lab2.docx - Mideast Engineering and Testing INC Material...

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Mideast Engineering and Testing, INC. “Material properties is the key to success!” 501 Mercury Drive Champaign, Il 61822 February 22, 2018 Dr. John Popovics Popovics Manufacturing Co. 4200 Industrial Blvd. Morristown, NJ 07960 Dear Dr. Popovics, On behalf of Mideast Engineering and Testing, is our pleasure to send you these experimental results. Four different specimens, which made of 1045 normalized steel, cast iron, 6061-T6 aluminum and polymethylmethacrylate, were subjected to a compression test. Also, 6061-T6 aluminum and 4340 steel were subjected to hardness test using Rockwell B, Rockwell C, and Brinell separately. After hardness test performed by Brinell hardness tester, the diameter of indentation was measured by a readout microscope. All the dimensions were measured by a digital caliper, and all the data was recorded by a computer data acquisition system. For the specimens performed in the compression test, PMMA ruptured during the loading which has an ultimate compressive strength of 124 MPa. Cast iron, 1045 NM steel and 6061 Alum have a compressive strength of 793 MPa, 771 MPa, and 343 MPa separately. The Elastic Modulus for the testing material in the order list above is 2.73GPa, 121GPa, 214GPa, and 73.8 GPa. The Brinell-SI force units of cast iron, 1045 NM steel and 6061Al are 2207 MPa, 1913 MPa, and 981 MPa respectively. All the other results could be found in Table 1-4 in enclosures For cast iron and PMMA, the stress-strain curves in compression are different from their curves in tension while 1045 NM steel and 6061 Al have a similar stress-strain curve in compression and tension. The value of Young's modulus is similar for all testing material in tension and compression. The yield strength and the ultimate strength of cast iron and PMMA are differed compared to their value in tension. Cast iron and PMMA do not have a yield strength in tension, but they do in compression. The percentage difference for ultimate strength between tension and compression is about 137.5%. The yield and ultimate strength of steel and aluminum specimen are pretty similar, which has a percentage difference of 6.69%. However, the ultimate strength of this compression test is not well-defined, because the maximum load was set to 100kN. The ultimate strength may further increase when more load is applied. Moreover, there is a comparison of compression test and hardness test of the specimens in Figure 4 in enclosures. Form these results we concluded that cast iron is stronger than steel and aluminum in compression, but it is weaker than them in tension. Also, ductile materials in tension were found that their compressive behavior is similar to their tensile behavior. Meanwhile, brittle materials in tension will have a ductile behavior in compression. At last, the yield strength in compression is proportional to the hardness.

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