高速钢刀具的深冷与QPQ的复合处理

深冷处理能有效提高高速钢刀具的基体强度,而QPQ工艺则可提高其表面耐磨性,用这两种方法对高速钢刀具进行复合处理将明显提高刀具的使用寿命。     

高速钢刀具表面PCVD复合渗镀强化研究

利用PCVD复合渗镀技术对W6Mo5Cr4VZ(MZ)高速钢刀具进行表面强化处理,研究PCVD复合渗镀处理前后高速钢刀具的表面硬度、摩擦磨损性能和抗氧化性能。结果表明,经PCVD复合渗镀处理后,W6Mo5Cr4VZ(MZ)高速钢刀具的表面硬度明显提高,磨损性能大幅改善。表面强化层优异的抗氧化能力和强韧性提高了刀具的切削性能。     

深冷处理对高速钢红硬性及耐磨性的影响

研究了深冷处理对Ｗ１８Ｃｒ４Ｖ和Ｗ６Ｍｏ５Ｃｒ４Ｖ２高速钢红硬性及耐磨性的影响。试验结果表明，深冷处理不仅可提高速钢的室温硬度，同时可明显改善高速钢的红硬性和耐磨性，延长高速钢刀具的使用寿命。     

近年来关于陶瓷结合剂CBN砂轮的研究及成果

本文介绍了近年来开发陶瓷结合剂ＣＢＮ砂轮磨削汽车发动机凸轮轴，高速钢刀具、锯片端面，轴承内表面等取得的成果。     

工模具钢深冷处理探讨

钢或合金在0～—－100℃的处理，称为普通冷处理（简称冷处理）；在—130℃以下的处理，称为深冷处理。通常认为，工具钢采用冷处理，主要是使残留奥氏体充分转变，以提高钢的硬度和稳定零件尺寸。但是，对提高高速钢刀具切削寿命无明显效果，放高速钢刀具很少采用冷处理。70年代后期报道了：将高速钢淬火刀具或成品刀具，自室温浸入一196C液氮，进行急速冷却的深冷处理，能成倍提高刀具寿命。这一方法引起人＊敞兴趣和注意，并广泛进行了试验研究。试验的钢种有各种高速钢、碳工具钢、低合金工具钢和高合金工具钢，试验的工具类型有各种规…     

高速钢刀具表面PCVD复合渗镀强化研究

利用PCVD复合渗镀技术对W6Mo5Cr4VZ(MZ)高速钢刀具进行表面强化处理。研究了未处理及PCVD复合渗镀处理高速钢刀具的表面显微硬度,分析了PCVD前后高速钢刀具的摩擦磨损性能及试样镀层与基体结合力的不同,对PCVD处理前后镀层抗氧化能力进行了初步分析,利用SEM扫描电镜对刀具处理部位进行分析。实验结果表明:经PCVD复合渗镀处理后,W6Mo5Cr4VZ(MZ)高速钢刀具表面硬度显著提高,磨损性能大幅改善;强化层优异的抗氧化能力及强韧性很好地提高了刀具的切削性能,扫描电镜分析发现PCVD处理试样断口形貌较为平整,强化层与基体清晰可见。     

高速钢刀具材料及热处理工艺选择

0　引言高速钢自诞生以来 ,作为机械加工中切削刀具的最基础用材料一直被广泛采用 ,目前 ,高速钢刀具仍占据着刀具市场的主导地位。尽管镶片硬质合金刀具、全磨制硬质合金刀具的发展十分迅速 ,但除车刀外 ,其它品种刀具仍以采用高速钢材料制造为主。高速钢按最终冶炼方法的不同可分为电孤炉冶炼高速钢、中频感应炉冶炼高速钢、电渣重熔冶炼高速钢、粉末冶金高速钢等。对于高速钢刀具而言。尽管存在高速钢冶炼方式的差异 ,但刀具的耐用与否 ,更直接地与高速钢的化学成分以及通过合理的热加工处理、使其建立起“化学成分_组织结构_机械性能”…     

高速钢低温渗碳及复合处理工艺研究

研究了Ｗ１８Ｃｒ４Ｖ高速钢在５５０℃下的低温固体渗碳工艺及低温渗碳＋深冷复合处理工艺。结果表明，与淬火回火态高速钢相比，经低温渗碳及复合工艺处理后硬度，红硬性得到改善，刀具的耐用度明显提高。     

粉末冶金高速钢

高速钢是一种具有高硬度、高耐磨性和高耐热性的工具钢,500℃仍能保持高的硬度,且强度和韧性配合好,可以用来制造复杂的薄刃和耐冲击的金属切削刀具,也可制造高温轴承和冷挤压模具等。粉末冶金高速钢是采用粉末冶金工艺制备的高速钢,碳化物呈极细小的颗粒均匀地分布于基体,避免了熔炼法生产所造成的碳化物偏析而引起力学性能降低和热处理变形,能够大幅度提高其使用寿命。     

无Co高硬及超硬高速钢

由于被加工工件硬度的提高以及加工中心和数控机床的广泛应用，用硬度为65HRC的通用高速钢M2制作的刀具已不能满足要求。需要用硬度高的高硬及超硬高速钢制造刀具。     

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.