机械类英语文章
机械专业类英语文章阅读
机械专业类英语文章阅读篇一：机械专业英语作文1Mechanical engineeringEngineering Science in life are widely used, especially in mechanical engineering in the application of life is almost throughout life in all its aspects, to automobiles, aircraft, small electric fans, umbrella, all of these and related machinery. The project includes many subjects, but the mechanical engineering is one of the most important subjects, not only because of our life and itis closely related to, but with the progress of the times, people have to rely on mechanical engineering products, in automation today, machine instead of many this is the part of the human labor, improve the efficiency and save time.As a result of mechanical engineering in every aspect of life, therefore, as an engineer, be faced with a great many challenges, in addition to a solid with knowledge, but also keep pace with the times, familiar with the machinery and related software, can be very good use of software, and as a an engineer, we should try our best to design and produce and closely related to the life of the machine, and can in life play a real role, also have only such, we address and remission now social needs, therefore, the mechanical engineering in the future social development, will play the important role, especially China s case, the industry also is not very developed, machinery can be greater development space.Before the industrial revolution, machinery is mostly wood structure, wood made by hand by. The development of social economy,the demand for mechanical products. The bulk of the production increasing and precision processing technology progress, promote the mass production method ( interchangeability of parts production, professional division of labor and cooperation, water processinglines and assembly lines ) formation. Study of mechanical products in the manufacturing process, especially when used in the pollution of the environment and natural resources excessive consumption problems and their treatment measures. This is a modern mechanical engineering is an especially important task to grow with each passing day, andits importance.Application of mechanical products. This includes selection, ordering, acceptance, installation, adjustment, operation, maintenance, repair and transformation of the industrial use of machinery and complete sets of machinery and equipment, to ensurethat the mechanical products in the long-term use of reliability and economy.As a student, we are now the most important to learn professional knowledge, only in this way, can we later life and learning, to doits part.机械工程工程科学在生活中应用广泛，特别是机械工程在生活中的应用几乎就是遍布了生活中的各个方面，大到汽车、飞机，小到电风扇、雨伞，这些都和机械有关。
机械专业英语作文
机械专业英语作文In the realm of engineering, mechanical engineering stands as one of the oldest and most fundamental disciplines. It is the branch of engineering that deals with the design, analysis, manufacturing, and maintenance of mechanical systems. This essay will delve into the evolution of mechanical engineering, highlighting its historical milestones, the impact of technological advancements, and the challenges and opportunities it faces in the modern world.Early BeginningsMechanical engineering has its roots in the ancientcivilizations of Mesopotamia, Egypt, and China, where early engineers developed simple machines such as levers, pulleys, and gears. The Greeks, notably Archimedes, contributed significantly to the field with the development of the screw pump and other mechanical devices.Industrial RevolutionThe Industrial Revolution marked a significant turning point for mechanical engineering. With the invention of the steam engine by James Watt, the world saw a shift from manual labor to mechanized production. This period also saw the development of textile machinery, locomotives, and various other machines that laid the foundation for modern industry.20th Century InnovationsThe 20th century brought about a plethora of innovations in mechanical engineering. The internal combustion engine revolutionized transportation, while the development of electric motors and power generation systems transformed the energy sector. The advent of computer-aided design (CAD) and computer-aided manufacturing (CAM) systems in the latter half of the century further streamlined the design and manufacturing processes.Modern ChallengesToday, mechanical engineers face new challenges such as sustainability and energy efficiency. The need for greener technologies has led to the development of hybrid andelectric vehicles, renewable energy systems, and energy-efficient machinery. Additionally, the field is grappling with the integration of artificial intelligence and robotics, which promise to automate and optimize manufacturing processes.Future ProspectsLooking ahead, mechanical engineering is poised to play a crucial role in shaping the future. Advancements in nanotechnology, materials science, and biotechnology are expected to lead to breakthroughs in areas such as nano-robotics and bio-mechanical systems. Furthermore, the rise of Industry 4.0, characterized by the fusion of the digital and physical worlds, will continue to redefine the scope andcapabilities of mechanical engineering.ConclusionMechanical engineering has come a long way from its rudimentary beginnings to become a cornerstone of modern society. As technology continues to evolve, the role of mechanical engineers in creating innovative solutions to global challenges will only grow in importance. The future of mechanical engineering is as promising as it is exciting, with endless possibilities for those who dare to innovate and lead.。
机械类相关英语文章精选
机械类相关英语文章精选在发展传统机械工程技术的同时,在机械工程技术中还必须融入环境技术,走可持续发展的战略。
下面是店铺带来的机械类相关英语文章，欢迎阅读!机械类相关英语文章精选Dimension and Tolerance尺寸和公差In dimensioning a drawing, the numbers placed in the dimension lines represent dimensionthat are only approximate and do not represent any degree of accuracy unless so stated bythe designer.在图纸标注尺寸时,除非设计者有意标明,注在尺寸线上的数字代表的尺寸仅仅是近似的,并不代表任何精度等级。
To specify a degree of accuracy, it is necessary to add tolerance figures to the dimension.T olerance is the amount of variation permitted in the part or the total variation allowed in agiven dimension.为了详细标明精度等级,有必要在尺寸上增加公差数字。
公差是零件允许的变动量或给定尺寸允许的总变动。
