Preface

In the 21st century, material science is developing vigorously; new materials and new technologies emerge endlessly, which greatly promote the development of science and technology and national economy. It is very important for engineering students to have a proper understanding of the direction of modern materials development.
  Machinery is manufactured. Due to the different types of machinery and equipment in all walks of life, mechanical manufacturing involves a wide range of areas. Metallurgy, construction, water conservancy, machinery, electronics, information, transportation, agriculture and other industries need the support of manufacturing industry. Metallurgy industry needs smelting and rolling equipment; construction industry needs tower crane, excavator, bulldozer and other engineering machinery. Manufacturing industry has always occupied an important position in China. In the 1950s, the machinery industry was divided into eight sectors: general, nuclear, aviation, electronics, ordnance, shipbuilding, aerospace and agriculture. In the 21st century, the world is undergoing extremely extensive and profound changes, and the machinery manufacturing industry affected by it has also undergone earthshaking changes. However, no matter how the world changes, machinery manufacturing industry has always been the basic industry of the national economy, and its development directly affects the development of all sectors of the national economy.
  In the compilation of this book, we have consulted a large number of domestic and foreign teaching materials, treatises and other literature materials. Due to the limited space, they will not be listed one by one. Sincere thanks would be expressed to the authors of these literature. At the same time, due to the editor's limited level and ability, there are inevitable mistakes and omissions in the book. We sincerely hope that experts, scholars and readers can criticize and correct them, so as to further improve them in the future. 

前 言

进入 21 世纪，材料科学蓬勃发展，新材料、新技术层出不穷，极大地推动了科学技术和国民经济的发展。适当地了解现代材料的发展方向对于工科学生具有极其重要的意义。
       机械是制造出来的，由于各行各业的机械设备不同、种类繁多，因此机械制造
的涉及面非常广，冶金、建筑、水利、机械、电子、信息、运载和农业等各个行业都要有制造业的支持，冶金行业需要冶炼、轧制设备；建筑行业需要塔吊、挖掘机和推土机等工程机械。制造业在我国一直占据重要地位，在 20 世纪 50 年代，机械工业就分为通用、核能、航空、电子、兵器、船舶、航天和农业等八个部门。进入21 世纪，世界正在发生极其广泛和深刻的变化，随之牵动的机械制造业也发生了翻天覆地的变化。但是，不管世界如何变化，机械制造业一直是国民经济的基础产业，它的发展直接影响到国民经济各部门的发展。
      在本书的编写过程中，我们参阅了大量国内外教材和论著等文献资料，由于篇幅有限，恕不一一列出，在此对这些文献的作者一并表示诚挚的谢意。同时，由于编者水平和能力有限，书中难免存在错误与遗漏，我们诚恳地希望各位专家、学者和广大读者批评指正，以便今后进一步完善。