ST 42 steel is one kind of low carbon steel. In general, low-carbon steel is ductile, tough, relatively cheap, and has good weldability and machinibilty. However, one of the weaknesses of low carbon steel is the low hardness values and high corrosion rate. One effort to improve the corrosion resistance of the steel is electroplating.
In this research, electroplating process used the current variations of 2A, 4A and 6A and the time variations of 20 minutes, 30 minutes and 40 minutes. The hardness testing used vickers method and the corrosion testing used testing corrosion rate testing equipment of electrode three cell type with PGS-201T potensiostat and 0.5% NaCl corrosive media. The test results showed that the coating formed on the electroplating process was strongly effected by the time and flow coating process.
The results of hardness testing on the surface after electroplating process tended to increase along with a thick layer of chromium produced therefore the surface hardness value decreased. The highest hardness value was 551,9 VHN at 2A current and 20 minutes. The values corrosion rate decreased along the increasing time of electroplating process. The lowest corrosion rate was 1,35 mmpy at the time of 40 minutes.
Keywords: electroplating, current, time, hardness, corrosion rate