渗碳淬火行星齿轮内孔畸变控制

针对某行星齿轮在渗碳淬火过程中内孔畸变严重的问题,采取了等温正火、降低渗碳温度和改变齿轮渗碳摆放方式等措施。经检测表明,采用改进工艺处理后,行星齿轮成品表面硬度和心部硬度分别为60.4~61.8 HRC和41.8 HRC,符合产品技术要求;内孔椭圆度和公法线长度变动量均100%合格;垂直摆放为最佳渗碳摆放方式。     

工业机器人用SCM420钢行星齿轮热处理工艺的优化

针对工业机器人用SCM420钢制行星齿轮热处理畸变问题,采用改进的正火工艺以调整渗碳前的预备组织,并设计合理的装料方案和冷却方式等措施,同时在渗碳过程中采用阶梯升温的工艺,有效地控制了渗碳淬火过程中齿轮畸变。结果表明,采用优化正火后可得到均匀一致的铁素体+珠光体的组织,硬度为175 ~180 HBW。随后经渗碳淬火回火后,批量生产的行星齿轮表面硬度、心部硬度和有效硬化层深度均值分别为59.74 HRC、40.44 HRC和0.530 mm。渗碳层中的马氏体级别为1级,残留奥氏体和碳化物级别为1~2级;心部组织级别为1~2级。齿轮精度、平面翘曲、齿沟振幅和齿形齿筋等全部满足技术要求。     

20Cr2Ni4A钢渗碳/感应热处理工艺应用

20Cr2Ni4A钢零轴驱动齿轮采用传统渗碳/整体淬火工艺处理,基体硬度在45 HRC左右,内孔花键插削困难,合格率仅为50%左右。为解决此问题,设计了2种渗碳/感应热处理工艺方案。结果表明:采用渗碳/感应淬火表面强化工艺,在保证渗碳齿面硬度合格的基础上,能稳定控制基体硬度在37 HRC左右,解决了内孔花键插削困难的问题,提高了产品合格率。     

减小齿轮渗碳淬火后花键孔变形的工艺措施

对经渗碳淬火后内花键孔变形收缩的齿轮 ,长期以来都是用推刀进行扩孔修复 ,既费时 ,推刀的消耗量也大 ,质量还难以保证。我们曾想法对推刀进行处理来提高其使用寿命 ,也曾摸索用套花键轴等方法来控制齿轮渗碳淬火花键孔变形 ,但最为有效的方法是改进渗碳淬火工艺。我们对拖拉机齿轮应用稀土渗碳工艺配合使用好富顿淬火介质来减小其渗碳淬火花键孔变形 ,经大量的生产验证 ,效果很好。现以拖拉机末端传动、被动齿轮为例作一介绍。1　工艺改进情况齿轮材料为 2 0 Cr Mn Ti,M=3.5,Z=52 ,要求其表面硬度 58～ 6 4 HRC,心部硬度大于 38HRC,…     

减少大行星齿轮渗碳淬火畸变的工艺措施

我公司生产的154t电动轮自卸车上的大行星齿轮(见图1)，材料为20Cr2Ni4A钢，要求齿面渗碳淬火，渗碳层深1．9～2．3mm，齿面硬度58～63HRC，心部及其它表面硬度35～45HRC，端面平面度≤0．6mm。     

齿轮淬火变形的控制

EQ－140汽车后桥被动齿轮是双曲面齿轮，其热处理质量和尺寸精度的技术要求很高，包括渗碳层深度1．5～1．9mm，碳化物1～6级，马氏体、残留奥氏体1～5级，心部铁素体1～5级，齿面硬度58～63HRC，心部硬度33～48HRC，热处理后产品的内缘不平度不大于0.20mm，外线不平度不大于0．12mm，内孔椭圆度不大于0.12mm，内径变化范围不大于±0.16mm。在生产中，本厂EQ－140汽车后桥被动齿轮是由井式气体渗碳炉渗碳后直接淬火的，其变形包括齿轮内孔的涨大和收缩，内孔失圆和内、外缘翘曲以及齿条公法线伸长和缩短等，与齿轮在淬火过程中各部位冷…     

地铁驱动齿轮渗碳淬火畸变控制及性能

对地铁驱动齿轮渗碳淬火后的畸变及性能进行了研究。结果表明:经合适的渗碳淬火工艺处理后,齿轮有效硬化层深1.60 mm,表面硬度58.0~59.0 HRC,心部硬度39.0~40.5 HRC,均较好地满足技术要求。采用专用工装夹具及合理的装夹方式,可有效控制齿轮的畸变,保证产品的稳定性。     

重载汽车20CrMnMo齿轮激光淬火热处理工艺

为研究20CrMnMo齿轮经激光淬火后的硬度值和微观组织以及与其他热处理方式相比的差异,采用"渗碳淬火"和"渗碳后不同参数的激光淬火"等工艺方法处理了一批齿轮;测定其齿面硬度值并对数据进行Matlab软件分析;采用扫描电子显微镜(SEM)对典型试样进行显微组织观察;测定和分析部分试样的晶粒度。结果表明:"渗碳后激光淬火"齿面的硬度值最高可达61.4 HRC,比渗碳淬火齿轮高2.3 HRC左右;渗碳后激光淬火的高硬度值试样的微观组织为致密的针状马氏体与板条状马氏体的混合,晶粒度为9级左右,有熔融现象的试样微观组织为回火索氏体,且不同激光参数处理的试样其微观组织类型和尺寸差别较大。因此20CrMnMo齿轮可以通过渗碳后的激光淬火工艺获得较高的硬度值、较好的微观组织和晶粒度。     

