带凸缘齿轮的胎模锻造

为提高小型锻造厂小批量生产不同尺寸的带凸缘齿轮毛坯生产效率,提高锻件质量,介绍了压槽-展宽胎模锻造工艺和双向垫环镦挤胎模锻造工艺.这对小型锻造厂生产同类型毛坯起借鉴、指导作用.     

双边支重轮的翻边锻造

履带式推土机双边支重轮纵向有内孔贯通,横向有环状凹槽,该件不论模锻还是胎模锻,均不可一次锻造成形。本文从工艺上、模具结构上详细介绍了由5t模锻锤锻中间毛坯,3t自由锻锤胎模翻边成形的联合锻造工艺。     

通孔类锻件的胎模锻造

由于胎模锻较模锻具有众知的工艺操作灵活、可局部成形、可改变制坯程度、生产周期短、成本低等优越性,加之我厂模锻设备欠缺,因此对于具有通底内孔的对称形锻件即通孔类锻件大都采取胎模锻的方式生产.下面将介绍在实践中得到的一些体会,对通孔件胎模锻的工艺特点及模具结构特点作一小结,并指出生产中应注意的一些问题.     

一种锻造齿套的新型胎模

<正> 汽车变速器中的齿套零件(图1),一般是采用模锻的方法生产,其模锻件在内外径方向都有模锻斜度(图2)。没有模锻设备的工厂,则多数采用胎模锻的方法。胎模锻件一般在外径方向没有模锻斜度,而在内径方向仍有模锻斜度(图3)。我厂原来生产的齿套锻件也和图3一样。为了取消锻件上的模锻斜度,达到节约金属材料、减少机械加工工时和降低锻件成本的目的,我们设计了一种新的胎模(图4、图5)。利用这     

大活塞的胎模锻造工艺

介绍了大活塞胎模锻成形工艺，分析了影响大活塞锻造成形的各种不利因素，在工艺制订及模具制做上采取了相应的措施，为小设备干大活以及同类产品的锻造生产提供了参考依据。     

大头小杆形凸肩齿轮胎模锻的合理方法

从锻造工艺技术角度，讨论了提高大头小杆或大头细杆凸肩齿轮锻件的内在质量和有利于锻件成形胎模锻的合理方法。同时介绍了拔镦法、镦拔法、镦挤法和镦拔挤复合法胎模锻的适用范围、原材料规格与中间坯料形状尺寸的确定原则和胎模的设计原则，及其应用实例。     

一种锻造齿套的新型胎膜

汽车变速器中的齿套零件(图1),用模锻法生产,其锻件内外径方向都有模锻斜度(图2),用胎模锻法生产,其锻件一般在外径方向无斜度,而在内径方向仍有斜度(图3)。我厂原来生产的齿套锻件也和图3一样。为了取消锻件上的模锻斜度,达到节约金属材料、减少机械加工工时和降低锻件成本的目的,我们设计应用了一种新的胎模(图4、图5)。其锻件     

大型磨辊轴锻造新工艺

大型磨辊轴锻件外形特殊,法兰形状为矩形,且法兰与相邻台阶截面差大,在锻造时受设备能力、钢锭锭型限制,生产组织困难。本文利用Deform模拟软件对磨辊轴胎模锻造工艺进行研究,探索出了一种实用仃效的工艺方案。     

基于自由锻的细长栓杆胎模锻造法

本文根据锻造生产中的典型实例,论述基于自由锻-空气锤胎模锻造细长栓杆的方法,对细长栓杆的锻造胎模进行设计,并阐述细长栓杆胎模锻造工艺过程,同时,针对锻造生产过程中容易出现的问题进行分析说明,以便合理利用现有锻造设备,解决设备不足对生产带来的影响。     

锥台类零件成形工艺研究

针对小批量锥台类锻件成形中存在的轴向推力问题,提出了切肩成形锥台、胎模锻终锻成形的工艺方案,材料利用率提高了30%。运用DEFORM-2D软件对胎模锻成形过程进行模拟,验证了方案的可行性。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

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 Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Quantitative Analysis of the Crystallographic Orientation Relationship Between the Martensite and Austenite in Quenching–Partitioning–Tempering Steels

The orientation relationships(ORs)between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction(SAED)as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_(bcc).A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.     

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.     

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.