Abstract: A gas injection system includes a tubular wall 3 capable of being thermally stressed and having a proximal extremity and a distal extremity 11, at the distal extremity, at least one extremity opening through which at least one gas is projected. A cooling is system located in the tubular wall including axial channels 12 which extend axially towards the distal extremity and in which a cooling fluid is circulated. Connecting channels 13 circumferentially join the axial channels to each other at the distal extremity of the tubular wall. The connecting channels, which circumferentially join the axial channels at the distal extremity of the tubular wall, have a rounded shape in the direction of the distal extremity.

Abstract: A blowing lance tip includes a central stirring gas-supply tube, an inner coolant-inlet tube ending, at one end thereof facing the bath, in a second front wall and having a central opening, an outer coolant-outlet tube, a heat exchange space, and a stirring gas-outlet pipe leading from each opening in the front wall, wherein the second front wall has, at the central opening, an edge which is curved in axial cross-section such that a height (H3) is defined between a leading face of said edge and the third front wall, and such that, in the heat exchange space, a predetermined minimum height (H1) is present on the side facing the central opening.

Abstract: A blowing lance tip includes a central stirring gas-supply tube, an inner coolant-inlet tube ending, at one end thereof facing the bath, in a second front wall and having a central opening, an outer coolant-outlet tube, a heat exchange space, and a stirring gas-outlet pipe leading from each opening in the front wall, wherein the second front wall has, at the central opening, an edge which is curved in axial cross-section such that a height (H3) is defined between a leading face of said edge and the third front wall, and such that, in the heat exchange space, a predetermined minimum height (H1) is present on the side facing the central opening.