DEVELOPMENT OF PM VALVE SEAT INSERTS USED IN JL462Q ENGINE

A process to develop the valve seat inserts in JL462Q engine is studied. The material is an iron-based alloy without Cr. The results show that the microstructures and properties of the product are as good as those of the product made in Japan. The effects of Mo. Ni. Co. Cu etc. in the alloy are also discussed respectively.     

X80管线钢性能特征及技术挑战

针对X80管线钢研发与应用现状以及目前存在的问题,综述了影响X80管线钢性能的主要因素、研究进展以及发展X80钢管道面临的技术挑战。详细分析了X80管线钢的冶金特征与组织结构,概述了X80管线钢的焊接工艺、焊接冶金学特征及性能,总结了X80管线钢的机械性能和力学特征。具体讨论了X80管线钢在服役环境中的失效机制,包括腐蚀、氢致开裂、焊缝区失效、应变失效等,并以此为基础,探讨了发展X80钢管道需要克服的技术挑战,以保障油气安全、高效输送以及能源管道的可持续发展。(图1,表8,参86)     

Analysis of diffusion equation with the second and third boundary conditions based on steady state approximation

One dimensional diffusion equation is widely used to describe mass transfer in particles or droplets in a reactor. The length of the definition domain of the one-dimension Fick equation is limited, because it is determined by the scale of the particles or the droplets. The diffusion equation with a certain length of definition domain has no analytic solution unless series solution. So, to obtain approximate solutions of diffusion equation is of theoretical significance and practical significance. Firstly, assumption of constant concentration variance ratio is used instead of assumption of constant concentration frequently used in kinetics of process metallurgy. Secondly, a detail process to deal with diffusion equation based on steady state approximation is given, and the approximate solutions of the diffusion equation at certain conditions are obtained at the same time. By comparing the approximate solutions with the numerical solutions, it is concluded that the diffusive process of non-steady state is considerably well predicted by the approximate solutions, and approximate solutions accord with the situations being close to the final steady state a little better than accord with the situations being close to the begin of the diffusion, and it fairly satisfies the total mass balance.     

冶金工程试验中含有定性因素的回归设计

在许多实际问题中,会遇到含有定性因素的试验,如何用回归正交设计去分析讨论它.本文通过冶金工程试验中含有定性因素的1个实例,简要而又系统地讨论它.     

液体金属和合金的盐雾化

介绍了作者发明的一种新型的流体金属和合金的雾化制粉方法，即采用含有固体盐（NaCl）颗粒的高速气流对液体金属或合金进行雾化得到粉末的方法（简称为固体雾化法）。通过对几种金属和合金粉末制备工艺的研究得到如下结论；在同等气体压力和流量条件下，采用含有固体盐颗粒的高速气流雾化金属熔体制得的粉末比不含固体盐颗粒的高速气流雾化制得的粉末的粒度细得多，而且粉末粒度分布较窄，粉末冷却速度较大，采用固体盐雾化法制务金属粉末时，盐的流率愈大、流速愈快、粒度愈细，则雾化制得的粉末粒愈细。     

表面改性粉末冶金件耐磨性影响因素分析

用纳米Al2O3与铁粉相混合作为铁基粉末冶金件的表面改性材料，通过激光熔覆试验对冶金件进行表面改性。运用优化设计法。在MM-200摩擦磨损试验机进行摩擦磨损试验，纳米Al2O3与铁粉涂层激光熔覆后，粉末冶金件表面耐磨性显著提高，得出影响耐磨性因素的回归方程。方程表明：纳米Al2O3的质量分数与载荷都是影响耐磨性的显著因素，且载荷的影响较纳米Al2O3质量分数显著。磨损量对比曲线显示，当纳米Al2O3质量分数为4％、8％时，随载荷增大磨损量趋于一致。     

Producing More-color Bricks with Discard Slag of Nanking Steel

In order to change the abut 700 thousand ton discard slag of Nanjing steel group limited company (for short name: Nanking steel ) into utilization material , and utilize them efficiently, fully, without pollution, a series of experiments were carried out on producing more color brick. The BF slag and LD slag and sticky matter were first mixed together, then sprinkled noting, concreted, took off the mold and protected. The process and technology of producing the more color brick was studied. The result shows that the various functions of the more color brick meet the building materials standard.     

中国矿业用地现状分析

当前中国矿业用地存在土地使用权取得方式单一、使用粗放,开采占地方式多、占用数量大,各类占用破坏严重,重开发生产、不注重保护治理,矿山开采企业经营困难、难以落实复垦政策等五大特征.文中提出了解决矿山用地问题的途径,提出拓宽供地方式、建立专门复垦管理机构、专门基金、多方承担复垦工程任务和加强执法力度等.     

中国矿业用地现状分析

当前中国矿业用地存在土地使用权取得方式单一、使用粗放，开采占地方式多、占用数量大，各类占用破坏严重，重开发生产、不注重保护治理，矿山开采企业经营困难、难以落实复垦政策等五大特征。文中提出了解决矿山用地问题的途径，提出拓宽供地方式、建立专门复垦管理机构、专门基金、多方承担复垦工程任务和加强执法力度等。     

含铬石墨／铜基复合材料的制备及性能

采用化学反应方法使平均粒径２－３μｍ的铬质点在天然鳞片石墨表面原位生成,由粉末冶金制备的含有这种铬质点的石墨／铜基复合材料的电阻率为９．５μΩ．ｃｍ,且磨损率极低。