Q345C低合金高强度结构钢板的试制

介绍采用氧气顶吹转炉→吹氩喂丝→板坯连铸→控制轧制生产Q345C低合金高强度结构钢板的生产工艺。通过对化学成分的合理设计及制订适合该厂冶炼、连铸、轧制的工艺，采取微合金化和控轧控冷相结合的有效技术措施，提高钢板的综合性能，特别是低温冲击韧性。生产的Q345C钢板，其产品质量完全符合GB／T1591—94标准要求。     

Formation mechanism of Ti5Si3 powder by mechanical alloying

The formation mechanism of stoichiometry Ti5Si3 by mechanical alloying (MA) from elemental powders has been investigated. The results of XRD and SEM analyses of the powder show that Ti5Si3 can be synthesized by MA in a planetary mill with two different formation mechanisms. Ti5Si3 was formed gradually with the mechanical collusion reaction (MCR) mechanism under a lower impact energy, and the Ti5Si3 was formed abruptly with the self-propagating high-temperature synthesis (SHS) formation mecha-nism under a higher impact energy.     

Fuzzy Modeling of Prediction M_s Temperature for Martensitic Stainless Steel

1　IntroductionWhenexaminingphasetransformationsinsteel,martensitestarttemperatureMsisanimportantparame ter.Sincetheaustenitetransformsintomartensiteisnon diffusionaltransformation ,thecharacteristictransforma tiontemperaturedoesnotdependonthepriorthermal…     

利用EET理论预测Fe-C-Cr系高铬铸铁的淬硬性

为了揭示高铬铸铁组织的微观本质并利用其分析结果预测合金的淬硬性，利用余瑞璜的固体与分子经验电子理论(EET)和Fe-C-Cr三元系平衡相图对Fe-C-Cr三元系高铬铸铁合金奥氏体的价电子结构进行了分析。结果表明，在工业应用的成分范围内C-Cr键是合金奥氏体所有键中的最强键，形成C-Cr偏聚单元。wcr/wc≥6时，含C-Cr结构单元的权重会大大提高，促进了奥氏体的陈留，可以获得奥氏体基体组织。当wcr/wc=5．5-6．5时，Fe-C-Cr三元系高铬铸铁可获得最佳的淬硬性。     

Surface Alloying of Nitrogen to Improve Corrosion Resistance of Steels and Stainless Steels

It is well known that the addition of nitrogen to steels and stainless steels enhances the passivity and localized corrosion resistance, in addition to improving the mechanical properties. Selective alloying of surfaces of steels and stainless steels with nitrogen could also enhance the corrosion resistance and improve the mechanical properties without affecting the bulk properties. Techniques like ion implantation, laser alloying, nitriding, etc. can be effectively used to introduce very high levels of nitrogen. In addition, these techniques can also produce modified surfaces with novel microstructures to further improve the properties. The surface alloying methods also provide an opportunity to selectively nitrogenate the surface of finished components in order to obtain better properties. The review highlights the techniques, modifications and the properties obtained further.     

低温退火时间对Laves相Cr2Nb固相热反应合成的影响

研究了900℃退火时，退火时间对Cr—Nb机械合金化（MA）粉的Laves相Cr2Nb固相热反应合成的影响规律，获悉了15hMA粉在900℃低温退火时能使Cr2Nb固相热反应合成充分进行的最短时间。优化出的Cr2Nb固相热反应合成低温退火时间，为通过MA＋热压（或烧结）工艺路线制备出具有微／纳米晶结构的高强高韧Cr2Nb合金或Cr2Nb基复合材料提供了可能性。     

机械合金化Cu－5Cr合金的组织性能研究

研究了机械合金化制粉、热静液挤压致密制备的Ｃｕ－５Ｃｒ合金的组织与性能。机械合金化Ｃｕ－５Ｃｒ合金由于细晶强化和弥散强化的作用，具有很高的强度（σｂ≥７５０ＭＰａ），经热处理后，合金具有较高的延伸率（δ≥８％）和导电性（≥６０％ＩＡＣＳ）。材料晶粒达到０．１μｍ级，析出的Ｃｒ粒子达到纳米级。     

机械合金化制备金属难熔化合物

在介绍机械合金化特点的同时，重点研究和讨论了机械合金化制备金属难熔化合物的过程及机理，并认为机械合金化是制备难熔化合物及其材料的一种行之有效的方法。