杯形薄壁梯形内齿旋压件的制取及金相组织的研究

内齿旋压成形是一种新型的齿轮制造技术,对内齿旋压件成形组织性能的研究不但能丰富旋压成形理论,而且对于指导内齿旋压生产、降低产品的试制成本和提高旋压设备利用率都具有重要意义。本文阐述了内齿旋压用毛坯及内齿件的制取方法,并对原始板坯、内齿旋压用杯形预制坯及内齿旋压件的金相组织进行了分析比较。结果表明,与切削加工不同,旋压成形后,齿轮件出现明显的纤维组织并形成变形织构,使其力学性能得到显著提高。     

旋压成形对内齿轮显微组织的影响

为了分析旋压成形技术对内齿轮显微组织的影响,采用LEICA DMIRM大型金相显微镜和LEICA Q550MU图像分析仪研究了内齿轮旋压件的金相组织.分析表明,旋压成形后内齿轮的金属材料组织与毛坯的金属材料组织相比形貌改善非常明显,晶粒得到明显的细化；通过旋压技术可以有效提升内齿轮的强度和韧性.     

齿轮参数对杯形薄壁内齿旋压成形的影响

杯形薄壁内齿轮的旋压成形技术是近年来发展起来的新技术,采用该技术成形的内齿零件主要包括内花键和内齿轮.为了分析齿轮参数对杯形薄壁内齿旋压成形的影响,本文采用工艺试验的方法,对梯形内花键和渐开线内齿轮旋压成形进行了研究.结果表明:齿数的增加将导致制件内侧出现缩径;齿根处齿厚的增加,有利于材料的径向充填,不利于材料的切向充...     

工艺参数对杯形内啮合齿轮旋压成形影响的数值模拟研究

基于金属塑性变形原理和旋压工艺的特点,提出杯形薄壁内啮合齿轮旋压成形技术,建立了齿轮旋压三维弹塑性有限元模型并进行了数值模拟,分析了齿轮旋压成形中各变形区不同方向应变分布和金属流动规律,定性地分析了主要工艺参数对齿轮旋压成形的影响规律。结果表明,压下量对齿轮成形起关键作用,并对齿根减薄影响大于齿顶增厚的影响,进给比对齿轮成形影响不大,大的旋轮圆角半径有利于齿顶增厚。该项研究为提高生产效率、优化产品质量提供了理论依据,同时也为进一步研究齿轮旋压技术奠定了坚实基础。     

旋压技术在内齿轮制造中的应用及展望

叙述了国内外的主要齿轮加工方法，引出常用内齿轮的加工方法，进一步介绍旋压技术在内齿轮中的应用，重点介绍杯形薄壁矩形内齿旋压成形工艺的成形机理，并说明了采用旋压技术来成形杯形薄壁矩形内齿轮是合理可行的。     

工艺参数对杯形内啮合齿轮旋压成形影响的数值模拟研究

基于金属塑性变形原理和旋压工艺的特点,提出了杯形薄壁内啮合齿轮旋压成形技术,建立了齿轮旋压三维弹塑性有限元模型并进行了数值模拟,分析了齿轮旋压成形时各变形区不同方向应变分布和金属流动规律,定性分析了主要工艺参数对齿轮旋压成形的影响规律。结果表明,压下量对齿轮成形起关键作用,并对齿根减薄影响大于齿顶增厚的影响,进给比对齿轮成形影响不大,大的旋轮圆角半径有利于齿顶增厚。     

框架式三旋轮错距旋压成形装置的研制

采用分层错距进行旋压成形时，工件厚度逐渐减小，增大了道次减薄率，减少了加工道次，可显著提高旋压件的加工精度和生产效率。本文根据齿轮旋压成形工艺要求、旋压成形原理及三旋轮错距旋压工艺特点，设计了一种框架式三旋轮错距旋压成形装置，重点介绍了旋轮座、旋轮径向进给及轴向、径向错距量调整等结构的设计方案，并对蜗杆传动进行了强度设计。     

带内齿工件的旋压成形

介绍了用旋压成形工艺方法来生产带内齿零件如汽车离合器壳体，行星齿轮内齿。本工艺节省材料，提高精度，强度，硬度，提高生产效率，降低生产成本。     

成形工艺参数对三维非轴对称零件旋压成形质量的影响

对铝合金旋压件旋压前后的金相组织进行了对比,分析了不同非轴对称旋压方式(偏心和倾斜)下旋压件的硬度变化。结果表明,旋压后变形部分金属晶粒细化,并沿着轴向方向变形拉长,旋压件强度指标提高,维氏硬度明显提高;旋压件的硬度随着名义压下量的增加而增加;成形时毛坯向0°域偏心或倾斜,在0°域处硬度最大,在180°域处硬度最小,在90°域与270°域处硬度相当;随着偏心量及倾斜角的增加,其硬度增加。     

6061合金特种筒件旋压工艺及组织性能研究

在2 m立式旋压机上,采用正、反旋相结合的成形工艺,制备了6061铝合金特种筒形件;分析了其变形前、后组织与性能的变化.试验结果表明,旋压成形获得了所需尺寸规格的特种筒形件,旋压变形后其显微组织细小均匀,综合力学性能得到提高.     

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.     

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.     

Mechanism of Nucleation of Precipitates of Carbides of Refractory Metals Under Hot Rolling of Automotive Sheet Steel

Metal Science and Heat Treatment - The problem of formation of properties in microalloyed sheet steels is considered. The cause and the possible mechanism of precipitation of carbides of refractory...     

燃煤机组锅炉烟气脱硝灰中氨含量测定

NOx是大气环境的主要污染物之一,其主要来源为火力发电机组。依靠低氮燃烧技术,远达不到排放要求。选择性催化还原脱硝(简称SCR)技术是目前效率最高、最成熟、应用最广泛的电厂烟气脱硝技术。目前,在线氨逃逸监测技术存在诸多问题,影响了氨逃逸监测数据的准确度和稳定性。在燃料种类、炉膛结构、受热面布置、过量空气量、炉膛气流分布以及脱硝催化剂类型等条件确定的情况下,控制好氨加入量及其逃逸量是保证NOx脱除率的关键所在。燃煤锅炉除尘飞灰氨含量可侧面反映脱硝氨逃逸率的状况。根据国外的文献报道,正常情况下,电除尘灰中氨含量一般在50mg/kg-100mg/kg范围内。由于国内尚无灰中氨含量的测定方法,亦无脱硝运行对飞灰含氨量影响的数据积累。本文通过大量试验,确定了灰中氨溶解条件(如溶解时间、搅拌状态、灰水比、灰样量及其稳定性等),制定了灰中氨含量测定方法。     

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.