A shaft might have a nominal size of 2.5in.(63.5mm), but for practical reasons this figurecould not be maintained in manufacturing without great cost. Hence, a certain tolerance wouldbe added and, if a variation of±0.003in.(±0.08mm) could be permitted, the dimension wouldbe stated 2.500±0.003(63.5±0.08mm).一根轴可能的名义尺寸为2.5in.(63.5mm),但由于实际原因不用大成本是不能在制造中保持这个数字的,因此要增加确定的公差。
机械专业介绍英语作文
机械专业介绍英语作文The field of mechanical engineering is a diverse and dynamic discipline that encompasses the design, development, and implementation of a wide range of mechanical systems and devices. As a mechanical engineering student, I have had the opportunity to delve into the intricacies of this fascinating field, and I am excited to share my insights with you.At the core of mechanical engineering is the understanding and application of fundamental principles of physics, mathematics, and materials science. Mechanical engineers utilize these principles to create innovative solutions to complex problems, ranging from the design of simple machines to the development of advanced technologies that power our modern world.One of the key aspects of mechanical engineering is the design process. Mechanical engineers are responsible for conceptualizing, designing, and optimizing the performance of mechanical systems and components. This involves the use of computer-aided design (CAD) software, finite element analysis (FEA) tools, and other advanced modeling and simulation techniques to test and refine their designs.Another crucial aspect of mechanical engineering is the manufacturing and production of mechanical systems. Mechanical engineers work closely with manufacturing teams to ensure that their designs can be effectively and efficiently produced. This may involve the selection of appropriate materials, the implementation of advanced manufacturing processes, and the development of quality control measures to ensure the reliability and durability of the final product.In addition to design and manufacturing, mechanical engineers are also involved in the operation and maintenance of mechanical systems. They may be responsible for troubleshooting and repairing equipment, optimizing system performance, and developing preventive maintenance strategies to ensure the long-term reliability and efficiency of mechanical systems.One of the most exciting aspects of mechanical engineering is the opportunity to work on a wide range of applications and industries. Mechanical engineers can be found in sectors such as aerospace, automotive, energy, healthcare, and manufacturing, among others. This diversity of applications allows mechanical engineers to apply their skills and knowledge to solve complex problems and contribute to the advancement of technology and society.As a mechanical engineering student, I have had the privilege of exploring various specializations within the field. For example, I have delved into the design and analysis of thermal systems, such as heating, ventilation, and air conditioning (HVAC) systems, as well as the development of advanced energy conversion technologies, such as wind turbines and solar power systems.I have also had the opportunity to work on projects that involve the design and optimization of mechanical components, such as gears, bearings, and linkages. These projects have allowed me to apply my knowledge of materials science, solid mechanics, and dynamic systems to create innovative solutions that improve the performance and reliability of mechanical systems.In addition to technical skills, mechanical engineers must also possess strong problem-solving, critical thinking, and communication abilities. Effective collaboration with cross-functional teams, including engineers from other disciplines, as well as with clients and stakeholders, is essential for the successful completion of projects.As I look to the future, I am excited about the potential of mechanical engineering to continue driving technological advancements and contributing to the betterment of our world. With the rapid pace of innovation and the growing demand forsustainable and efficient solutions, I believe that mechanical engineering will play an increasingly important role in addressing global challenges, such as climate change, energy security, and healthcare.In conclusion, the field of mechanical engineering is a dynamic and multifaceted discipline that offers a wealth of opportunities for those who are passionate about technology, innovation, and problem-solving. As a mechanical engineering student, I am proud to be part of a profession that is at the forefront of shaping the future and improving the quality of life for people around the world.。
机械专业英语文章中英文对照
机械专业英语文章中英文对照作为应用型人才培养的全日制机械工程专业学位研究生,除了具有扎实的理论基础以外,还需要满足机械行业的实际工作需求。
下面小编整理了中英文对照机械专业英语文章，希望大家喜欢!中英文对照机械专业英语文章品析公差系统A system of tolerances is necessary to allow for the variations in accuracy that are bound tooccur during manufacture, and still provide for interchangeability and correct function of thepart.为了允许在制造过程中必然会发生的精度变化并提供零件的互换性和正确功能一个公差系统是必需的。
A tolerance is the difference in a dimension in order to allow for unavoidable imperfections inworkmanship. The tolerance range will depend on the accuracy of the manufacturingorganisation, the machining process and the magnitude of the dimension.公差是为了允许工艺上不可避免缺陷而存在的尺寸上的不同。
公差范围取决于制造机构的精度、机加工过程和尺寸的量值。
The greater the tolerance range, the cheaper the manufacturing process. A bilateral toleranceis one where the tolerance range is disposed on both sides of the nominal dimension. Aunilateral tolerance is one where the tolerance zone is on one side only of the nominaldimension, in which case the nominal dimension may form one of the limits.公差范围越大则制造过程的成本就越低。
机械专业英语短文带翻译
机械工程师的关键责任之一是设计与分析机械系统。这涉及使用计算机辅助设计（CAD）软件创建系统的详细三维模型，并在不同条件下模拟其性能。通过分析作用于系统组件的力、应力和振动，机械工程师可以优化设计，确保安全、可靠和高效。
Case Study: Designing an Automotive Suspension System
案例研究：汽车悬挂系统设计
例如，让我们考虑一下汽车悬挂系统的设计。悬挂系统负责在保持车辆稳定控制的同时提供平稳的行驶。机械工程师使用CAD软件设计悬挂系统的各个组件，例如弹簧、减振器和控制臂。
在完成初始设计后，工程师将使用有限元分析（FEA）软件对系统进行分析。这样可以模拟系统在不同的道路条件下（如坑洼或减速带）的行为。通过分析组件中的应力和位移，工程师可以确定潜在的设计问题，并进行必要的修改，以改善悬挂系统的性能和安全性。
For example, let's consider the design of an automotive suspension system. A suspension system is responsible for providing a smooth ride while maintaining the stability and control of the vehicle. A mechanical engineer would use CAD software to design the various components of the suspension system, such as the springs, dampers, and control arms.
