A study of the effect of average preset voltage on hardness during electrolytic surface-hardening in aqueous solution

The electrolytic surface-hardening method in aqueous solution, especially u sing pulse current, has been found to be a new development in the area of s urface-hardening technologies. Conventional surface heat-treatment processe s are carried out at high temperature, hence both the equipment and the ope rational costs are high. A review of the literature available on heat treat ment using direct-current electrolysis was attempted by the authors in a pr evious publication. This paper briefly introduces the development of this a dvanced surface heat-treatment technique that can be operated at room tempe rature, with low cost and easy control, which hence improves its competitiv eness. 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 hardness of the test-piece und er both direct-current and pulse-current conditions. Compared with direct c urrent, the test-piece can be surface hardened at a lower average preset vo ltage and with a shorter heating time. A US patent application on this new technology has been submitted in order to protect the intellectual property rights. (C) 1999 Elsevier Science S.A. All rights reserved.