chap4_lect_SemII_080511_EE.pptx - CHAPTER 4 INTRODUCTION TO WEAR WEAR MECHANISMS 1 4.1 Introduction \u2022 Wear is the surface damage or the removal of the

chap4_lect_SemII_080511_EE.pptx - CHAPTER 4 INTRODUCTION TO...

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CHAPTER 4 INTRODUCTION TO WEAR & WEAR MECHANISMS 1
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4.1 Introduction Wear is the surface damage or the removal of the material from the surface of a solid body as a result of mechanical action of the counter body. /sliding, rolling or impact motion/. Wear may combine effects of various physical and chemical processes proceeding during the friction between two counteracting materials: micro-cutting micro-ploughing plastic deformation cracking fracture welding and melting 3
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. 4
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There are five different types of wear (wear mechanisms): adhesive, abrasive, fatigue, corrosive and erosive wear . In many cases, the combinations of the adhesive, corrosive and abrasive forms of wear occur : two-thirds of all wear encountered in industrial situations occurs because of adhesive-and abrasive wear mechanisms. Wear by all mechanisms except by fatigue mechanism , occurs by gradual removal of material. Objective : to understand the wear mechanisms and control methods . 5
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4.2 Wear mechanisms Wear occurs by mechanical action and is generally accelerated by frictional heating (or thermal means). Wear includes five principal , quite distinct phenomena that have only one thing in common: the removal of solid material from rubbing surfaces. Types of wear are: 1. Adhesive wear 2. Abrasive wear 3. Fatigue wear 4. Corrosive wear 5. Erosive wear 6
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4.2.1 Adhesive wear Adhesive wear occurs when two normally flat bodies are in sliding contact . The load applied is so high that adhesion (or bonding) and deformation occurs at the asperity contacts at the interface, and these contacts are sheared by sliding. The motion of the rubbing counter bodies result in rupture of the micro-joints. Thus some of the material is transferred by its counter body. 7
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. metal 8
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  • Fall '19
  • Msc. Amar Yemim

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