Stopper Rod for Delivering Gas Into a Molten Metal

Abstract

The invention relates to a stopper rod adapted to deliver gas during pouring of molten metal comprising a stopper body having an internal chamber and a gas discharge port, a bore connecting the internal chamber to the gas discharge port, the internal chamber and the bore defining a gas passageway. According to the invention, the walls of the gas passageway are provided with a layer of a material which will not produce carbon monoxide at the temperature of use. The stopper rod of the invention does not contaminate the gas passing therethrough.

1 - 9 . (canceled)  
   
   
       10 . A stopper rod adapted to deliver gas during pouring of molten metal comprising a stopper body including walls defining a gas passageway fluidly connected to a gas discharge port, the walls comprising a layer that will not produce carbon monoxide at use temperature.  
   
   
       11 . The stopper rod of  claim 10 , wherein the layer comprises a liner copressed with the body.  
   
   
       12 . The stopper rod of  claim 10 , wherein the layer comprises a coating applied on the walls of the gas passageway.  
   
   
       13 . The stopper rod of  claim 10 , wherein the walls include a thickness and the layer extends through essentially the thickness of the walls.  
   
   
       14 . The stopper rod of claim  1 , wherein the layer extends beyond a lowest point reached by a metal rod that attaches the stopper to a rigging device.  
   
   
       15 . The stopper rod of claim  1 , wherein the layer comprises a material selected from a group consisting of materials that do not contain carbon; materials consisting essentially of non-reducible refractory oxides; materials that react with carbon monoxide, and mixtures thereof.  
   
   
       16 . The stopper rod of claim  1 , wherein the layer comprises 60-88 wt. % alumina, 10-20 wt. % graphite, and 2-10 wt. % silicon carbide.  
   
   
       17 . A stopper rod assembly adapted to deliver gas during pouring of molten metal, the assembly comprising a stopper rod including a stopper body and walls defining a gas passageway fluidly connected to a gas discharge port, the walls comprising a layer that will not produce carbon monoxide at use temperature; a metal rod attaching the stopper rod to a rigging device, the metal rod extending into the gas passageway beyond a highest point of the layer.  
   
   
       18 . The assembly of  claim 17 , wherein a sealing gasket extends around a lower end of the metal rod.  
   
   
       19 . A stopper rod adapted to deliver gas during pouring of molten metal comprising a stopper body having an internal chamber and a gas discharge port, a bore fluidly connecting the internal chamber to the gas discharge port, the internal chamber and the bore defining a gas passageway including walls comprising a layer that will not produce carbon monoxide at the temperature of use.