Twin-belt continuous caster with containment and cooling of the exiting cast product for enabling high-speed casting of molten-center product

In a method for achieving high-speed casting in a continuous casting installation for steel wherein a twin-belt casting machine having upper and lower casting belts revolving respectively around upper and lower exit pulley rolls is producing steel cast product for feeding into a regular rolling mill having minimum rolling-speed requirements, wherein said revolving casting belts define a planar moving mold casting region between them, wherein the respective revolving casting belt travels past a final backup roller located upstream from the respective exit pulley roll and wherein the cast steel product is discharged from between the revolving casting belts at an exit located between said exit pulley rolls, the method comprising the steps of:

• steering each revolving casting belt by laterally skewing the respective exit pulley roll around which the casting belt is revolving,
• said lateral skewing of the exit pulley roll being in coplanar relationship with said planar moving mold casting region for enabling each revolving casting belt to hug the product being cast in the region between said final backup roller and the respective exit pulley roll,
• applying opposed rolling contact to the cast steel product at a bulge-resisting-effective distance from said exit,
• said bulge-resisting-effective distance preventing significant bulging of a solidified shell of said cast steel product enclosing a molten steel interior, and
• directing water spray onto said solidified shell between said exit and said opposed rolling contact and aiming said water spray in an upstream direction at an angle inclined toward said exit, said angle being relative to said solidified shell and being an acute angle greater than about ten degrees.

In a continuous casting installation for steel wherein a twin-belt casting machine having upper and lower casting belts revolving respectively around upper and lower exit pulley rolls is producing steel cast product for feeding into a regular rolling mill having minimum rolling-speed requirements, wherein the respective revolving casting belt travels past a final backup roller located upstream from the respective exit pulley roll, wherein the cast steel product is issuing from between the revolving casting belts at an exit between said exit pulley rolls and wherein said cast steel product includes a solidified shell enclosing a molten steel interior, a system for achieving high-speed casting by said twin-belt casting machine for meeting the minimum rollng-speed requirements of said regular rolling mill comprising:

• means for causing each casting belt to hug the product being cast in the region between said final backup roller and the respective exit pulley roll,
• a pair of opposed rollers in rolling contact with said solidified shell downstream from said exit,
• said pair of opposed rollers being positioned at a bulge-resisting-effective distance from said exit for resisting significant bulging of said solidified shell,
• spray nozzle means positioned above and below the cast steel product for applying cooling sprays of water to said solidified shell from above and from below in a region between said exit and said pair of opposed rollers, and
• said spray nozzle means being aimed toward said solidified shell in an aiming direction at an acute angle relative to said solidified shell and said aiming direction being inclined upstream toward said exit for cooling the solidified shell adjacent to said exit.

In a twin-belt continuous casting machine in which a planar-moving mold casting region is defined between spaced parallel portions of upper and lower revolving casting belts and wherein said upper and lower casting belts travel partially around respective upper and lower exit pulley rolls each having an axis of rotation, apparatus for steering the revolving casting belts comprising:

• first mounting means for mounting said upper exit pulley roll providing a first effective mounting point located upstream from said upper exit pulley roll,
• said first effective mounting point and said axis of said upper exit pulley roll defining a first plane parallel with said planar moving mold casting region,
• first means for skewing said upper exit pulley roll in said first plane around said first effective mounting point for steering the upper belt laterally,
• second mounting means for mounting said lower exit pulley roll providing a second effective mounting point located upstream from said lower exit pulley roll,
• said second effective mounting point and said axis of said lower exit pulley roll defining a second plane parallel with said planar moving mold coasting region, and
• second means for skewing said lower exit pulley roll in said second plane around said second effective mounting point for steering the lower belt laterally.

The method for steering a casting belt of a twin-belt continuous metal casting machine to run centrally, said machine being arranged to cast directly from molten metal wherein the metal is introduced into a planar moving mold, said planar moving mold being defined between the surfaces of two opposed, moving endless, longitudinally tensed, flexible casting belts each revolving around at least two main pulley rolls, one of said pulley rolls being a steering pulley roll located at the exit of the moving mold, each of said pulley rolls having an axis of rotation and said pulley rolls being mounted at opposite ends of a carriage frame with their axes being in parallel relationship with the planar moving mold region, the method comprising:

• inducing longitudinal tensile force within said casting belt by exerting outward force upon the axis of at least one said pulley, said outward force being exerted in a direction away from the older axis
• revolving the longitudinally tensed belt in a course around at least two said main pulley rolls,
• exerting upon the steering pulley roll a force resulting in a minute angular skew of the axis of said steering pulley in a plane that is essentially parallel to said planar moving mold, whereby
• said belt is steered centrally on said main pulley rolls, while at the same time said steering pulley roll remains in parallel relationship to said planar moving mold cavity, and thereby
• said casting belt hugs the freezing cast product up to the point at which said belt wraps upon said steering pulley roll, thereby lengthening the planar moving mold of said twin-belt metal casting machine.

A belt-tensioning and steering system for use in a twin-belt continuous metal casting machine in which a planar moving mold region is defined between spaced parallel portions of two casting belts, said system comprising:

• a carriage frame for supporting and revolving one of said two casting belts, which carriage frame bears a pair of main pulley rolls at its opposite end, the axes of said pulley rolls defining a plane parallel to the plane of said planar moving mold region,
• a yoke upon which one of said pulley rolls is mounted, which yoke incorporates a longitudinally disposed, laterally constrained, sliding guide member mounted on said carriage frame and extending perpendicular to the axis of said one pulley roll,
• force-applying means coupled between said carriage frame and said yoke for producing an elastic angular skew of said yoke in a plane essentially parallel to that of said planar moving mold region for steering the revolving casting belt, and
• belt-tensioning means coupled between said carriage frame and said sliding guide member for sliding said member in a direction away from the pulley roll at the opposite end of the carriage frame, for tensioning the belt.