EXPERIMENT 1:IMPACT TESTINGOBJECTIVE:To determine the impact strength of MaterialsAPPARATUS:Impact Tester Machine STR08PROCEDURE:1.The test piece is placed on the supports so that the break indentation faces thedirection of the pendulum swing and that the indent is exactly in the middle of thesupports.2.Raise the pendulum to the start point.3.Set the pointer to 50 joules, i.e. straight down.4.Release the pendulum by turning the black knob, top right.KEEPS HANDSCLEAR.The test piece is broken off.5.Stop the pendulum by lifting the friction brake. Be sure that the pendulum is atstandstill before removing the test pieces.6.The energy consumed when breaking the test piece can now be read directly fromthe scale, indicated by the pointer.1
Influenceof C% onimpactenergyversustemperature for steels(Smith & Hashemi- 4thEd)2
EXPERIMENT 2:MICROSTRUCTURE AND HARDNESS OF Fe-CALLOY STEELSOBJECTIVE:Toexamine the microstructure and to measure the hardness of slowlycooled Fe-C alloy steels containing 3 different wt% of carbon. The wt% of carbon for each sample will be determined based on theobservation from this experiment.APPARATUS:Grinding and Polishing machine, Microscope with ImagingWorkstation and Digital Micro Vickers Hardness Tester.PROCEDURE:1.Preparation of steel samplesi.Polish/wash/dry: The three steel samples are mounted individually withepoxy. Polish, wash and dry specimens, until no gross polishing marks arevisible.ii.Etch: Delineate the mirror-finish sample using 2% Nital solution (2% byvolume of concentrated nitric acid in methyl alcohol)2.Microstructure examinationi.After etching, examine the specimens microscopically and identify theregions of ferrite (light) and pearlite (dark and lamellar).ii.Estimate the relative amounts of ferrite and pearlite in each sample. Sketchthe microstructures of the three steel samples. Label the different phasespresent and quote the total magnification (Objective x Prism (if any) xEyepiece).iii.By applying the Lever Rule, estimate the wt% of carbon in each of thesteels sample based on the Fe-C phase diagram.3.Hardness measurementi.Measure the Vikers hardness value of each specimen, taking three readingsfor each specimen, and plot into graph with the consideration ofuncertainty in the data using error bars.