锤锻车间噪声特征分析及降噪措施

论述了噪声对人体的危害,研究了锤锻车间噪声现状及降噪措施。通过对锤锻车间现有噪声水平监测、作业人员工作日接噪剂量检测,将检测结果与相关噪声标准进行对比分析,发现锤锻车间现有噪声水平比国家标准高,需要进行噪声治理。通过在空气锤上安装阻性消声器、将排气管道通入地下等措施有效减低锻锤运行噪声。将3台燃气炉集中供风改造为变频风机单台供风,风机噪声由110 dB(A)降低至79 dB(A)。对燃气炉进行优化设计及改造,燃气炉噪声由改造前85 dB(A)降低至75 dB(A)。另外从设备改造、选用低噪声设备、以压代锻、自动化远距离操作等方面提出了可行降噪措施。     

汽轮给水泵机组振动噪声研究

汽轮给水泵机组的减振降噪是个难度较大的系统工程。本文对某汽轮给水泵机组的振动噪声激励源进行了分析,并对给水泵、汽轮机和机组其它部件的减振降噪设计思路和控制措施进行了阐述。     

圆锥滚子轴承实现减振降噪的方案措施

对圆锥滚子噪声的产生进行分析和分类,提出实现圆锥滚子减振降噪的措施,措施均在相关企业进行了验证,效果良好,已进入市场。同时,分析了圆锥滚子轴承振动并产生噪声的原因,区分了10类噪声的形成和特点,最后提出了圆锥滚子轴承实现减振降噪的措施。     

电液压清砂的隔振

我厂选用110型钢丝网减振器(见图1)对电液压清砂设备进行减振。这种目前尚未广泛应用的而又比较先进的减振器,具有稳定性好、安装方便、不产生疲劳和老化、可以长久使用等优点。安装后经反复试验,隔振效果十分满意,在离开水箱一米处没有振动感觉,经仪器测量振动噪声在隔振前后相差37dB(A)。     

潜艇液压系统管路振动与噪声的分析控制

液压管路噪声是“安静型”潜艇噪声的一个重要来源,有效控制液压系统管路振动与噪声是潜艇实现安静化的重要环节.分析了潜艇液压系统管路振动与噪声产生的原因,并从机械和流体动力噪声两个源头入手,提出控制管路振动与噪声的方法,能较好地达到减振降噪的目的.     

泡沫铝阻尼塞在齿轮传动中的减振降噪特性的研究

为了探讨齿轮减振降噪的新途径,对齿轮传动过程中振动噪声产生的机理进行分析,建立齿轮/阻尼塞系统振动的数学模型。根据泡沫铝材料的结构和性能特点,提出利用泡沫铝制造阻尼塞以达到对齿轮减振降噪的观点,并分析了泡沫铝齿轮阻尼塞与传统材料阻尼塞相比所具有的优越性。该成果为泡沫铝在齿轮减振降噪中的应用提供了一定的理论依据,对拓宽泡沫铝的应用具有一定的理论意义。     

数控转塔冲床减振降噪技术的研究

运用数值仿真方法对数控转塔冲床进行了动力学分析,并采取了机身结构优化设计、模具弹簧参数优选和静音冲裁模式等三种减振降噪措施。对改进前后机床的振动和噪声进行了测试和对比,测试结果表明减振降噪效果明显。本文能够为数控转塔冲床的新产品研发及技术改进提供参考。     

数控转塔冲床动态特性研究

数控转塔冲床的重载、高速化带来了振动和噪声加剧问题。本文以T30型数控转塔冲床为例,运用有限元法进行了模态分析和300kN打桩工况下的动态响应分析,其方法和结论能够为数控转塔冲床的减振降噪提供参考。     

滚子链传动系统的减振降噪研究

链传动是机械行业中应用非常广泛的一种传动机构,但它产生的振动和噪声具有很大的破坏作用.在分析链传动振动和噪声来源的基础上,提出了链轮齿形的修正方法,分析了采用修形链轮减振和降噪的机理.对由修形链轮组成的滚子链传动系统和标准滚子链传动系统分别进行了多体系统动力学仿真分析.结果表明采用修形链轮有利于减小链传动过程中的啮入冲击和多边形效应,因而能够有效减小链传动过程中的振动和噪声.     

基于钢球振动所产生的轴承噪声数学模型

利用声学理论中的振动球源建立了，由轴承钢球振动所产生的噪声数学模型，为研究滚动轴承的降噪减振提供了理论依据。同时根据现场的试验情况，对该数学模型进行了验证，其结果是可行的。     

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.