After the initial design is complete, the engineer would then analyze the system using finite element analysis (FEA) software. This allows them to simulate the behavior of the system under different road conditions, such as potholes or speed bumps. By analyzing the stresses and displacements in the components, the engineer can identify potential design issues and make necessary modifications to improve the performance and safety of the suspension system.
关于机械类的工作英语作文
关于机械类的工作英语作文Working in the field of mechanical engineering can be both challenging and rewarding. It requires a combination of technical skills, problem-solving abilities, and creativity. Every day, mechanical engineers are faced with new problems to solve and innovative solutions to develop.In this field, attention to detail is crucial. Whether it's designing a new machine or troubleshooting an existing one, every component must be carefully considered. From the smallest bolt to the largest gear, each part plays a vital role in the overall functionality of the machine.Communication is also an essential aspect of mechanical engineering. Engineers must be able to effectively communicate their ideas and designs to colleagues and clients. This involves not only explaining technical concepts but also listening to feedback and incorporating suggestions into the design process.One of the most exciting aspects of working in mechanical engineering is the opportunity to work oncutting-edge technology. Whether it's developing autonomous vehicles or designing renewable energy systems, mechanical engineers are at the forefront of innovation. They have the chance to shape the future and make a positive impact on the world.However, the field of mechanical engineering is not without its challenges. Engineers often face tight deadlines and high-pressure situations. They must be able to think quickly and adapt to changing circumstances. This requires a combination of technical knowledge and problem-solving skills.Despite the challenges, the field of mechanical engineering offers a wide range of career opportunities. Mechanical engineers can work in a variety of industries, including automotive, aerospace, and manufacturing. They can also choose to specialize in areas such as robotics, HVAC systems, or renewable energy.In conclusion, working in the field of mechanical engineering is both challenging and rewarding. It requires a combination of technical skills, problem-solving abilities, and creativity. Mechanical engineers have the opportunity to work on cutting-edge technology and make a positive impact on the world. Despite the challenges, the field offers a wide range of career opportunities.。
机械制造专业英语文章
机械制造专业英语文章篇一:机械专业英语文章中英文对照Types of Materials材料的类型Materials may be grouped in several ways. Scientists often classify materials by their state: solid, liquid, or gas. They also separate them into organic (once living) and inorganic (never living) materials.材料可以按多种方法分类.科学家常根据状态将材料分为:固体.液体或气体.他们也把材料分为有机材料(曾经有生命的)和无机材料(从未有生命的).For industrial purposes, materials are divided into engineering materials or nonengineering materials. Engineering materials are those used in manufacture and become parts of products.就工业效用而言,材料被分为工程材料和非工程材料.那些用于加工制造并成为产品组成部分的就是工程材料.Nonengineering materials are the chemicals, fuels, lubricants, and other materials used in the manufacturing process, which do not become part of the product.非工程材料则是化学品.燃料.润滑剂以及其它用于加工制造过程但不成为产品组成部分的材料.Engineering materials may be further subdivided into: ①Metal ②Ceramics ③Composite ④Polymers, etc.工程材料还能进一步细分为:①金属材料②陶瓷材料③复合材料④聚合材料,等等.Metals and Metal Alloys金属和金属合金Metals are elements that generally have good electrical and thermal conductivity. Many metals have high strength, high stiffness, and have good ductility.金属就是通常具有良好导电性和导热性的元素.许多金属具有高强度.高硬度以及良好的延展性.Some metals, such as iron, cobalt and nickel, are magnetic. At low temperatures, some metals and intermetallic compounds become superconductors.某些金属能被磁化,例如铁.钴和镍.在极低的温度下,某些金属和金属化合物能转变成超导体.What is the difference between an alloy and a pure metal? Pure metals are elements which come from a particular area of the periodic table. E_amples of pure metals include copper in electrical wires and aluminum in cooking foil and beverage cans.合金与纯金属的区别是什么?纯金属是在元素周期表中占据特定位置的元素.例如电线中的铜和制造烹饪箔及饮料罐的铝.Alloys contain more than one metallic element. Their properties can be changed by changing the elements present in the alloy. E_amples of metal alloys include stainless steel which is an alloy of iron, nickel, and chromium; and gold jewelry which usually contains an alloy of gold and nickel.合金包含不止一种金属元素.合金的性质能通过改变其中存在的元素而改变.金属合金的例子有:不锈钢是一种铁.镍.