Laboratory Module 4 Hardness Testing by Adam Brew School of Engineering Grand Valley State University EGR 251 Material Science Engineering Lab Lab Report Section 102 Instructor Dr Mahdi Norouzi September 23 2021 Abstract This 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 Introduction The overarching objectives of this laboratory module were to first introduce the hands on experience of the measurement of the hardness of engineering materials Then to introduce the different types of metals and their distinguishing characteristics Then to be able to know the differences in the mechanical properties of different types of engineering materials Then to be able to see how alloy composition effects the mechanical properties of metal alloys Then to be able to study the effects of metal product form and condition on mechanical properties Also to be 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 the mechanical properties of metals to their areas of application Experimental Procedure The samples of engineering materials were inspected to insure the readiness of the samples for harness testing Then the hardness tester was examined to see that it was in good operating condition Then the harness was tested for calibration using a standard hardness test block Then the hardness tester was set up for Rockwell hardness B scale Then the hardness was conducted three time per sample ensuring that each test was done away from prior testing sites and away from the edge of the sample Then the mean range and standard deviation for each sample was calculated Results Al Alloy Al Alloy Tool Steel Ductile Gray cast Mild Steel Phosphor Stainless The results for the hardness testing of each engineering material along with the published hardness values for each sample were recorded in Table 1 Along with the published values of the hardness of each sample the chemical composition for each sample was found The possible chemical composition of each sample can be seen in Table 2 Table 1 Experimental and Published Values for given Engineering Material Samples Trial Trial Trial Calculated Standard Hardness Experimental and Material 1 2 3 Mean Range Deviation Rockwell B Published Values Percent Error Published between 2024 81 5 79 8 77 8 79 700 3 7 1 852 6061 53 3 53 8 53 9 53 667 0 6 0 321 4140 95 3 94 4 96 95 233 1 6 0 802 105 9 302 cast iron 96 4 95 1 94 8 95 433 1 6 0 850 96 0 590 iron 96 93 6 95 1 93 867 2 4 1 222 100 6 133 C1018 95 2 92 8 93 6 93 867 2 4 1 222 Bronze 63 6 70 4 64 3 66 100 Copper 28 7 23 4 29 8 27 300 steel 84 7 86 2 84 7 85 200 Brass 66 7 68 4 67 2 67 433 6 8 6 4 1 5 1 7 3 740 3 422 0 866 0 874 80 60 92 73 51 88 70 0 375 10 556 2 029 9 452 46 471 3 182 3 667 Table 2 Possible Chemical Composition of each Sample Alloying Wt in Material element Al Alloy 2024 Al Alloy 6061 Tool Steel 4140 sample 0 10 3 8 4 9 0 50 0 30 0 90 0 05 0 50 0 15 0 25 0 04 0 35 0 15 0 40 0 70 0 003 0 80 1 2 0 15 0 40 0 80 0 15 0 25 0 38 0 43 0 80 1 1 0 75 1 0 0 15 0 25 0 035 Cr Cu Fe Mg Mn Si Ti Zn Cr Cu Fe Pb Mg Mn Si Ti Zn C Cr Mn Mo P Si Fe S C Ce Mn Mo Ni Fe Si Cu Sn C Cr Cu Fe Mg Mn Mo Ni P Si S C Fe Mn P 0 15 0 30 96 785 97 77 0 040 2 0 4 1 0 0050 0 20 0 10 4 5 0 2 5 0 050 3 6 53 96 2 1 0 6 0 0 020 1 0 0 10 0 25 2 6 4 0 0 050 2 5 0 050 7 5 65 1 95 3 0 40 0 070 0 10 1 5 0 050 0 60 0 050 17 5 0 015 0 20 1 0 3 0 0 0050 0 15 0 14 0 20 98 81 99 26 0 60 0 90 0 040 Ductile cast iron Gray cast iron Mild Steel C1018 S Cu Fe Pb P Sn Zn Cu P C Cr Fe Cu Co N Cu Pb Si Zn 0 050 98 75 0 10 0 050 0 35 1 0 1 7 0 30 96 4 100 0 0010 0 0050 0 2 8 0 25 57 5 5 96 9 0 050 14 0 050 21 0 0050 11 55 95 0 050 8 0 0 0050 4 5 4 0 43 5 Phosphor Bronze Copper Brass Stainless steel Mn 0 035 16 Discussion Some of the sources of error in the hardness measurements in this lab module were that if the surface on the given sample was not flat would cause the measurement of the hardness of the sample to be off Also if testing was done to close to a previous test site of the material can affect how much error is caused when a source of error was encountered There were differences in the hardness values for different metals When comparing ductile cast iron to copper the difference in hardness was 67 98 RHB But if comparing 4140 steel to ductile cast iron the difference was on average 0 2 RHB The hardness values for metals and alloys in the same subgroups and alloy family families are different The difference is causes because for the group of steels it can depend on the carbon content or is the material has gone through a heat treatment process For other metals the hardness of the material can depend on the amount of alloying metals in the sample or if the metal has gone through a hardening process Based on the hardness results suggest the conditions of the different materials showed that all of sample besides the copper sample were most likely not heat treated because they were below the values of the published hardness s but the values were still close published values Were as the copper sample showed to be well the below the published values showing that it was …