轻型车后桥圆锥齿轮渗碳淬火变形的控制

如何提高轻型车后桥圆锥齿轮的对研合格率一直是各生产厂家所关心的话题。几年来 ,我们通过不断地探索 ,积累了一定的经验。本文从热处理角度探讨如何通过控制渗碳淬火变形 ,提高齿轮的热处理质量 ,从而提高齿轮的对研合格率。现以轻型车后桥圆锥从动齿轮为例作一介绍。1　工艺改进情况齿轮材料为 2 0 Cr Mn Ti,M=5 ,Z=41,要求其表面硬度 5 8～ 64HRC,心部硬度 3 3～ 48HRC,渗碳层深0 .9～ 1.3 mm。渗碳设备为 UBE-60 0箱式炉 ,装炉量96件 /炉。齿轮热处理后允许变形量 :1内孔 :12 5 .5 0 .2 00mm,圆度公差≤ 0 .0 5 mm;2平面度公…     

变速器从动齿轮的热处理工艺改进

图1为某汽车变速器一档从动齿轮示意图,其材料为20CrMoH钢,技术要求表面硬度(82±2)HRA,心部硬度30～43 HRC,有效硬化层深度0.5～0.7 mm,显微组织检验按HB 5492-1991<航空钢制件渗碳、氮碳共渗金相组织检验标准>进行,热处理后周节累计误差≤0.04 mm.齿轮加工工艺路线;锻造-等温正火-粗车-精车-滚齿-剃齿-渗碳淬火、回火-清理抛丸-精磨内孔-装机使用.齿轮渗碳淬火、回火处理后的齿形、齿向、周节累计畸变大,致使在装配试车过程出现齿轮接触精度低,噪声大的故障.因此,改进渗碳淬火工艺及装炉方式,控制热处理后的畸变量,是提高齿轮接触精度降低噪声的关键.     

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.     

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.     

The Mirror with Patterns of Auspicious Animals and Grapes——Exquisite cast mirror and the technology of surface tin-enrichment by rubbing-in and infiltration of tin-rich powder

<正>Bronze mirrors were used by the Chinese people before the introduction of the glass mirror.Only after it was replaced by the glass mirror did the bronze mirror gradually retreat from people's lives.Different styles of bronze mirrors were made in different historical periods,particularly in the Warring States Period,the Han and Tang Dynasties,which were the three peaks of the development of bronze mirror arts in ancient China.The casting techniques were exquisite.The surface of the bronze mirror was smooth and bright enough to reflect one's image,and there were scarcely any casting defects on the mirror surface.On the back of the bronze mirror,there were rich depictions of Arts and Humanities,and the ornamentations were also     

The 9th China International Diecasting Congress & Exhibition

The 9th China International Diecasting Congress ＆ Exhibition was held on July 22-24, 2014 at Shanghai New International Expc Centre. This exhibition was the most successful over the years, with over 6890 visitors and 155 exhibitors, and the exhibition area increased by 30% from 9,500 square meters in 2012 to 12340 square meters. Die casting enterprises from a total of 24 countries and regions, including China mainland, Chinese Taiwan and Hong Kong, South Korea, Japan, Germany, India, Thailand, Malaysia, the United States, Russia, Australia, Iran, Ukraine, Brazil, Colombia, Singapore, Austria, Canada, Croatia, France, Turkey, United Kingdom, Vietnam, attended the congress and exhibition.     

Introduction of the Fluid Control Engineering Institute of Kunming University of Science and Technology

正The Fluid Control Engineering Institute of Kunming University of Science and Technology was set up in 1996.The researches of institute concentrate on electro-hydraulic(pneumatic)servo/proportional control and hydromechatronics.The Institute is committed to research and development of electro-hydraulic control of high-end technical equipment in ferrous metallurgy refining produc-     

RARE METALS Volume Contents

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Antimony Induced Crystallization of Amorphous Silicon

Antimony induced crystallization of PVD (physics vapor deposition) amorphous silicon can be observed on sapphire substrates. Very large crystalline regions up to several tens of micrometers can be formed. The Si diffraction patterns of the area of crystallization can be observed with TEM (transmission electron microscopy). Only a few and much smaller crystals of the order of 1μm were formed when the antimony layer was deposited by MBE (molecular beam epitaxy) compared with a layer formed by thermal evaporation. The use of high vacuum is essential in order to observe any Sb induced crystallization at all. In addition it is necessary to take measures to limit the evaporation of the antimony.     

A CUMULATIVE FATIGUE DAMAGE RULE UNDER THE ALTERNATIVE OF CORROSION OR CYCLIC LOADING

Fatigue damage increases with the applied loading cycles in a cumulative manner and the material deteriorates with the corrosion time. A cumulative fatigue damage rule under the alternative of corrosion or cyclic loading was proposed. The specimens of aluminum alloy LY12-CZ soaked in corrosive liquid for different times were tested under the constant amplitude cyclic loading to obtain S-N curves. The test was carried out to verify the proposed cumulative fatigue damage rule under the different combinations among corrosion time, loading level, and the cycle numbers. It was shown that the predicted residual fatigue lives showed a good agreement with the experimental results and the proposed rule was simple and can be easily adopted.