铬的合金,以及金饰品通常含有金镍合金.Why are metals and alloys used? Many metals and alloys have high densities and are used in applications which require a high mass-to-volume ratio.为什么要使用金属和合金?许多金属和合金具有高密度,因此被用在需要较高质量体积比的场合.Some metal alloys, such as those based on aluminum, have low densities and are used in aerospace applications for fuel economy. Many alloys also have high fracture toughness, which means they can withstand impact andare durable.某些金属合金,例如铝基合金,其密度低,可用于航空航天以节约燃料.许多合金还具有高断裂韧性,这意味着它们能经得起冲击并且是耐用的What are some important properties of metals?Density is defined as a material’s mass divided by its volume. Most metals have relatively high densities, especially compared to polymers.金属有哪些重要特性?密度定义为材料的质量与其体积之比.大多数金属密度相对较高,尤其是和聚合物相比较而言.Materials with high densities often contain atoms with high atomic numbers, such as gold or lead. However, some metals such as aluminum or magnesium have low densities, and are used in applications that require other metallic properties but also require low weight.高密度材料通常由较大原子序数原子构成,例如金和铅.然而,诸如铝和镁之类的一些金属则具有低密度,并被用于既需要金属特性又要求重量轻的场合.Fracture toughness can be described as a material’s ability to avoid fracture, especially when a flaw is introduced. Metals can generally contain nicks and dents without weakening very much, and are impact resistant. A football player counts on this when he trusts that his facemask won’t shatter.断裂韧性可以描述为材料防止断裂特别是出现缺陷时不断裂的能力.金属一般能在有缺口和凹痕的情况下不显著削弱,并且能抵抗冲击.橄榄球运动员据此相信他的面罩不会裂成碎片.Plastic deformation is the ability of bend or deform before breaking. As engineers, we usually design materials so that they don’t deform under normal conditions. You don’t want your car to lean to the east after a strong west wind.塑性变形就是在断裂前弯曲或变形的能力.作为工程师,设计时通常要使材料在正常条件下不变形.没有人愿意一阵强烈的西风过后自己的汽车向东倾斜.However, sometimes we can take advantage of plastic deformation. The crumple zones in a car absorb energy by undergoing plastic deformation before they break.然而,有时我们也能利用塑性变形.汽车上压皱的区域在它们断裂前通过经历塑性变形来吸收能量.The atomic bonding of metals also affects their properties. In metals, the outer valence electrons are shared among all atoms, and are free to travel everywhere. Since electrons conduct heat and electricity, metals make good cooking pans and electrical wires.金属的原子连结对它们的特性也有影响.在金属内部,原子的外层阶电子由所有原子共享并能到处自由移动.由于电子能导热和导电,所以用金属可以制造好的烹饪锅和电线.It is impossible to see through metals, since these valence electrons absorb any photons of light which reach the metal. No photons pass through.因为这些阶电子吸收到达金属的光子,所以透过金属不可能看得见.没有光子篇二:机械专业英语作文1Mechanical engineeringEngineering Science in life are widely used, especially in mechanical engineering in the application of life is almost throughout life in all its aspects, to automobiles, aircraft, small electric fans, umbrella, all of these and related machinery. The project includes many subjects, but the mechanical engineering is one of the most important subjects, not only because of our life and it is closely related to, but with the progress of the times, people have to rely on mechanical engineering products, in automation today, machine instead of many this is the part of the human labor, improve the efficiency and save time.As a result of mechanical engineering in every aspect of life, therefore, as an engineer, be faced with a great many challenges, inaddition to a solid with knowledge, but also keep pace with the times, familiar with the machinery and related software, can be very good use of software, and as a an engineer, we should try our best to design and produce and closely related to the life of the machine, and can in life play a real role, also have only such, we address and remission now social needs, therefore, the mechanical engineering in the future social development, will play the important role, especially China s case, the industry also is not very developed, machinery can be greater development space.Before the industrial revolution, machinery is mostly wood structure, wood made by hand by. The development of social economy, the demand for mechanical products. The bulk of the production increasing and precision processing technology progress, promote the mass production method ( interchangeability of parts production, professional division of labor and cooperation, water processing lines and assembly lines ) formation. Study of mechanical products in the manufacturing process, especially when used in the pollution of the environment and natural resources e_cessive consumption problems and their treatment measures. This is a modern mechanical engineering is an especially important task to grow with each passing day, and its importance.Application of mechanical products. This includes selection, ordering, acceptance, installation, adjustment, operation, maintenance, repair and transformation of the industrial use of machinery and complete sets of machinery and equipment, to ensure that the mechanical products in the long-term use of reliability and economy. As a student, we are now the most important to learn professional knowledge, only in this way, can we later life and learning, to do its part.