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The carburizing process involves adding carbon components to the steel surface at an austenite temperature to harden it. The goal of this study was to see how the process of carburizing ST 60 steel at 825°C for 4 hours using wood charcoal that had been converted into carbon affected the microstructure and surface hardness. Microstructure testing is used to detect the steel's phase after it has been carburized. The goal of hardness testing is to assess the material's hardness following the carburizing process. The carbon sieving procedure produced a dry carbon size of 100 mesh with a particle size of 554.621m2 and a wet carbon size of 500 mesh with an average area of 113.542m2 of carbon particles. Based on the findings of the tests, it can be assumed that following the carburizing process, the number of carbon particles would decrease. Carbon was lost at a rate of 33.58 percent, with an average particle area of 554.621m2. Carbon with an average particle area of 113.542m2 was lost by 9.91 percent. According to the Vickers hardness test, the raw material's average hardness from points 1 to 5 is 280.42kg/mm2. Steel with a hardness of 1-5 points is carburized with an average area of 554.621m2 carbon particles with a density of 214.56kg/mm2. The area of carbon particles in carburizing steel is 113.542m2, and the average hardness value is 245kg/mm2. [ABSTRACT FROM AUTHOR]

In this work, the effect of the Ni underlayer with different thicknesses on the mechanical properties of Cu surface was studied. A laminated structure of Ni/Cu layer was prepared using electroplating on carbon steel substrates. The nickel layer was firstly plated on the steel using a current voltage of 2.3 V and varied plating times using 30, 60, 90, 120 and 150 minutes. The copper layer was subsequently electroplated on the nickel surface using a fixed current voltage of 1.9 V and plating time of 30 minutes. The result showed that XRD pattern observed on the surface of Ni/Cu coating indicates the formation of Cu single phase instead of Ni/Cu alloy. Application of plating time variations on the Ni underlayer using 30, 60, 90, 120 and 150 minutes produced an average thickness of Ni underlayer with 19.9, 48.4, 50.1, 62.1 and 64.9 µm, respectively. The thickness of Cu as the outer layer for different thickness of Ni was kept constant at approximately 23.66 µm. The hardness measurement on the Cu underlayed by Ni deposited using different plating times indicated that the hardness of Cu was 91.63, 93.20, 97.93, 102.60 and 106.1 HV, respectively. Whereas, the specific wear rates of Cu were 6.59 × 10-6, 6.11 × 10-6, 5.99 × 10-6, 3.63 × 10-6 and 3.55 × 10-6 mm3/kg.m, respectively. The present study showed that the mechanical properties of Cu layer surface with a fixed layer thickness were influenced by the application Ni underlayer with different thicknesses. An increase of Ni underlayer thickness has increased the hardness and specific wear rate of the Cu layer. [ABSTRACT FROM AUTHOR]

In this work, a laminated structure of Cr-Ni coating was prepared using electroplating on carbon steel substrates. Two baths of chrome and nickel electrolyte solutions were prepared to deposit laminated Cr and Ni layers. Chrome was firstly plated on a steel substrate in constant routes whereas nickel was subsequently electroplated on the Cr coating using varied plating times. The effect of Ni plating time on the thickness, hardness and wear specific of the Ni layer was investigated. The results show that an increase of plating times increased the thickness and hardness of the Ni layer, but reduced the wear specific. This study showed that Ni can be a potential candidate as a material replacement for chromium plating maintenance. [ABSTRACT FROM AUTHOR]