Continuous casting process of metal

Abstract

A continuous casting process of a steel semi-product is provided. The process includes a step of casting using a hollow jet nozzle located between a tundish and a continuous casting mould. The nozzle includes, in its upper part, a dome for deflecting the liquid metal arriving at the inlet of the nozzle towards the internal wall of the nozzle, defining an internal volume with no liquid metal. A simultaneous step of injecting powder through a hole of the dome occurs. The powder has a particle size of 200 μm or less. The dome includes a first device to inject the powder without any contact with the dome and a second device to avoid sticking or sintering of the powder onto the first device.

What is claimed is: 
     
         1 . A continuous casting process of a steel semi-product comprising:
 casting, using a hollow jet nozzle located between a tundish and a continuous casting mould, the nozzle including, in an upper part, a dome for deflecting liquid metal arriving at an inlet of the nozzle towards an internal wall of the nozzle, thereby defining an internal volume with no liquid metal; and   injecting, simultaneously, powder through a hole of the dome, the powder having a particle size of 200 μm or less, the dome including a first device to inject the powder without any contact with the dome, the first device including a hollow body, and a second device to apply mechanical stresses to the powder particles in contact with the hollow body.   
     
     
         2 . The continuous casting process according to  claim 1 , wherein the hollow body is rotated about a longitudinal axis. 
     
     
         3 . The continuous casting process according to  claim 1 , wherein the second device vibrates the hollow body inside the hole. 
     
     
         4 . The continuous casting process according to  claim 3 , wherein the second device includes a mechanical vibrator or an ultrasound vibrator. 
     
     
         5 . The continuous casting process according to  claim 3 , wherein the second device vibrates the hollow body inside the hole at a frequency between 50 and 500 HZ. 
     
     
         6 . The continuous casting process according to  claim 1 , wherein the second device includes an insulating layer disposed inside the hole between the dome and the hollow body to create a thermal barrier, the first device being surrounded by the insulating layer. 
     
     
         7 . The continuous casting process according to  claim 6 , wherein the insulating layer includes ceramic fibers. 
     
     
         8 . The continuous casting process according to  claim 6 , wherein the insulating layer extends at least over a length of the hole, the length being taken along a longitudinal axis of the hole 
     
     
         9 . The continuous casting process according to  claim 1 , wherein the hollow body is a tube with a circular section. 
     
     
         10 . The continuous casting process according to  claim 9 , wherein an inner diameter of the tube ranges from 8 to 30 mm. 
     
     
         11 . The continuous casting process according to  claim 1 , wherein a powder feeder is partly disposed in the hollow body. 
     
     
         12 . The continuous casting process according to  claim 11 , wherein the powder feeder goes through a support arm of the dome. 
     
     
         13 . The continuous casting process according to  claim 1 , wherein said hollow body comprises a double wall, and the process comprises, during the injecting, circulating a cooling gas inside the double wall via an inlet on an end of the double wall and exhausting the cooling gas from the double wall via an outlet on said end of the double wall. 
     
     
         14 . The continuous casting process according to  claim 13 , wherein the double wall further comprises an outer wall and an inner wall, the powder being in contact with an internal surface of the inner wall during the injecting. 
     
     
         15 . The continuous casting process according to  claim 14 , wherein an external surface of the inner wall and an internal surface of the outer wall define a gas input channel and a gas outlet channel, the gas circulating in the gas input channel in a first direction and the gas circulating in the gas outlet channel in a second direction opposite to the first direction. 
     
     
         16 . The continuous casting process according to  claim 15 , wherein the gas circulating in the gas input channel is in contact with the external surface of the inner wall and with the internal surface of the outer wall, and the gas circulating in the gas outlet channel is in contact with the external surface of the inner wall and with the internal surface of the outer wall. 
     
     
         17 . The continuous casting process according to  claim 15 , further comprising a plurality of transverse walls extending radially from the inner wall to the outer wall. 
     
     
         18 . The continuous casting process according to  claim 14 , wherein the outer wall of the double wall is made of one material and has an external surface, the external surface of the outer wall being arranged away from an inner surface of the hole of the dome, the external surface of the outer wall and the inner surface of the hole of the dome delimiting between them a space. 
     
     
         19 . The continuous casting process according to  claim 13 , wherein the cooling gas circulates in the double wall with a flow rate ranging from 10 to 30 m 3 /h. 
     
     
         20 . The continuous casting process according to  claim 13 , wherein the inlet and the outlet of the double wall are arranged out of the dome.