机械工程工程科学在生活中应用广泛,特别是机械工程在生活中的应用几乎就是遍布了生活中的各个方面,大到汽车.飞机,小到电风扇.雨伞,这些都和机械有关.工程包括很多科目,但是机械工程是最重要的科目之一,不仅是因为它和我们的生活关系密切,而是随着时代的进步,人们已经依赖上机械工程制造出来的产品,而在自动化的今天,机器代替了许多本该是人类该做的部分劳动,提高了效率和节约了时间.由于机械工程遍布了生活的每一个方面,因此,做为一个工程师,要面临很大且很多的挑战,除了要具备扎实的装也知识外,还要与时俱进,熟悉和机械有关的软件,并要能很好的运用软件,而作为的一个工程师,我们要尽量设计和制造出和生活密切相关的机器,并能够在生活中起到真正的作用,也只有这样,我们解决和缓解现在社会上的需要,因此,机械工程在今后的社会的发展中,还是会起这重要的作用,特别是我国的这样的情况,工业还不是很发达的情况下,机械可发展的空间更大.工业革命以前,机械大都是木结构的,由木工用手工制成.社会经济的发展,对机械产品的需求猛增.生产批量的增大和精密加工技术的进展,促进了大量生产方法（零件互换性生产.专业分工和协作.流水加工线和流水装配线等）的形成.研究机械产品在制造过程中,尤其是在使用中所产生的环境污染和自然资源过度耗费方面的问题及其处理措施.这是现代机械工程的一项特别重要的任务,而且其重要性与日俱增.机械产品的应用.这方面包括选择.订购.验收.安装.调整.操作.维护.修理和改造各产业所使用的机械和成套机械装备,以保证机械产品在长期使用中的可靠性和经济性.做为学生,我们现在最重要的学好专业知识,只有这样,我们才能以后是生活和学习中,才能尽自己的一份力量.篇三:机械类专业英语课文参考翻译_pdf第一课该○翻译整理于网络,It is known that metals are very important in our life. Metals have the greatest importance for industry. All machines and other engineering[7endVi5niEriN] constructions have metal[5metl] parts; some of them consistonly of metal parts.众所周知,金属在我们的生活中是非常重要的,金属对于工业而言是有巨大的重要性,所有机器和其他工程构造都有金属零部件,其中一些还只能由金属组成.There are two large groups of metals:1) Simple metal- more or less pure chemical elements[5elimEnt]2) Alloys[5AlCi]- materials consisting of a simple metal combined with some other elements.有两大类金属:（1）纯金属——或多或少的金属元素（2）合金——组成纯金属的原料结合其他元素.About two thirds of all elements found in the earth are metals, but not all metals may be used in industry. Those metals which are used in industry are called engineering metals. The most important engineering metal is iron[5aiEn], which in the form of alloys with carbon[5kB:bEn] and other elements, finds greater use than any other metal. Metals consisting of iron combined with some other elements are known as ferrous[5ferEs] metals; all the other metals are called nonferrous[5nCn5ferEs] metals. The most importantnonferrous metal are copper[5kCpE], aluminum[E5lju:minEm], lead[li:d], zinc[ziNk], tin[tin], but all these metals are used much less than ferrous metals, because the ferrous metals are much cheaper.第 _._._._. 在地球上发现的所有元素中,大约三分之二是金属元素,但是并不是所有的金属都能够用于工业上.那些金属—我们用于工业上的金属—被称为工程金属,最重要的工程金属那就是铁,铁跟碳和其他元素结合形成合金的那些金属比其他金属发现有更大用途.铁与别的其他某些元素相结合而组成的金属称为黑色金属,此外所有其他金属都称为有色金属,最重要的有色金属是---铜,铝.铅.锌.锡.但是使 _课的翻译暂时没有. 用这些有色金属比使用黑色金属要少的多,因为黑色金属便宜得多.Engineering metals are used in industry in the form of alloys because the properties[5prCpEti] of alloys are much better than the properties of pure[pjuE] metals. Only aluminum may be largely used in the form of simple metal. Metals have such a great importance because of their useful properties or their strength, hardness, 翻译标准.请放心使 and their plasticity[plAs5tisiti].因为合金的特性比纯金属的好,所以工程金属以合金的形式用于工业,只有铝以纯金属的形式被广泛应用.金属因为具有强度.硬度和可塑性而发挥着特别重要的作用. 用.Different metals are produced in different ways, but almost all the metal are found in the forms of metal ore[C:(r)] (iron ore, copper ore, etc[et cetra].)以不同的方法生产不同的合金但是几乎所有的金属都是以金属矿的形式（铁矿.铜矿）被发现的.The ore is a mineral[5minErEl] consistence of a metal combined with some impurities[im5pjuEriti]. Inorder to produce a metal from some metal ore, we must separate these impurities from the metal that is done by metallurgy[me5tAlEdVi].矿石是一种由金属与某些杂质相混合而组成的矿物质,为了用金属矿石来生产出一种金属,我们必须把杂质从金属矿中分离出去,那就要靠冶炼来实现. Te_t:12. Plastics and Other MaterialsTe_t:Plastics[5plAstik, plB:stik] have specific properties which may makeik] acids[5AsId], such as sulphuric[sQl5fjuErik] acid and hydrochloric[7haidrEu5klC:rik] acid. Plastics tend to be resistant to these acids, but can have dissolved or deformed by solvent[5sClvEnt], suchas carbon tetrachloride[7tetrE5klC:raid], which have the same carbon base as the plastics. Color must be applied to the surface of metals, whereas it can be mi_ed in with plastics. Metals are more rigid[5ridVid] than most plastics while plastics are very light, with a specific[spi5sifik] gravity normally between 0.9 and 1.8. Most plastics do not readily[5redili] conduct[5kCndQkt] heat or electricity[Ilek5trIsItI]. Plastics soften slowly and can easily be shaped[Feip] when they are soft.塑料具有特殊的性能.对于某种用途而言,这些性能使得塑料比传统材料更为可取.例如,跟金属相比较,塑料既有优点也有缺点.金属易受到无机酸的腐蚀,如硫酸和盐酸,塑料能抵抗这些酸的腐蚀,但可被溶剂所洛解或引起变形,例如溶剂四氯化碳与塑料具有同样的碳基.颜色必定只能涂到金属的表面.而它可以跟塑料混合为一体.金属比大多数塑料刚性要好,而塑料则非常之轻,通常塑料密度在0. 9-1. 8之间.大多数塑料不易传热导电.塑料能缓慢软化,而当其还是在软的状态时,能容易成形.It is their plasticity[plAs5tisiti] at certain temperatures[5temprItFE(r)] which gives plastics their main advantages over many other materials. It permits the large-scale production of molded[mEuld] articles, such as containers, at an economic unit cost, where other materials require laborious[lE5bC:riEs] and often costly processes involving cutting, shaping, machining, assembly[E5sembli] and decoration.