A Study of the Effect of Average Preset Voltage on Effective Case Depth During Electrolytic Surface-Hardening

The electrolytic surface-hardening method in aqueous solution, especially using pulse current, has been found to be a new development in the area of surface-hardening technologies. Conventional surface heat-treatment processes are carried out at high temperature, hence both the equipment and the operational costs are high. A review of the literature available on heat treatment using direct-current electrolysis was attempted by the authors in a previous publication. This paper briefly introduces the development of this advanced surface heat-treatment technique that can be operated at room temperature, with low cost and easy control, which hence improves its competitiveness. In the investigation reported, a test-piece made of AISI 1050 steel has been surface hardened successfully by electrolysis in aqueous solution. Experimental work and analysis have been carried out in order to study the effect of the average preset voltage on the effective case depth of the test-piece under both direct-current and pulse-current conditions. Compared with direct current, the test-piece can be surface hardened at a lower average preset voltage and shorter heating time. A U.S. patent application on this new technology has been submitted in order to protect the intellectual property rights.