Mechanical Properties Analysis of Medium Carbon Steel Heated at 850°C by Quenching in NaOH Solution

Abstract

The aim of this study is to analyze the mechanical properties of carbon steel
medium by quenching in NaOH solution. Heating medium of the carbon steel in a heating
furnace is 850°C. The cooling process in NaOH solution was varied in concentration of
NaOH (5%, 10%, 15%, 20%, 25%), and the sample was allowed to reach room temperature
(27°C). The original medium carbon steel hardness value is 9.4 HRC and the tensile
strength value is 656.85 MPa, while for materials with heat treatment processes and cooling
processes with different concentrations of NaOH (5%, 10%, 15%, 20%, 25%) resulted in
hardness values of 57 HRC, 58.3 HRC, 58.5 HRC, 60 HRC, 57.5 HRC and tensile strength
values of 728.50 MPa, 835.99 MPa, 987.26 MPa, 1035 MPa, and 855 MPa for different
concentrations of NaOH (5%, 10%, 15%, 20% , 25 %). Analysis of XRD crystalline
structure on medium carbon steel with intermediate carbon steel from the three highest
peaks of each test sample was found that its orthorhombic crystal structure in which lattice
parameters a, b, and c.