A plant for the continuous heat treatment of steel strips (4) or the like has a nonmagnetic insulated housing (1), in which two axially parallel unheated rollers (2, 3) are disposed at a distance from each other. To the first roller (2), the steel strip (4) or the like is supplied, which is then wound around the second roller (3) and as a secondary winding gets back to the first roller (2) through a transformer plate assembly (7) and is discharged from said second roller. The primary winding (10) with a corresponding number of turns is disposed outside the housing (1). The housing (1) is filled with a protective gas and has means (11, 12) to ensure a uniform temperature level and distribution in the housing (1).