盐浴温度对含钨CADI材料组织和性能的影响

将含钨的碳化物的等温淬火球墨铸铁(Carbidic Austempered Ductile Iron简称CADI)铸件在900℃高温奥氏体化后,在盐浴不同温度等温处理及保温不同的时间,对试样作力学性能和耐磨性对比测试。结果表明,当盐浴温度为280℃时硬度最高,耐磨性最好。但冲击韧度较小;当温度提高到340℃,C曲线左移,贝氏体晶粒粗化,试样的硬度下降此时材料的冲击韧度最好。     

等温淬火温度对CADI组织及性能的影响

针对含一定碳化物等温淬火球墨铸铁(CADI),研究了等温淬火温度对贝氏体相形貌、残余奥氏体量、力学性能及耐磨性能的影响,分析了冲击断裂机理。结果表明,对于铸态组织为75%珠光体+铁素体+10%碳化物试样,经920℃×1.5 h奥氏体化后,在240℃、280℃及320℃进行等温淬火处理2 h,随着等淬温度的提高,贝氏体的形貌由针状变粗至羽毛状,残余奥氏体量增加,硬度减低,冲击韧度提高,相对耐磨性降低。最佳等温淬火温度为280℃,此热处理工艺后组织为贝氏体+22.33%残余奥氏体+10%碳化物,硬度HRC 50.9,冲击韧度32.72 J/cm2,断口呈混合断裂特征,相对耐磨性比320℃时增加11%。     

亚温奥氏体化等温淬火球墨铸铁的研究

研究了亚温奥氏体化等温淬火工艺对等温淬火球墨铸铁组织和力学性能的影响.在等温淬火工艺(等温淬火温度370℃,等温淬火时间120 min)一致前提下,当奥氏体化温度在820～880℃区间变化时,随着奥氏体化温度的升高,热处理后组织中针状铁素体的数量愈来愈少;当奥氏体化温度为880℃时,组织已经全部奥氏体化.此外,随着亚温...     

热处理工艺对含硼球墨铸铁组织和力学性能的影响

采用磨损试验机、金相显微镜,研究热处理工艺对含硼球墨铸铁(CADI)组织和力学性能的影响。结果表明,经960℃高温预处理7 min、900℃奥氏体化保温90 min及等温淬火保温90 min后,铸铁组织由球状石墨、针状铁素体、高碳残余奥氏体和一定量的碳化物组成。随着等温淬火温度由250℃升至310℃,铁素体组织粗化,残余奥氏体含量逐渐增加,硬度降低,冲击性能提高,耐磨性能降低。     

热处理工艺对双相等温淬火球墨铸铁组织的影响

利用扫描电镜分析了热处理工艺对双相ADI(等温淬火球墨铸铁)组织的影响.结果表明:当奥氏体化温度在820～880℃时,随着奥氏体化温度的升高,铁素体的含量逐渐减少,奥氏体的含量逐渐增加,当奥氏体化温度达到880℃时,基本全部奥氏体化.当等温淬火温度为250～370℃时,随着等温淬火温度的升高,组织由细针状铁素体、残余奥氏体及破碎状铁素体转变成大量的羽毛状贝氏体型铁素体、破碎状铁素体和较多的残余奥氏体.当等温淬火时间为30～90 min时,等温淬火时间较短时,组织为少量马氏体、破碎状铁素体、针状铁素体和残余奥氏体,当等温淬火时间超过90 min时,奥氏体容易发生分解,生成铁素体和碳化物.     

奥氏体等温淬火灰口铸铁

选用三种牌号灰铸铁 （ Ｈ Ｔ１５０ 、 Ｈ Ｔ２００ 、 Ｈ Ｔ２５０） , 采用不同热处理 （９００ ℃奥氏体化后, 在２８０ ℃、３２０ ℃、３７０ ℃下进行等温淬火） 后, 分析了热处理后的力学性能等与等温温度的关系; 通过对亚共晶、过共晶灰铸铁等淬后性能的对比, 发现过共晶灰铸铁热处理后性能提高幅度虽不如亚共晶灰铁, 但仍有一定改善; 应用表明, 奥氏体等温淬火工艺应用于灰铸铁件, 获得的奥贝灰铁件兼具较好的抗拉强度和耐磨性。     

等温淬火高硅铸钢的组织转变

采用扫描电子显微镜对高硅铸钢等温淬火后的显微组织进行了系统研究。结果表明,高硅铸钢经等温淬火热处理后,可以得到单一的由贝氏体铁素体和富碳的残余奥氏体交替排列的奥-贝双相组织（Aus-ferrite）,组织中没有碳化物析出。在400℃等温时,等温时间过长会导致残余奥氏体分解为铁素体和碳化物。经280℃等温淬火热处理,显微组织随等温时间的变化不大,或者几乎没有变化。     

