Instructor Dr Mahdi NorouziSeptember 23, 2021AbstractThis lab experiment was done to measure the hardness of nine metal samples. The kind of metal was known for each of the samples. The hardness test was three times on each sample then the average values of hardness for each sample were calculated and were compared with published hardness values for each sample. Then the conditions of each sample were determined by the comparison of experimental values and published values as whether the samples had gone through a hardening process. The hardest of the samples was determined to be ductile cast iron.IntroductionLaboratory Module 4 Hardness TestingbyAdam BrewSchool of Engineering Grand Valley State UniversityLab ReportEGR 251- Material Science & Engineering LabSection 102Instructor Dr Mahdi NorouziSeptember 23, 2021AbstractThis lab experiment was done to measure the hardness of nine metal samples. The kindof metal was known for each of the samples. The hardness test was three times on each samplethen the average values of hardness for each sample were calculated and were compared withpublished hardness values for each sample. Then the conditions of each sample were determinedby the comparison of experimental values and published values as whether the samples had gonethrough a hardening process. The hardest of the samples was determined to be ductile cast iron.IntroductionThe overarching objectives of this laboratory module were to first introduce the hands-onexperience of the measurement of the hardness of engineering materials. Then to introduce thedifferent types of metals and their distinguishing characteristics. Then to be able to know thedifferences in the mechanical properties of different types of engineering materials. Then to beable to see how alloy composition effects the mechanical properties of metal alloys. Then to beable to study the effects of metal product form and condition on mechanical properties. Also tobe able to determine the effects of elemental chemical composition on the hardness of metals.Then to finally be able to use hardness as an index of mechanical properties to relate themechanical properties of metals to their areas of application.Experimental ProcedureThe samples of engineering materials were inspected to insure the readiness of the samples forharness testing. Then the hardness tester was examined to see that it was in good operatingcondition. Then the harness was tested for calibration using a standard hardness test block. Thenthe hardness tester was set up for Rockwell hardness B scale. Then the hardness was conductedthree time per sample ensuring that each test was done away from prior testing sites and awayfrom the edge of the sample. Then the mean, range, and standard deviation for each sample wascalculated.Results The results for the hardness testing of each engineering material along with the publishedhardness values for each sample were recorded in Table 1. Along with the published values ofthe hardness of each sample the chemical composition for each sample was found. The possiblechemical composition of each sample can be seen in Table 2.Table 1- Experimental and Published Values for given Engineering Material SamplesMaterialTrial1Trial2Trial3CalculatedMean RangeStandardDeviationPublishedHardness(Rockwell B)Percent ErrorbetweenExperimental andPublished ValuesAl Alloy2024 81.5 79.8 77.8 79.700 3.7 1.852 80 0.375Al Alloy6061 53.3 53.8 53.9 53.667 0.6 0.321 60 10.556Tool Steel4140 95.3 94.4 96 95.233 1.6 0.802 105 9.302Ductilecast iron 96.4 95.1 94.8 95.433 1.6 0.850 96 0.590Gray castiron 96 93.6 95.1 93.867 2.4 1.222 100 6.133Mild SteelC1018 95.2 92.8 93.6 93.867 2.4 1.222 92 2.029PhosphorBronze 63.6 70.4 64.3 66.100 6.8 3.740 73 9.452Copper 28.7 23.4 29.8 27.300 6.4 3.422 51 46.471Stainlesssteel 84.7 86.2 84.7 85.200 1.5 0.866 88 3.182Brass 66.7 68.4 67.2 67.433 1.7 0.874 70 3.667Table 2 – Possible Chemical Composition ofeach SampleMaterialAlloyingelementWt. % insampleAl Alloy 2024Cr <= 0.10Cu 3.8 - 4.9Fe <=0.50Mg 0.30 - 0.90Mn <= 0.05Si <= 0.50Ti <= 0.15Zn <= 0.25Al Alloy 6061Cr 0.04 - 0.35Cu 0.15 - 0.40Fe <= 0.70Pb <= 0.003Mg 0.80 - 1.2Mn <= 0.15Si 0.40 - 0.80Ti <= 0.15Zn <=0.25Tool Steel 4140 C 0.38 - 0.43Cr 0.80 - 1.1Mn 0.75 - 1.0Mo 0.15 - 0.25P <= 0.035Si 0.15 - 0.30Fe 96.785 - 97.77S <= 0.040Ductile castironC 2.0 - 4.1Ce 0.0050 - 0.20Mn 0.10 - 4.5Mo 0 - 2.5Ni 0.050 - 3.6Fe 53 - 96.2Si 1.0 - 6.0Cu 0.020 - 1.0Sn 0.10 - 0.25Gray cast ironC 2.6 - 4.0Cr 0.050 - 2.5Cu 0.050 - 7.5Fe 65.1 - 95.3Mg 0.40 - 0.070Mn 0.10 - 1.5 Mo 0.050 - 0.60Ni 0.050 - 17.5P 0.015 - 0.20Si 1.0 - 3.0S 0.0050 - 0.15Mild SteelC1018C 0.14 - 0.20Fe 98.81 - 99.26Mn 0.60 - 0.90P <= 0.040S <= 0.050PhosphorBronzeCu 98.75Fe <= 0.10Pb <= 0.050P <= 0.35Sn 1.0 -1.7Zn <= 0.30CopperCu 96.4 - 100P0.0010 -0.0050Stainless steelC 0 - 2.8Cr 0.25 -57Fe 5.5 - 96.9Mn 0.035 - 16Cu 0.050 - 14Co 0.050 - 21N 0.0050 - 11BrassCu 55 - 95Pb 0.050 - 8.0Si 0.0050 - 4.5Zn 4.0 - 43.5DiscussionSome of the sources of error in the hardness measurements in this lab module were that if thesurface on the given sample was not flat would cause the measurement of the hardness of thesample to be off. Also, if testing was done to close to a previous test site of the material canaffect how much error is caused when a source of error was encountered. There were differencesin the hardness values for different metals . When comparing ductile cast iron to copper thedifference in hardness was 67.98 RHB. But if comparing 4140 steel to ductile cast iron thedifference was on average 0.2 RHB. The hardness values for metals and alloys in the samesubgroups and alloy family families are different. The difference is causes because for the groupof steels it can depend on the carbon content or is the material has gone through a heat treatmentprocess. For other metals the hardness of the material can depend on the amount of alloyingmetals in the sample or if the metal has gone through a hardening process. Based on the hardnessresults suggest the conditions of the different materials showed that all of sample besides thecopper sample were most likely not heat treated because they were below the values of thepublished hardness’s, but the values were still close published values. Were as the copper sampleshowed to be well the below the published values showing that it was most likely annealed to beat the lowest hardness. The differences between the experimental hardness results