• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Metallography. The objective of our experiment is to learn specimen preparation techniques in metallography and study the microstructures of typical engineering alloys. The objective of the lab report is to explain the techniques that were learned and u

Extracts from this document...


METALLOGRAPHY LAB #3 APRIL 28, 2005 METALLURGY 331 OBJECTIVE This laboratory experiment and report have 2 separate objectives: The objective of our experiment is to learn specimen preparation techniques in metallography and study the microstructures of typical engineering alloys. The objective of the lab report is to explain the techniques that were learned and use them to help identify the specific alloy that was provided for the experiment. INTRODUCTION The term metallography has been in use since the 1700's, however at that time it was defined as the description of metals and their properties. It was not used in its modern sense, the process of preparing a metallic sample and observing or recording its microstructure, until 1892. Since then, there have been constant advancements in technology, which have provided a far superior procedure which is in use today. The metallographic preparation process can be subdivided into 5 categories: - sectioning - mounting - grinding - polishing - etching Sectioning can be defined as the removal of a conveniently sized, representative specimen from a larger sample. There are different methods of sectioning which include fracturing, shearing, sawing, abrasive cutting, and electric discharge machining. For our experiment we used an abrasive cutting machine. Abrasive cutting is the most widely used method of sectioning and there are 2 types of abrasive cutters, consumable and non-consumable. Consumable abrasive cutters are beneficial because it is fast, accurate, economical and there are an almost innumerable number of consumable wheels available which provide more control over the conditions required than do other methods of sectioning. ...read more.


In order to verify the type of metal that we were given for this experiment we not only had to perform the metallographic preparation process we also had to develop a selection process to match the microstructure of the unknown specimen with known metals. For the preparation process we employed the 5 steps: sectioning, mounting, grinding, polishing and etching. - For sectioning procedure we used the Buehler Metallurgical Cutting Apparatus which is a non-consumable abrasive cutting device. When the specimen is placed in the clamps make sure there is enough material exposed to cut a 1/4" section. This device uses coolant which can get messy at times, so it is recommended to use latex gloves while operating. - Once the specimen was properly sectioned it was mounted using Bakelite, a thermosetting resin. The resin was heated and placed under pressure in an automatic curing apparatus. - For the grinding procedure we used the Buehler Handimet Grinder. This circular grinder has 2 flat grinding surfaces with increasingly fine grit abrasives used to sand and buff metal surfaces. To properly grind the surface of the specimen, the following steps were followed: o Open water line located behind grinder. o Turn coolant on by turning coolant knob slightly counterclockwise. o Starting on the 240 grit surface, place the prepared specimen face down on the abrasive surface, and begin sliding specimen against abrasive in a forward and backward motion. ...read more.


They both have high amounts of pearlite, and the ferrite concentrations are rather evenly distributed throughout the sample. The main difference between the two is the size of their microstructure. I believe this may have occurred from two different magnifications being used. The magnification of the picture we captured was higher than of the one in the ASM Handbook. Because of these reasons, I do believe that these two metals are one in the same. Performing this experiment has helped me to understand how to apply the metallographic preparation process to help identify an unknown material. The results indicate that I may need a little more practice to increase my precision in this procedure, but I have a good understanding of the principles behind it. CONCLUSION The research that was performed in this experiment was beneficial to my overall understanding of the metallographic process and I realize that there is room for improvement in my execution of this process. The next time that I perform this process I will be mindful of the angle at which the specimen is being held during the grinding, sanding, and polishing processes, so as to provide a flat surface. By doing this it should eliminate the fuzzy appearance of most of the material in the image. Additionally, once I complete the etching process I will try to eliminate the delay between removal of the specimen from the etching solution and taking the picture under the microscope. This wasted time is the reason why corrosion began to propagate across the specimen. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Resistant Materials section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Resistant Materials essays

  1. Evaluation I created jewelry rings with two different methods stamping and etching.

    Small mistakes would develop and cause problems. I made quite a few changes to the original plan. (1) I changed the sheet metal from copper to brass. (2) I was originally going to have Russian dolls in a descending order of sizes (Large to small).


    Thus due to this my initial assumption is that sample F will be stronger than sample A, but A will be more ductile, due to F containing more carbon. 6 Looking at the results graph, sample A, you can see where the linear region ends and where the plastic deformation begins.

  1. Create and sell an accessory collection (starting a small business)

    parties or places where there are lots of people they are able to promote my collection, and that creates very good results because sometimes I get a phone call asking me to do a very important request of accessories or maybe people ask who was the one that did the

  2. Recycling report

    Turning recycled drink can into a new one take as little as six weeks. Cardboard is bulked and sent to mills where it is soaked, pulped, pressed out into sheets and dried, ready to be used again. It can be made into new boxes and packaging or it can be used for animal bedding or compost.


    The shrinkage factor used in designing the mold must take the potential for change in post molded dimensional into account. Although moisture causes problems in working with Nylons, it does contribute to: better dye ability, toughness, softness and greater flexibility in Nylon parts. Another dominant feature of Nylons is crystallinity.

  2. Technical Report The Construction of Alloy Wheels

    This report will focus mainly on the casting processes used. Casting Processes The most common process of constructing alloy wheels is One-Piece Casting, there are a number of methods to do this, and the most basic is Die Casting, this process is used world wide throughout the casting industry and is not exclusive to alloy wheels.

  1. TASK: Turning a Mild Steel Bar.We were each given a mild steel bar to ...

    Spot welding is the most commonly used form of resistance welding. Usually used on sheet metal and in applications having some type of overlapping joint design, resistance spot welds are made from electrodes on both sides of the joint. No filler metal is used.

  2. Investigate and evaluate the differences and similarities in the key features in planning the ...

    will appoint another Approved Contractor to carry out the work - again at no extra cost to the consumer. The current legislation controlling the installation and use of gas is the Gas Safety (Installation and Use) Regulations 1998 which came into force on 31 October 1998 and place duties mainly on installers and some gas suppliers.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work