在某一温度下塑料是处于塑性状态的,这就使塑料具备超过许多其他材料的主要优点.它容许大量生产单位成本低廉的模制式器件,例如,各种容器.于此,若用其他材料则需要大量劳力和往往需要很费钱的加工工艺,比如,切割.成形.加工.装配和装饰.Plastics not only replace other materials. Their properties can be e_ploited[iks5plCit] for entirely[In5taIElI] new applications. For e_ample, plastics heart valves[vAlv] and other human spare parts have make possible many recent developments in surgery[5sE:dVEri].塑料不仅可以代替其他材料,而且它的特性能被开拓应用于全新领域,比如:随着最近外科手术的发展可能做成塑料的心脏瓣膜和其他人类的器官.There is no single plastics material which is suitable for all applications. It is important that the most suitable plastics should be chosen, and if necessary adapted[E5dApt], for each particular requirement. It is also important that the properties of the plastics chosen should be e_ploited to the best advantage.没有一种纯塑料材料适用于各个领域,如果有必要改进,对于每个有特殊要求的来说选择最合适的塑料是最重要的,被选择的塑料材料的特性被开拓得到更好的应用也是很重要的.A plastics article may need to differ in design and appearance from a similar article made from another material such as metal or wood. This is due[ ] not only to the properties of plastics but also to thetechniques[tek5ni:k] employed in fabricating[5fAbrikeit] plastics. These techniques include injection[in5dVekFEn] molding[5mEuldiN], blow molding, compression molding, e_trusion[eks5tru:VEn] and vacuum[5vAkjuEm] forming.塑料器件可能需要用其他材料比如:与金属或木材制作的类似的器件从设计和外观上加以区别,这不仅是由于塑料性能不同的原因,也是由于制造塑料产品所用的技术不同所致,这些技术包括:注塑.模制.吹塑模制.压模.挤压和真空成型等.23. Casting and Die-Casting AlloysTe_t:Casting[5kB:stiN] is one of the oldest metal working techniques known to man. Our country made metal castings as early as _ B.C., and the process used then is not much different in principle[5prinsEpl] from the one used today.铸造是入类所掌握的最古老的金属加工技术之一.我国早在公元前 _年就已把金属制成铸件,而所使用的工艺从原理上和今天的工艺没有多大的区别.Foundry[5faundri]processesconsistof makingmolds,preparingandmelting[melt]themetal, pouring[pC:, pCE] the metal into the molds, and cleaning the castings. The product of the foundry is a casting, which may vary from a fraction[5frAkFEn] of a kilogram to several hundred tons. It may also vary in composition[kCmpE5ziFEn] as practically all metals and alloys can be cast.铸造工艺由制模.备料和金属熔炼,金属液浇注入模和铸件清砂等.铸造的产品是铸件,铸件可能从零点几公斤到几百吨范围变化.实际上所有金属在成分上也是变化的,而合金也可以铸造.The metals most frequently cast are iron, steel, aluminum and so on. Of these, iron, because of its low melting point, low price and ease of control, is outstanding for its suitability[9sjU:tE`bIlEtI] for casting and is used far more than all the others.最常铸造的金属是铸铁.钢.铝等等.这些金属中,铸铁,由于其低熔点,低价格和易控制,因而其铸造适应性是最突出的,而且使用也远比所有其他金属多.Castingisawidelyusedmethodofproducingmetalproducts,particularlythosew hichareintricate[5intrikit]. Since molten materials will readily take the shape of the container into which they are poured, it is nearly as easy to cast fairly comple_ shapes as to produce simple forms.由于熔融的物料能容易取得被浇注进去的容器（模型）的形状,因此,几乎像生产简单形状铸件那样颇为容易地铸造出复杂形状的铸件.The place where the metals are cast is called a foundry. The most important of cast metals is cast iron which is made from pig iron by remelting it in a special melting furnace[5fE:nis] called a cupola[5kju:pElE].铸造金属的地方叫做铸造车间.最重要的铸造金属是铸铁,铸铁是用生铁在一个特殊的熔炉—叫冲天炉的炉子中重新熔炼而制造出来的.From the cupola, the cast iron flows into ladles[5leidl] of different size, and from these ladles it is poured into the molds.从冲天炉中出来的铁水流入到不同规格的铁水包中,并从这些铁水包中被浇注到模型中.The molds may be of two kinds: sand molds and metal molds. A metal mold consists of two hollow parts which should be joined for pouring the metal into it. The inside of this mold is covered with carbon or graphite[5 Afait] so that the metal could not stick[stik] to the wall of the form. When the metal has solidlocks of steel produced by pouring the metal into these molds are called ingots and the process is called ingot casting.模型有两种类型:砂模和金属模.金属模是由两个中空的部件组成,它们应被联结在一起以便将金属液浇入模箱中.这模腔的内侧是要涂以碳粉或石墨,因此金属不玫于粘贴到型腔壁上口当金属液凝固后,这中空的型箱部件被打开并取出铸件.也有一种特殊模型,在该模型中可以铸造大型钢块.这些模型通常用铸铁米制造,并被称为锭模.而浇注金属液到这些模子中生产出的钢块被称为钢锭.该工艺过程叫锭铸.A relatively[5relEtIvlI] wide range of nonferrous alloys can be die-cast. The principal base metals used, in order to commercial importance, are zinc, aluminum, copper, magnesium[mA ni:zjEm], lead, and tin. The alloys may be further classified as low-temperature alloys and high-temperature alloys; those having a casting 3temperature below 538C, such as zinc, tin, and lead, are in the low-temperature class. The low-temperature alloys have the advantages of lower cost of production and lower die-maintenance[5meintinEns] costs. As the casting temperature increases, alloy and other special steels in the best treated condition are required to resist the erosion[i5rEuVEn] and heat checking[5tFekiN] of die surface. The destructive[dis5trQktiv] effect of high temperaturesonthedies hasbeentheprincipalfactorinretarding[ri5tB:d] thedevelopmentof high-temperature die castings.