SURFACE HARDENING OF STEEL IN A SOLAR FURNACE

The concentration of solar energy provides the possibility to get powe r densities high enough to produce surface modifications of materials, with low environmental impact. The present paper discusses the possib ilities of surface hardening steel by means of concentrated solar ener gy. Surface treatments have been made by using the solar furnace of th e Platafoma Solar in Almeria (Spain), which consists of a group of hel iostats and a parabolic mirror. The surface transformation hardening t reatment was performed on a 40CrMo4 steel. The paper presents the micr ostructural changes and the hardness values obtained after the solar t reatment in a superficial zone. According to the power density applied on the sample, the hardened zone varied between 1 and 10 mm deep and the treatment time was less than 30 s. (C) 1997 Elsevier Science S.A.