Mechanical Engineering > Lab Report > ME2151E full Lab Report (Metallography):Principles of Mechanical Engineering Materials Cooling Rate (All)

ME2151E full Lab Report (Metallography):Principles of Mechanical Engineering Materials Cooling Rate Effect Lab Report

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Table of Contents 1. Introduction.................................................................................................................2 2. Observations and Results.......................... .....................................................................3 3. Discussion and Analysis of Results..............................................................................6 4. Conclusion...................................................................................................................8 1. Introduction Metallography is defined as the visual study on the constitution and structure of materials. Two types: a. Macroscopic examinations b. Microscopic examinations 1.1 Objectives  To study the microstructural details and correlate with the ensuing mechanical properties of the material.  Further understanding on the heat treatment effect to an alloy.  To obtain experience in the metallographic preparation of metallic specimens.  To observe the various microstructures in a fusion welded steel. 1.2 Metallographic Preparation of the Specimens 1. Specimen Preparation - Identify the phase or phases present and the grain size of the material from your metallographic examination. Prepare two steel plates (0.5% C contain) and proceed with fusion welding process by adding filling to the joint gap 2. Mounting - For easy handling, mount the welded piece to the plastic mould with the surface to be examined is exposed on one side, plastic or resin added. 3. Rough Grinding - Rough grinding with coarse abrasive manually. 4. Fine Grinding -Fine grinding using semi-automated grinding machine with industrial grade diamond surface. 5 to 6N load were applied to hold the specimen during the grinding process. Water jet is supplied as a lubricant. Fine grinding will be carried out for 5 minutes and wash the specimens. 5. Polishing - Polishing against cloth is done by rotating wheels to get a mirror surface by rubbing the surfaces with Alumina solution which contain 5 micron sizes particles. Water droplets as a lubricant are supplied so that it can help in to drive the abrasive to the desired surface area. 5 minutes of polishing required. Specimens must be washed and dried before and after the process. 6. Etching - Etching will bring out the structure of polished surface. Etching is a chemically treatment to the surface with alkaline or acidic solution. The surface were attacked differentially generate contrast to be microstructural examination. The etched specimens should be washed under stream of running water and dried untouched by holding in air current. 2. Observations and Results 3. Discussion and Analysis of Results Welding Zone During Welding After Welding Unaffected Zone Liquid Transition Zone ϒ Grain Refinement Zone Fine ϒ Grain Growth Zone α + fine ϒ Fusion Zone α + P [Show More]

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