DT-CA-09型增碳剂的选用及实验分析

使用中频电炉熔炼合成铸铁,必须采用增碳技术,以保证铁液中碳含量在工艺要求的范围内.在中频电炉熔炼新工艺中,根据增碳剂分类及增碳原理,结合电炉熔炼对增碳剂的要求,选用了国产DT-CA-09型增碳剂.实验证明,所选用增碳剂可满足目前中频电炉熔炼工艺需求.     

增碳剂在冲天炉熔炼条件下的应用

通过分析研究增碳剂的增碳机理,结合冲天炉熔炼过程中特有的熔化规律及成分波动特点,制作了一种冲天炉炉内增碳专用的增碳剂,降低了熔炼过程中生铁的加入量,提高了冲天炉熔炼铁液的质量.试验结果表明:专用增碳剂的增碳效果较好,能够适应冲天炉熔炼的复杂环境.增碳后的铸件金相组织改善,力学性能较高,完全能够满足生产工艺要求.     

中频感应电炉熔炼铸铁增碳剂吸收率的影响因素

中频感应电炉熔炼铸铁的过程与冲天炉熔炼的区别在于增碳工艺和合金加入方式的不同.分析了增碳剂化学成分和粒度、金属炉料物理状态和化学成分对增碳剂吸收率的影响.通过合理控制中频感应电炉熔炼铸铁过程中的增碳剂加入方式、熔化过程时长、铁水过热温度、合金化元素及增碳剂加入量,使增碳剂被充分吸收,并减少其烧损,在保证铁水质量的同时,提高设备的熔化效率,降低生产成本.     

合成铸铁的生产及应用

熔炼合成铸铁,由于废钢加入量大,增碳技术成为其生产的关键技术。对合成铸铁的增碳原理、铸铁熔炼工艺进行了分析。结果表明,采用晶体石墨增碳剂,电炉熔炼合成铸铁的增碳速度明显高于非石墨增碳剂;且晶体石墨增碳剂可作为石墨的外来晶核,促进细片状A型石墨的形成,铁液白口倾向小,力学性能提高。     

用低温增碳工艺在感应炉内熔炼可锻铸铁

介绍的是采用低温增碳工艺在感应电炉内熔炼可锻铸铁的实践经验.结果表明,采用这种办法能使铁水大量增碳,因而可以显著减少生铁用量而相对较多地配入废钢、增碳剂.     

合成铸铁增碳案例浅析

介绍了熔炼合成铸铁的增碳工艺原理,阐述了增碳剂加入方式、铁液化学成分及增碳剂品质对增碳剂吸收率的影响。在分析实际增碳案例基础上,指出选用合适的增碳剂,并大量使用废钢生产的合成铸铁,与传统熔炼工艺相比在成本和质量上都具有优势。     

增碳剂对球墨铸铁的孕育作用

针对铁素体球墨铸铁的局部缩松缺陷,采用提高含碳量的措施并认识到增碳剂对球墨铸铁的孕育作用。通过研究分析并对其相关问题进行讨论,得出了在球墨铸铁熔炼过程中使用增碳剂增碳会产生良好孕育作用与效果的结论,并对球墨铸铁的凝固结晶分析作了另类的诠释。突破性地提出利用增碳剂对球墨铸铁进行强化孕育,促进石墨形核与长大,这对提高球墨铸铁生产工艺技术的发展与进步是非常有意义的。     

高比例废钢增碳在12.5t中频炉上的应用

介绍了高比例废钢增碳熔炼工艺在12.5 t中频炉上的应用，通过在不同的熔炼温度下取样分析，在不同的配料比例和不同的加料顺序下跟踪增碳剂的吸收率，对废钢增碳最佳的熔炼工艺参数进行分析、研究，结果表明：增碳剂分批加入到炉膛中，并且加入到废钢层之间，熔炼温度在1500～1550℃范围内时，增碳剂的吸收率较高，达到85%。     

合成球墨铸铁技术在轧辊生产中的应用

对复合轧辊所用合成球墨铸铁的增碳原理及实际生产工艺进行了论述,并分析了采用增碳工艺后合成球墨铸铁的组织和性能,结果表明,影响增碳吸收率的因素主要有增碳剂的粒度、熔炼过程中铁液的搅拌、铁液的化学成分、铁液饱和浓度、增碳剂加入量.采用增碳工艺后,铸铁组织明显改善,石墨均匀分布,且形态得到明显改善,石墨球化良好,未出现片状组织,铸件硬度提高,硬度更加均匀.     

