| dc.description.abstract | Have done a study on the influence of the concentration of NaOH as a cooling
medium on the mechanical properties of medium carbon steel with a heat treatment.
Heating medium carbon steel in the furnace heated up to 850 o
C and then cooling
rapidly carried to a solution of NaOH which has been varied concentrations (5%,
10%, 15%, 20%, 25%) and allowed to reach room temperature (27 o
C). HRC hardness
values of 9.4 and the tensile strength of 656.85 MPa for materials original, whereas
for materials with the process of heat treatment and cooling cent with different
concentrations of NaOH (5%, 10%, 15%, 20%, 25%) resulted in values hardness of 57
HRC, HRC 58.3, 58.5 HRC, 60 HRC, HRC 57.5 and the tensile strength of 728.50
MPa, 835.99 MPa, 987.26 MPa, 1035 MPa and 855 MPa for concentration different
NaOH (5%, 10%, 15%, 20%, 25%). Oobservations of micro structure that looks to the
material without heat treatment, namely the structure of ferrite and pearlite, while for
materials with heat treatment process and the process of cooling the pearlite structure
and martensit. From the test results, it can be concluded that the process of heat
treatment and cooling process into a solution of NaOH hardness values and tensile
strength increased, whereas at a concentration of 25% of the value of hardness and
tensile strength decrease. The observation shows the microstructure of the visible
changes in the structure of carbon steel medium which causes the hardness and tensile
strength increased and the concentration of 25% NaOH microstructure shows the
hardness and tensile strength decreased. | en_US |
