机电专业英语全书电子教案完整版教学设计.doc

机电专业英语教案 PAGE PAGE 6 模块1 Module 1 Foundation of Mechanical Technology 学习任务1 Task 1 Mechanical Engineering Teaching content Remarks Text 1.1.1. Drawing 1. Engineering drawing Typical drawings in machine manufacturing are classified as part drawings and assembly drawings. 在机械制造中比较典型的机械图样有两种：零件图和装配图。 Fig.1-1-1 Part drawings Fig.1-1-2 Assembly drawings 2. Representation of machine elements Mechanical drawings in national standards are restricted to those which specify the view, sectional view and broken sectional view to represent the structures and shapes. 国家《机械制图》标准规定采用视图、剖视图、断面图等各种方法来表达机件的结构和形状。 Basic views Sectional views Broken sectional views 1.1.2 Properties of Metals 1. Metals Metals are divided into two general groups: ferrous metals and nonferrous metals. The major types of ferrous metals are iron, carbon steels, alloy steels and tool steels. 金属材料分为两种基本类型：铁类金属和非铁金属。铁类金属主要有铸铁、碳钢、合金钢和工具钢。 The three primary types of cast iron are gray cast iron, white cast iron, and malleable iron. 铸铁主要分为三种：灰铸铁、白口铸铁和可锻铸铁。 The three principal types of carbon steel used in industry are low, medium, and high carbon steel. 工业上使用的碳钢主要有三种：低碳钢、中碳钢和高碳钢。 2. Properties of metals Strength is a property of metal that allows it to resist permanent change in shape when loads are applied. 强度是材料在载荷作用下抵抗塑性变形的能力。 Hardness is the ability of a metal to resist indentation or penetration. 硬度是材料抵抗压痕或划痕的能力。 Wear resistance is the ability of a metal to resist abrasion. 耐磨性是材料抵抗磨损的能力。 Toughness is the ability of a metal to resist, or absorb, sudden shocks of loads without breaking. 韧性是材料抵抗或吸收或冲击载荷而不发生破坏的能力。 Plasticity is the ability of a metal to be extensively deformed without fracture or rupture. 塑性是材料产生塑性变形而不被破坏的能力。 Brittleness is the property of a metal that causes it to fracture rather than deform when loads are applied. 脆性是指材料在载荷作用下不产生明显变形而直接发生破坏的特性。 1.1.3 Heat Treatment of Metals Fig.1-1-6 Heat treatment curve Purposes of annealing: rem