等温淬火工艺对高碳钢组织与性能的影响

通过调整奥氏体化温度和保温时间、等温温度和等温时间等工艺参数,研究了等温淬火工艺对高碳钢组织与性能的影响。结果表明,高碳钢适宜的等温淬火工艺为900℃×30 min奥氏体化+盐浴300℃×40 min。     

等温处理工艺对等温淬火球铁显微组织和硬度的影响

上世纪70年代,通过奥氏体等温淬火开发出抗拉强度大于1000MPa、伸长率大于15％的高强度、高韧性等温淬火球铁。利用正交试验法,研究了等温淬火工艺参数对等温淬火球铁显微组织及硬度的影响。结果发现,在设计的试验工艺内全部可以得到以针状铁素体和富碳奥氏体为基体的等温淬火球铁组织;在等温淬火工艺中,等温淬火温度对试样硬度影响最为显著,其次是奥氏体化温度与奥氏体化时间,而等温淬火时间对于试样硬度的影响最小。     

等温淬火对连铸球铁型材组织和硬度的影响

为了探寻水平连铸球墨铸铁QT500-7型材的最佳等温淬火工艺,运用正交试验方法对奥氏体化温度和时间、等温淬火温度及时间等工艺参数进行优化分析,研究不同工艺参数下该型材的组织及硬度的变化规律.结果表明,等温淬火温度和奥氏体化温度是影响合金硬度的主要因素,随着二者温度的升高,基体组织中残留奥氏体量增多,硬度逐渐减小.试验用型材在现有的热处理参数中,硬度最高的工艺为840℃×60 min奥氏体化+280℃×100 min等温淬火,在此工艺条件下可以得到由细密贝氏体型铁素体与少量残留奥氏体组成的组织,型材硬度为476 HBW.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries.     

INTRODUCTION TO PATENTS

The invention provides a method of making a mold which can reduce SOx generation rate while preventing decrease in hardening rate in the case of using sulfuric acid for a hardener composition. The method has a mixture step in which fire-resistant particles, a hardener composition and a binder composition are mixed to obtain a composition for a mold. The hardener composition contains sulfuric acid. In the mixture step, sodium carbonate is added. A molar ratio of the sulfuric acid to the sodium carbonate is 0.5 or more and 4.0 or less.     

China Foundry Week 2014

China Foundry Week, hosted by the Foundry Institution of Chinese Mechanical Engineering Society （FICMES） each year, is a large academic event in China. It is one of the ten high-impact activities sponsored by the Chinese Mechanical Engineering Society.     

17th Conference of Hydrodynamic and Electromechanical Control Engineering Call for papers

正1.Contents In order to promote the academic exchanges and technical communication of the research in the field of fluid power transmission and control,fluid control engineering specialized committee of the Chinese Society of Theoretical and Applied Mechanics will hold the 17th Conference of Hydrodynamic and Electromechanical Control Engineering on July 27-29,2014 in Tibet,Lhasa city.     

Information for Contributors

正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis     

Preface

<正>We are pleased to present this Special Issue of Transactions of Nonferrous Metals Society of China containing selected papers from the First Asian Conference on Aluminum Alloys(ACAA-2013),held in Beijing,China,13–17 October 2013.This conference has been initiated,with approval of     

Information for Contributors

The Transactions of Nonferrous Metals Society of China, founded in 1991 and sponsored by The Nonferrous Metals Society of China, is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology, including mineral processing, extraction metallurgy, metallic materials and heat treatments, metal working, physical metallurgy, powder metallurgy, with the emphasis on fundamental science. It is the unique preeminent publication in English for scientists, engineers, under/post-graduates on the field of nonferrous metals industry. This journal is covered by many famous abstract/index systems and databases such as SCI Expanded, Ei Compendex Plus, 1NSPEC, CA, METADEX, AJ and JICST.     

Formulas of Tension of Continuous Rolling Process

The development of computer controlled continuous rolling process calls for a mathematical expression that can express the inequality condition of "constant flow". Tension is the link of the continuous rolling process. From the condition of dynamic equilibrium, a differential equation of tension is given out. On the basis of the physical rules established from the industrial practice and experimental studies, the law of volume constancy, the linear relation of forward slip and tension, the state equation of continuous rolling, the formula of dynamic tension, and the formula of static tension have been obtained. These formulae reflect the functional relations between tensions, thickness, roll velocity, and time in the continuous rolling process. It is implied that the continuous rolling process is a gradually steady, controllable, and measurable dynamic system. An assumption of predicting the thickness of a steel plate using these tension formulae is also put forward.