相当大量的有色金属合金可以进行模铸}h 用的主要而基本的金属,按其在工业上应用的重要性的顺序是锌.铝.铜.锰.铅和锡.这些合金可以进一步进行分类为低温类合金和高温类合金.铸造温度低于538℃的那些合金,就像锌.锡和铅,是属于低温类合金.低温类合金具有低生产成本和低的模具维修费用等优点.当铸造温度上升时,需要最佳条件下处理过的合金钢和其他特种钢来抵抗腐蚀及防止模具表面的热裂纹.高温在模具上的损坏作用已经成为阻碍.延缓高温模铸发展的主is more pronounced[pr5naunst] with some alloys than with others. Aluminum, in particular, has a destructive action on ferrous metals and, for this reason, is seldom melted in the machine, whereas the copper-basealloys are never melted in the machine.控制选择合金的另外一个因素就是熔融的金属在相关的机器零件上和模具上的腐蚀或溶解作用.这种作用随着温度的升高而增加,甚至某些合金比另一些合金更为明显.特别是 .铝对黑色金属有一种破坏作用,为此.铝几乎不熔混于机器零件中,而铜基合金是决不能熔混于机器构件中的.44. ForgingTe_t:Press forging[5fC:dViN] employs a slow squeezing[skwi:z] action in deforming[di:5fC:m] the plastic metal, as contrasted with the rapid-impact[5impAkt] blows of a hammer. The squeezing action is carried completely to the center of the part being pressed, thoroughly working the entire section[5sekFEn]. These presses are the vertical[5vE:tikEl] type and may be either mechanically[mi5kAnikEli] or hydraulically[hai5drC:lik] operated. The mechanical presses, which are faster operating and most commonly used, range in capacity[kE5pAsiti] from 5_ to 1_0 tons.与锤锻的快速冲击不同,压力机锻造是用缓慢的挤压作用使塑性金属变形.这挤压作用完全被施加到正在被压锻的零件中心位置上,直至彻底使整个工件得到加工.这些压力机都是立式的,可能是机械操作也可能是液压操作的.机械操作压力机,操作速度比较快,使用最普遍,锻造能力从 5_吨到1__吨范围.For small press forgings, closed impression dies are used and only one stoke of the ram[rAm] is normally required to perform[pE5fC:m] the forging operation. The ma_imum[5mAksimEm] pressure is built up at the endof the stroke which forces the metal into shape. Dies may be mounted[maunt] as separate units, or all the cavities may be put into single block. Forsmall forgings, individual[7indi5vidjuEl] die unites are more convenient. There is some difference in the design of dies for different metals; copper-alloy forgings can be made withless draft[drB:ft] than steel,consequently more complicated[5kCmplikeitid]shapes can be produced. These alloys flow well in the die and are rapidly e_truded 对于小型压力锻使用闭式锻模.通常要求锻锤仅一个冲程就完成锻造工艺.在冲程终端产生最大压力,该冲击压力迫使金属成形.模具可由各白独立的单元装配而成,即把所有个别模腔都放到一起,组成整体.对于小型锻件使用分模装置更为方便.对于不同的金属在模具设计上有些区别 .铜合金锻件比钢件用较小的拔模斜度,因此可生产更加复杂形状的锻件.这些合金在该种模具中流动性好,而且能快速挤压成形.In the forging press, a greater proportion of the total work put into the machine is transmitted[trAnz5mit] to the metal than in a drop hammer press. Much of the impact of the drop hammer is absorbed by the machine and foundation. Press reduction of the metal is faster, and the cost of operation is consequently lower. Most press forgings are symmetrical[si5metrikEl] in shape, having surfaces which are quite smooth, and provide a closer tolerance[5tClErEns] than is obtained by a drop hammer. However, many parts of irregular[i5re…ulE] and complicated shapes can be forged more economically by drop forging. Forging press is often used for sizing operations on parts made by other forging processes.锻压机比落锤锻,输入到机器里的总能量中有更大部分的能量被传输到金属坯料上.落锤锻的冲击能量被机器和基础吸收得较多(比起压力机来〕.金属上的压力衰减较快,因此生产成本比较低.大多数压力锻锻件形状.产生的表面都是对称的,而且表面非常光滑,并比落锤锻件的公差尺寸更加精确.然而落锤锻造可以锻制形状复杂而不规则的锻件,因而较为经济.锻压机常常用来为其他锻造工艺所生产的锻件进行整形和校正加工用.In drop forging, a piece of metal, roughly[5rQflI] or appro_imately of the desired[di5zaiE] shape, is placed between die faces having the e_act form of the finished piece, and forced to take thin form by drawing the dies together. Large ingots are now almost always forged with hydraulic presses instead of with steam hammers, sinc。
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What is Hydraulic?A complete hydraulic system consists of five parts, namely, power components, the implementation of components, control components, no parts and hydraulic oil. The role of dynamic components of the original motive fluid into mechanical energy to the pressure that the hydraulic system of pumps, it is to power the entire hydraulic system. The structure of the form of hydraulic pump gears are generally pump, vane pump and piston pump. Implementation of components (such as hydraulic cylinders and hydraulic motors) which is the pressure of the liquid can be converted to mechanical energy to drive the load for a straight line reciprocating movement or rotational movement. Control components (that is, the various hydraulic valves) in the hydraulic system to control and regulate the pressure of liquid, flow rate and direction. According to the different control functions, hydraulic valves can be divided into the village of force control valve, flow control valves and directional control valve. Pressure