DISPOSITIVO SPRAY BOX

A method for in line thermal surface treatment in a continuous casting machine associated with furnaces to heat hot charge blooms. The method being carried out in a continuous casting line consisting of a mould (13), a secondary cooling chamber (14), an extraction and straightening assembly (15) and a shearing assembly (17). The method comprising spraying the surface of the bloom (19) at the location of spray boxes (10) (110) with a pressurised water based fluid through nozzles (18) arranged to suit the bloom dimensions to create an intense concentrated cooling to produce a surface temp. between 400 and 900 deg.C after the natural tempering caused by the bloom hot core. Also claimed are a spray box (10) device in which the nozzles (18) are arranged around the bloom (19) circumference. The box having at its ends pressurised air delivered to prevent steam emission from the box structure (37) surrounding the sprays and for removing surface water from the bloom and an aspiration hood to remove the steam and air.