《lesson1-2.ppt》由会员分享，可在线阅读，更多相关《lesson1-2.ppt（15页珍藏版）》请在三一文库上搜索。
1、Review,Translate the following phrases: mechanical properties proper operation evaluation of the function and requirements in most applications,Answer the questions How to select the tool materials? Firstly, to be a careful study and evaluation of the function and requirements of the proposed tool.
2、Secondly, to be determined by the mechanical properties. Finally, to consider the material availability and economy. (2) How many kinds of materials used for tool? Three kinds: ferrous, nonferrous, nonmetallic materials. Ferrous: tool steel, alloy steel, carbon steel, and cast iron Nonferrous: alumi
3、num, magnesium, zinc, lead, bismuth, copper, and a variety of alloys,Nonmetallic materials are those materials such as woods, plastics, rubbers, epoxy resins, ceramics, and diamonds that do not have a metallic base. （非金属材料是那些不含金属基体的材料，例如木材、塑料、橡胶、环氧树脂、陶瓷和金刚石。）,To properly select a tool material,there
4、 are several physical and mechanical properties you should understand to determine (how the materials you select will affect the function and operation of the tool.) （为了适当的选择工具材料，我们应该掌握所选择的材料的一些物理性能和力学性能，以便确定所选材料对刀具的性能和操作有什么影响。）,Physical and mechanical properties are those characteristics of a mater
5、ial which control how the material will react under certain conditions. （材料的物理性能和力学性能是控制材料在特定情况下如何发生变化的性能。） Physical properties are those properties which are natural in the material and cannot be permanently altered without changing the material itself. （物理性能是材料固有的特性，不会随着材料本身的改变而改变。） These properti
6、es include: weight, color, thermal and electrical conductivity, rate of thermal expansion, and melting point. （这些物理性能包括：重量、颜色、热导率和电导率、受热膨胀率（热膨胀系数）和熔点。） The mechanical properties of a material are those properties which can be permanently altered by thermal or mechanical treatment. （材料的力学性能是能通过热加工和冷加
7、工发生永久变化的性能。）,These properties include strength, hardness, wear resistance, toughness, brittleness, plasticity, ductility, malleability, and modulus of elasticity. （力学性能包括强度、硬度、耐磨性、韧性、脆性、塑性、延展性、切削性能、弹性模量。）,From a use standpoint, tool steels are utilized in working and shaping basic materials such as
8、metals, plastics, and wood into desired forms. （从使用角度看，加工和成形金属、塑料和木材等时要用工具钢） From a composition standpoint, tool steels are carbon alloy steels which are capable of being hardened and tempered. （从组成成分的角度看，工具钢是碳素合金钢，能够进行淬火和回火处理。） Some desirable properties of tool steels are high wear resistance and h
9、ardness, good heat resistance, and sufficient strength to work the materials. （工具钢的一些所需要的性能用于加工原材料，如高耐磨性和高硬度、好的耐热性和足够的强度。） In some cases, dimensional stability may be very important. （某些情况下，材料的尺寸稳定性是很重要的。） Tool steels also must be economical to use and be capable of being formed or machined into the
10、 desired shape for the tool. （工具钢也一定要经济合理的使用，并能够成形或者加工成所需要的工具形状。）,Since the property requirements are so special, tool steels are usually melted in electric furnaces using careful metallurgical quality control. （由于性能需求是如此特殊，所以通常工具钢常在具有严格冶金质量控制的电炉中熔化。） A great effort is made to keep porosity, segrega
11、tion, impurities, and nonmetallic inclusions to as low a level as possible. （在冶炼的过程中，尽最大努力去消除气孔、偏析、夹杂以及非金属杂质。） Tool steels are subjected to careful macroscopic and microscopic inspections to ensure that they meet strict tool steel specifications. （工具钢要受到严格的宏观和微观检查，以确保它们满足真正的“工具钢”的要求。）,Although tool
12、steels are a relatively small percentage of total steel production, they have a strategic position in that they are used in the production of other steel products and engineering materials. （尽管工具钢在整个钢材产量中相对而言只占一小部分，但是由于工具钢在其他钢材产品和工程材料中的应用，使得工具钢占据着重要的位置。） Some applications of tool steels include dril
13、ls, deepdrawing dies, shear blades, punches, punches, extrusion dies, and cutting tools. （工具钢的一些应用场合包括钻孔、拉深模具、剪切刀片、冲床、冲孔、挤出模和切削刀具等。） For some applications, especially where extremely high-speed cutting is important, other tool materials such as sintered carbide products are a more economical alterna
14、tive to tool steels. （在一些应用中，尤其是在高速切削非常重要的条件下，其他的刀具料例如硬质合金（烧结碳化物产品）是比工具钢更经济的替代产品。） The exceptional tool performance of sintered carbides results from their very high hardness and high compressive strength. （硬质合金（烧结碳化物）的特殊的刀具性能是由它们的高硬度和高耐压强度决定的。） Other tool materials are being used more and more often industrially. （其他的刀具材料正在被越来越多的应用于工业中。）,