渗碳体和渗碳体/奥氏体之间都具有各自的位向关系。层状珠光体的形态,即珠光体片间距受控于过冷度,并决定珠光体的强度。     

不同形态矿物复合增强LDPE的研究

利用硅灰石、白云母和珍珠岩等3种具有特殊晶体结构和形态的矿物粉体,进行表面改性处理,与低密度聚乙烯(LDPE)复合加工制备复合材料。结果表明,甲基丙烯酰氧基三甲氧基硅烷对3种矿物粉体的改性效果较好;在总用量为30%,硅灰石∶白云母∶珍珠岩为1∶1∶1时,复合材料的强度、耐磨性、流动性都得到增强,复合材料性能优于纯LDPE。