The experiment was conducted on two separate days. On the first day, six specimens were divided among groups of six with each group member taking a specimen of either differing heat treatment or steel. The samples used were of either 1018 or 1045 (AISI) steel. For each type of steel, specimens of normalized, quenched and sphereoidized steels were used, yielding six total samples to be used in experiment. Initially each sample was grinded on a belt sander to remove the defects on the outer surface. Next, each specimen was polished using alumina media on a fine cloth until the surface was clean and mirror-like in appearance. Finer flaws on the surface of each specimen were removed through polishing. Once each sample was polished to a shine, each specimen was etched in a 3% nital bath for twenty seconds and blot dried in preparation for viewing under the microscope.
On the second day each specimen was viewed under the microscope and its microstructure photographed at 200X magnification. Following inspection under the microscope, each sample was placed in a Rockwell hardness tester with a cone tip and the hardness on a Rockwell A scale was determined.
List of Apparatus:
The equipment used in this experiment includes AISI 1018 and AISI 1045 alloys, a steel belt grinder, a polishing wheel with alumina media, 3% concentration nital, a microscope, printer and a Rockwell hardness tester.
Hardness (Rockwell A) of 1018 and 1045 Steels:
Reading 3Hardness Average (Rockwell A)
Grain Size and Pearlite Percentage of Normalized Steels:
AISI TypeGrain SizeAverage Grain