control valves are divided into benefits flow valve (safety valve), pressure relief valve, sequence valve, pressure relays, etc.; flow control valves including throttle, adjusting the valves, flow diversion valve sets, etc.; directional control valve includes a one-way valve , one-way fluid control valve, shuttle valve, valve and so on. Under the control of different ways, can be divided into the hydraulic valve control switch valve, control valve and set the value of the ratio control valve. Auxiliary components, including fuel tanks, oil filters, tubing and pipe joints, seals, pressure gauge, oil level, such as oil dollars. Hydraulic oil in the hydraulic system is the work of the energy transfer medium, there are a variety of mineral oil, emulsion oil hydraulic molding Hop categories.Hydraulic principleIt consists of two cylinders of different sizes and composition of fluid in the fluid full of water or oil. Water is called "hydraulic press"; the said oil-filled "hydraulic machine." Each of the two liquid a sliding piston, if the increase in the small piston on the pressure of a certain value, according to Pascal's law, small piston to the pressure of the pressure through the liquid passed to the large piston, piston top will go a long way to go. Based cross-sectional area of the small piston is S1, plus a small piston in the downward pressure on the F1. Thus, a small piston on the liquid pressure to P = F1/SI,Can be the same size in all directions to the transmission of liquid. "By the large piston is also equivalent to the inevitable pressure P. If the large piston is the cross-sectional area S2, the pressure P on the piston in the upward pressure generated F2 = PxS2 Cross-sectional area is a small multiple of the piston cross-sectional area. From the type known to add in a small piston of a smaller force, the piston will be in great force, for which the hydraulic machine used to suppress plywood, oil, extract heavy objects, such as forging steel.History of the development of hydraulicAnd air pressure drive hydraulic fluid as the transmission is made according to the 17th century, Pascal's principle of hydrostatic pressure to drive the development of an emerging technology, the United Kingdom in 1795 Joseph (Joseph Braman ,1749-1814), in London water as a medium to form hydraulic press used in industry, the birth of the world's first hydraulic press. Media work in 1905 will be replaced by oil-water and further improved.World War I (1914-1918) after the extensive application of hydraulic transmission, especially after 1920, more rapid development. Hydraulic components in the late 19th century about the early 20th century, 20 years, only started to enter the formal phase of industrial production. 1925 Vickers (F. Vikers) the invention of the pressure balanced vane pump, hydraulic components for the modern industrial or hydraulic transmission of the gradual establishment of the foundation. The early 20th century Constantine (G • Constantimsco) fluctuations of the energy carried out by passing theoretical and practical research; in 1910 on the hydraulic transmission (hydraulic coupling, hydraulic torque converter, etc.) contributions, so that these two areas of development.The Second World War (1941-1945) period, in the United States 30% of machine tool applications in the hydraulic transmission. It should be noted that the development of hydraulic transmission in Japan than Europe and the United States and other countries for nearly 20 years later. Before and after in 1955, the rapid development of Japan's hydraulic drive, set up in 1956, "Hydraulic Industry." Nearly 20 to 30 years, the development of Japan's fast hydraulic transmission, a world leader. Hydraulic transmission There are many outstanding advantages, it is widely used, such as general workers. Plastic processing industry, machinery, pressure machinery, machine tools, etc.; operating machinery engineering machinery, construction machinery, agricultural machinery, automobiles, etc.; iron and steel industry metallurgical machinery, lifting equipment, such as roller adjustment device; civil water projects with flood control the dam gates and devices, bed lifts installations, bridges and other manipulation of institutions; speed turbine power plant installations, nuclear power plants, etc.; ship deck crane (winch), the bow doors, bulkhead valves, such as the stern thruster ; special antenna technology giant with control devices, measurement buoys, movements such as rotating stage;military-industrial control devices used in artillery, ship anti-rolling devices, aircraft simulation, aircraft retractable landing gear and rudder control devices and other devices.。