MSE_250_Hardenability-Lab - Once completely cooled, the...

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MSE 250 Hardenability of Steel Objective : This purpose of this laboratory exercise is will be to demonstrate the hardenability of various steel with similar carbon content, using the Jominy end-quench test. Readings : Read CCT of Fe-C alloy in Ch. 10 and effect of alloying elements in Ch. 11 “Hardenability of Plain Carbon Steel” Pre-Lab. What are the compositions for 1045, 4140 and 4340 steel Procedure: Prior to lab, a cylindrical steel bar has been austenitized for at 920°C for at least 30 minutes. Remove the steel bar and loaded onto the Jominy fixture (see figure below). The end of steel bar is 0.5 inch above the water nozzle, quenched with continuous water flow for 0-12 minutes. Remove the sample from the fixture and immerse it in water to ensure safety.
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Unformatted text preview: Once completely cooled, the bolt and washer are to be removed. Clean-up the specimen to facilitate hardness testing. Hardness measurements are taken using the Rockwell C scale and as follows; starting at the quenched end, make 10 measurements for the first inch, and 5 measurements for the next inch and 3 measurements for the remainder of the bar. Each group will plot hardness vs. distance for the specimen, as well as to answer the following questions. Q1: Why does hardness change along the length of the bar? Q2: How would you expect this data to be different for alloy steel or for steel with lower carbon content? Why? Q3: Draw the expected microstructure along the length of the bar for your specimen, based on the hardness measurements....
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This document was uploaded on 10/28/2011 for the course MSE 250 at Michigan State University.

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