Abstract: A fluid is admitted into a bath having a certain temperature. The temperature of the fluid is different from that of the bath. The fluid travels through the bath so that heat transfer occurs between the bath and the fluid while, at the same time, the bath is thus caused to be agitated. The flow of the fluid into the bath is regulated in such a manner as to maintain the temperature of the bath within predetermined limits. A preferred application resides in the cooling of a bath, particularly one which is used for the heat treatment of steel wire which has been hot rolled immediately prior to the introduction thereof into the bath. Here, the fluid may be in the form of a gas upon being admitted into the bath. Alternatively, the fluid may be in the form of a liquid which vaporizes at the temperature of the bath. In this event, heat is removed from the bath partially in the form of the heat of vaporization of the liquid. It is also possible to feed both a gas and a liquid into the bath.

Abstract: A hot steel rod which issues from the last pass of a rod mill is coiled at a level above a bath of molten salt and successive coils are caused to descend in the bath toward a platform on which they accumulate to form a bundle. The coils are out of contact with each other during the initial stage of movement toward the platform for a period of time which is long enough to insure that their material undergoes desirable structural changes. The temperature of the bath is maintained within a predetermined range by an adjustable induction heater which surrounds the vessel for the bath and by circulating a stream of molten salt through one or more heat exchangers located outside of the vessel. The stream is withdrawn close to the bottom zone and is returned into the upper zone of the bath. Alternatively, the vessel may contain a mammoth pump which is operated by water and steam.