Systems and methods for controlling vertical folds during direct chill casting

Abstract

A method of controlling vertical folds during casting includes determining a fold control parameter of a skim dam of a casting system. The method also includes introducing molten metal into a mold cavity of a casting mold of the casting system and forming a molten sump while controlling the skim dam to have the fold control parameter. A skim dam system for a casting system includes a skim dam and a control system for selectively controlling a skim dam submergence depth of the skim dam in a molten sump.

That which is claimed: 
     
         1 . A method of controlling vertical folds during casting, the method comprising:
 determining a fold control parameter of a skim dam of a casting system; and   introducing molten metal into a mold cavity of a casting mold of the casting system and forming a molten sump while controlling the skim dam to have the fold control parameter.   
     
     
         2 . The method of  claim 1 , wherein the skim dam is a first skim dam, the mold cavity is a first mold cavity, the molten sump is a first molten sump, and the casting mold is a first casting mold, and wherein the method further comprises:
 introducing molten metal into a second mold cavity of a second casting mold of the casting system and forming a second molten sump while controlling the second skim dam in parallel with the first skim dam.   
     
     
         3 . The method of  claim 1 , wherein the fold control parameter comprises a skim dam submergence depth, and wherein controlling the skim dam comprises controlling the skim dam to be at a predetermined submergence depth within the molten sump. 
     
     
         4 . The method of  claim 3 , wherein the predetermined submergence depth is from 0 mm to 15 mm, inclusive. 
     
     
         5 . The method of  claim 3 , wherein controlling the skim dam to be at the predetermined submergence depth further comprises centering the skim dam relative to a spout of the casting system for introducing the molten metal into the mold cavity. 
     
     
         6 . The method of  claim 1 , wherein the fold control parameter comprises a skim dam shape, and wherein controlling the skim dam comprises controlling the skim dam to be a predetermined shape. 
     
     
         7 . The method of  claim 6 , wherein the predetermined shape comprises at least one of:
 a first rectangle having a first length and a first width;   a bulged rectangle having a second length and a second width;   an hour glass rectangle having a third length and a third width; or   a second rectangle having a fourth length and a fourth width, wherein the fourth length is less than the first length and the fourth width is less than the first width.   
     
     
         8 . The method of  claim 1 , wherein the fold control parameter is a first fold control parameter of the skim dam, wherein the first fold control parameter comprises a skim dam submergence depth, and wherein the method further comprises controlling a second fold control parameter of the skim dam, and wherein the second fold control parameter comprises a skim dam shape. 
     
     
         9 . The method of  claim 1 , wherein the fold control parameter is a first fold control parameter of the casting system, and wherein the method further comprises controlling a second fold control parameter of the casting system. 
     
     
         10 . The method of  claim 9 , wherein the second fold control parameter comprises at least one of a calcium level in the molten metal, an ingot head level within the mold cavity, a casting speed, or a titanium carbide level in the molten metal. 
     
     
         11 . The method of  claim 9 , wherein controlling the second fold control parameter comprises controlling a calcium level to be 70-110 ppm, inclusive. 
     
     
         12 . The method of  claim 1 , wherein the method comprises controlling vertical folds during DC casting. 
     
     
         13 . A skim dam system for a casting system, the skim dam system comprising:
 a skim dam; and   a control system configured to selectively control a skim dam submergence depth of the skim dam in a molten sump.   
     
     
         14 . The skim dam system of  claim 13 , wherein the control system comprises:
 a rotating arm rotatable about an axis;   a controller configured to rotate the rotating arm about the axis;   a support arm extending from the rotating arm, wherein the support arm is fixed relative to the rotating arm and rotatable with the rotating arm about the axis; and   a connecting arm connecting the support arm and the skim dam,   wherein rotation of the rotating arm positions the skim dam relative to the rotating arm.   
     
     
         15 . The skim dam system of  claim 14 , wherein the connecting arm is pivotably coupled to the support arm, and wherein the connecting arm is adjustable such that a distance between the support arm and the skim dam is adjustable. 
     
     
         16 . The skim dam system of  claim 14 , further comprising a stopper on the rotating arm, wherein the stopper defines an angle of rotation of the rotating arm about the axis wherein the control system further comprises a support, and wherein the stopper is configured to engage the support at first position corresponding to a maximum skim dam submergence depth of the skim dam and at a second position corresponding to a minimum skim dam submergence depth of the skim dam. 
     
     
         17 . A DC casting system comprising:
 the skim dam system of claim  23 ; and   a casting mold for receiving molten metal in the molten sump, wherein the skim dam is positionable within the casting mold.   
     
     
         18 . The skim dam system of  claim 17 , further comprising a sensor configured to detect a position of the skim dam, wherein the control system is configured to control the skim dam submergence depth of the skim dam based on the detected position from the sensor. 
     
     
         19 . A casting system comprising:
 a plurality of casting molds for receiving molten metal;   a plurality of skim dams, wherein each skim dam is positionable within a corresponding casting mold; and   a control system configured to jointly control a skim dam submergence depth of each skim dam in a molten sump in the corresponding casting mold.   
     
     
         20 . The casting system of  claim 19 , wherein the control system comprises:
 a controller;   a rotating arm;   a plurality of support arms extending from the rotating arm; and   a plurality of connecting arms, each connecting arm connected to a corresponding support arm and a corresponding skim dam,   wherein rotation of the rotating arm positions the plurality of skim dams relative to the rotating arm.