Twin-belt continuous casting method providing control of the temperature operating conditions at the casting belts

In a twin-belt casting process wherein the casting region is defined between opposed portions of a pair of revolving endless flexible casting belts and molten metal is introduced into the casting region to be carried along between the travelling belts as it solidifies and wherein the belts travel partially around respective nip rolls positioned upstream from the casting region and said nip rolls have deep circumferential grooves with intervening tall narrow ridges adapted to engage the reverse surfaces of the casting belts travelling around the respective nip rolls, the invention comprising the steps of:

• applying heating to said casting belts as they are revolving before the respective belts reach the casting region for pre-heating the belts, and
• insulating the perimeters of said narrow ridges for reducing the amount of conductive heat transfer occurring between said belts and said nip rolls for reducing the flow of heat from the belts into the nip rolls.

The method of casting molten metal in a casting region defined between opposed portions of a pair of revolving endless flexible casting belts wherein the molten metal is brought into contact with the front faces of the casting belts and is carried along between the front faces of the belts in the casting region while liqiud coolant is applied to the reverse surfaces of the belts to remove heat from the molten metal, comprising the steps of:

• applying intensive heating to the respective belt ahead of the position where the molten metal is brought into contact with the belt for pre-heating the belt, and
• applying hot liquid to the reverse surfaces of the edge portions of the belt on opposite sides of the casting region for maintaining the edge portions at elevated temperatures.

The method of casting molten metal in a casting region defined between opposed portions of a pair of revolving endless flexible metal casting belts wherein the molten metals is introduced into the casting region and is carried downstream through the casting region by the moving belts while the metal is solidifying, comprising the steps of:

• elevating the temperature of the main central portion of at least one of said metal casting belts before the main central portion of said belt encounters the molten metal in the casting region, and
• elevating the temperature of the two edge portions of said metal belt to higher temperature levels than said main central portion before said two edge portions pass adjacent to the casting region,
• said two edge portions being elevated to temperature levels at least as great as the mean temperature level of the main central portion of the metal belt in the casting region.

The method of casting molten metal in a casting region defined between opposed portions of a pair of endless flexible casting belts wherein the molten metal is introduced at an entrance to the casting region and thereafter the molten metal travels downstream from the entrance while solidifying between the front faces of the two casting belts and wherein the heat from the solidifying molten metal is withdrawn by applying liquid coolant to the reverse surfaces of the two casting belts, comprising the steps of:

• directing intensive radiant heat energy onto the front faces of the respective revolving casting belts for elevating their temperature before the respective casting belts reach the entrance to the casting region, and
• controlling the application of the liquid coolant to the reverse surfaces of the respective casting belts for initially applying the coolant to the reverse surfaces of the belts only a small distance from the position where the molten metal initially comes into contact with the front face of the respective casting belt.

The method of casting molten metal in a casting region defined between opposed portions of a pair of revolving endless flexible casting belts wherein the belts are curved partially around respective nip rolls with the reverse surfaces of the belts engaging the nip rolls and thereafter the belts travel downstream from the nip rolls with portions of the belts travelling in spaced opposed relationship defining the casting region between their front faces and molten metal is adjacent to the front face of the opposed portions of the casting belts in the casting region, comprising the steps of:

• applying intensive radiant heat energy to the front faces of the two casting belts as they move toward the nip rolls for elevating the temperatures of the belts before they reach the nip rolls, and
• applying further intensive radiant energy to the front faces of the two casting belts as they curve around the nip roll.

The method of casting molten metal in a casting region defined between opposed portions of a pair of revolving endless flexible casting belts wherein the belts are curved partially around respective nip rolls with the reverse surfaces of the belts enging the nip rolls in which there are deep grooves in the nip rolls positioned adjacent to the reverse surfaces of the casting belts as they curve around the respective nip rolls and thereafter the belts travel downstram from the nip rolls with portions of the belts travelling in spaced opposed relationship defining the casting region between their front faces and molten metal is adjacent to the front faces of the opposed portions of the casting belts in the casting region, comprising the steps of:

• heating the two casting belts as they move toward the nip rolls;
• and
• injecting hot fluid into the deep grooves of the nip rolls beneath the reverse surfaces of the casting belts for continuing the heating of the two casting belts as they curve around the respective nip rolls.

The method of casting molten metal in a casting region defined between opposed portions of a pair of endless flexible casting belts wherein the molten metal is introduced at an entrance to the casting region and thereafter the molten metal travels downstream from the entrance while solidifying between the front faces of the two casting belts and wherein the heat from the solidifying molten metal is withdrawn by applying liquid coolant to the reverse surfaces of the two casting belts, comprising the steps of:

• heating a first zone of at least one of the revolving casting belts before the respective casting belt reaches the entrance to the casting region to a mean temperature at least equal to the mean temperature of the portion of the casting belt defining the casting region, said first zone spanning transversely across the main central portion of the belt for a width equal to the width of the casting region, and
• heating second and third zones of said revolving casting belt before the respective casting belt reaches the entrance to the casting region to a mean temperature different from the mean temperature of said first zone, said second and third zones spanning transversely across the respective edge portions of each belt which will travel outside of the casting region as they travel along near the casting region.

The method of continuously casting molten metal using a pair of revolving endless flexible casting belts of metal whose front metal faces are coated with insulative coating material wherein portions of the belts travel along in spaced relationship for defining a casting region between their coated front faces for casting molten metal in the casting region and wherein the reverse surfaces of the belts near the casting region are cooled with liquid coolant, including the steps of:

• directing intensive radiant heat energy onto the insulative coating material of the respective revolving casting belts before their arrival at the casting region for elevating the mean temperatures of the casting belts ahead of the casting region to levels above their mean temperatures in the casting region, and
• initially applyling liquid coolant to the reverse surfaces of the belts only a small distance from the position where the molten metal initially comes into contact with their coated front faces for minimizing the cooling effect of the applied coolant upon the mean temperature of the respective casting belts.

The method of continuously casting molten metal using a pair of revolving endless flexible casting belts of metal whose front faces are coated with insulative coating material as claimed in clalm 15;

• wherein the belts are curved partially around respective nip rolls with the reverse surfaces of the belts engaging the nip rolls ahead of the casting region, including the step of:
• insulating the portions of the nip rolls engaged by the reverse surfaces of the belts for minimizing the transmission of heat from the reverse surfaces of the belts into the nip rolls.

The method of continuously casting molten metal using a pair of revolving endless flexible casting belts of metal whose front metal faces are coated with insulative coating material wherein portions of the belts travel along in spaced relationship for defining a casting region between their coated front faces for casting molten metal in the casting region and wherein the reverse surfaces of the belts near the casting region are cooled with liquid coolant, including the steps of:

• directing intensive radiant heat energy onto the insulative coating material of the respective revolving casting belts before their arrival at the casting region for elevating the temperatures of the interfaces between the metal front faces and the insulative coating material of the respective belts to levels ahead of the casting region which are equal to the temperature levels occurring at these interfaces after the molten metal has come into contact with their coated front faces, and
• initially applying liquid coolant to the reverse surfaces of the belts only a small distance from the position where the molten metal initially comes into contact with their coated front faces for minimizing the cooling effect of the applied coolant upon the temperature levels of these interfaces in the respective casting belts.