Tubular die for the continuous casting of a thin-walled tube

Claim 1

A tubular die arrangement for a continuous tube casting installation, comprising: a pouring basin (1) for molten metal provided with a lower outlet orifice (4), a tubular die (6) mounted to the basin and depending downwardly from the outlet orifice, a cooling jacket (15) mounted below the basin along an extension of an inner wall of the orifice, and a heated core (8) which together with the die defines a narrow tubular casting space (10) coaxial with respect to the orifice, the die comprising a thick cylindrical body (7) surrounded by the cooling jacket, and an integral head portion (17) projecting upwardly into the orifice, said head portion being composite and comprising: (a) at least one narrow annular inner lip (22,32,42,46) of relatively high thermal conductivity material having an inner surface (26) forming a continuous extension of an inner surface (26) of the die body, said lip being joined to the die body at a plane of contact (P) between the basin and the cooling jacket, and (b) at least one insulating ring (24,34,45,48,49) of relatively low thermal conductivity material surrounding the lip and in direct contact with the body, said composite head portion constituting a relatively high resistance heat transfer path from the basin to the cooling jacket, whereby said lip is maintained at a relatively high temperature to thereby prevent premature molten metal solidification and obstruction of an entrance portion of said casting space.