新型增碳剂在铸铁轧辊上的应用

用工频电炉熔炼铸铁轧辊时，采用新型增碳剂可以有效地解决铁液的增碳问题。新型增碳剂含碳量高，密度大，它和钢铁料同时装入或者加在铁液表面上，平均增碳效率分别为92％和88％，增碳效果稳定。     

胫骨生物陶瓷复合材料的微结构增韧机理

扫描电镜观察显示胫骨是一种由羟基磷灰石和胶原蛋白组成的自然生物陶瓷复合材料.羟基磷灰石具有层状的微结构并且平行于骨的表面排列.观察也显示这些羟基磷灰石层又是由许多羟基磷灰石片所组成,这些羟基磷灰石片具有长而薄的形状,也以平行的方式整齐排列.基于在胫骨中观察到的羟基磷灰石片的微结构特征,通过微结构模型分析及实验,研究了羟基磷灰石片平行排列微结构的最大拔出能.结果表明,羟基磷灰石片长而薄的形状以及平行排列方式增加了其最大拔出能,进而提高了骨的断裂韧性.     

Prospects of the Use of Synergetic Approach to Solution of Problems of the Science of Nanomaterials

A synergetic approach to solution of problems of self-controlled synthesis of nanostructures and creation of self-organizing nanotechnologies is considered in connection with the superproblem of creation of materials with functional properties resembling those of biosystems. __________ Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 7, pp. 55 – 61, July, 2005.     

Kinetics of the oxidation of metals — Influence of self-diffusion of metal

The importance of the self-diffusion of a metal during its oxidation by a gas is treated for the cases of nonstoichiometric oxides having either interstitial cation or cation vacancies. We have established a general relationship for the reaction rate when a mixed diffusion process occurs. From this relationship, we have shown that the pressure dependence can be different, according to whether the rate-determining process is the self-diffusion through the metal or through the product.     

Features of formation of the structure in production of blanks of disks of heat-resistant nickel alloys

Conclusions To provide a high level of mechanical properties in wrought blanks of cast ÉP741NP and ÉP962 alloys it is necessary to form controlled structures. A necklace-type structure formed in homogenizing isostatic treatment, subsequent thermomechanical working including alternation of the operations of deformation in the (+)-area and recrystallization anneals, and final heat treatment is preferable. The temperature conditions of all stages of thermomechanical working are strictly controlled, especially the final operation of deformation and heating for hardening. To eliminate hardening cracks and distortions it is necessary to use molten salts at t=600°C as quenchants. The use of multiple production operations makes it possible to significantly reduce the structural inhomogeneity related to inhertance of the original dendritic structure. However, the structure of the final semifinished product is nevertheless characterized by a difference in occurrence of the processes of polygonization and recrystallization between the former dendritic cells and the interdendritic spaces in deformation and heat treatment.To obtain structurally homogeneous blanks for gas turbine engine parts it is necessary to use basically new methods of remelting such as vacuum double electrode remelting and electron beam remelting with an intermediate vessel.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 12, pp. 25–29, December, 1991.     

Ab-initio calculation of enthalpies of formation of intermetallic compounds and enthalpies of mixing of solid solutions

A large number of ab-initio calculations of energies of formation of intermetallic compounds have been performed in the last 15 years. The currently used methods are listed. The paper presents a review of the aluminium based compounds which have been studied. Comparisons of calculated and experimental enthalpies of formation are provided for aluminim-3d and-4d transition metal alloys at equiatomic composition. The modelling of the enthalpies of mixing of solid solutions based on a given lattice is described.     

试论洋务派教师聘任的思想

洋务派在洋务学堂的办学活动中,为了解决西学专业学科的教学困难,采用了聘请外籍教师的应急措施.他们以真才实学,合同制管理作为主导思想,并认为这种解决师资的途径只是权宜之计,并非久远.从客观上看,洋务派的教师聘任思想有深刻的历史影响.