A method to determine a presence or absence of water in a cavity of a starter block having a non-horizontal surface of DC casting equipment including emitting a wave using a device containing a sensor, the wave propagating along a virtual beam path, directing the wave towards the cavity of the starter block such that the wave is reflected on a horizontal surface of the water, if water is present in the cavity, or is reflected on a non-horizontal surface of the cavity of the starter block, if no water is present in the cavity, detecting the reflected wave using the sensor, or not detecting the wave using the sensor, determining that there is water present in the cavity if the sensor detects the reflected wave, and determining that water is absent in the cavity if the sensor does not detect the wave while the sensor emits the wave.

Provided is mold flux that can prevent longitudinal cracks from forming on a surface of a slab upon continuous-casting hypo-peritectic steel, wherein CaO, SiO.sub.2, an alkali metal oxide and a fluorine compound are contained, 1.1≦(CaO).sub.h/(SiO.sub.2).sub.h≦1.9, 0.10≦(CaF.sub.2).sub.h/((CaO).sub.h+(SiO.sub.2).sub.h+(CaF.sub.2).sub.h)≦0.40 and 0≦(alkali metal fluoride).sub.h/((CaO).sub.h+(SiO.sub.2).sub.h+(alkali metal fluoride).sub.h)≦0.10 are satisfied, a solidification temperature is no less than 1300° C., and viscosity at 1450° C. is no more than 0.1 Pa.Math.s.

An aluminum alloy thick plate is formed of an aluminum alloy including Mg of 2.0 to 5.0 mass %, and has a plate thickness of 300 to 400 mm. A is 700 pieces/cm.sup.2 or less and B is 1.3 times or more as large as A, where (i) A (pieces/cm.sup.2) is a maximum value in numbers of crystallized products with a maximum length of 60 μm or more per unit area in each of positions located at a center portion in a thickness direction and at positions of 0.39 Wa to 0.48 Wa in a plate width direction; and (ii) B (pieces/cm.sup.2) is a maximum value in numbers of crystallized products with a maximum length of 60 μm or more per unit area in each of positions located at the center portion in the thickness direction and at positions of 0.12 Wa to 0.30 Wa in the plate width direction.

An aluminum alloy thick plate is formed of an aluminum alloy including Mg of 2.0 to 5.0 mass %, and has a plate thickness of 300 to 400 mm. A is 700 pieces/cm.sup.2 or less and B is 1.3 times or more as large as A, where (i) A (pieces/cm.sup.2) is a maximum value in numbers of crystallized products with a maximum length of 60 μm or more per unit area in each of positions located at a center portion in a thickness direction and at positions of 0.39 Wa to 0.48 Wa in a plate width direction; and (ii) B (pieces/cm.sup.2) is a maximum value in numbers of crystallized products with a maximum length of 60 μm or more per unit area in each of positions located at the center portion in the thickness direction and at positions of 0.12 Wa to 0.30 Wa in the plate width direction.

A method for casting longitudinal cast products including casting longitudinal cast products in a semi-continuous manner using a DC casting apparatus having a mold, wherein the mold has top and bottom openings and partially solidifies molten metal that enters into the mold via the top opening and outputs the cast product via the bottom opening, recording a thermal image of the cast product output via the bottom opening, determining at least three non-overlapping temperature ranges comprising a first, second and third, determining a peak temperature in the thermal image; comparing the peak temperature with the at least three temperature ranges; and performing operations depending on where the peak temperature falls within the at least three temperature ranges.

A method for casting longitudinal cast products including casting longitudinal cast products in a semi-continuous manner using a DC casting apparatus having a mold, wherein the mold has top and bottom openings and partially solidifies molten metal that enters into the mold via the top opening and outputs the cast product via the bottom opening, recording a thermal image of the cast product output via the bottom opening, determining at least three non-overlapping temperature ranges comprising a first, second and third, determining a peak temperature in the thermal image; comparing the peak temperature with the at least three temperature ranges; and performing operations depending on where the peak temperature falls within the at least three temperature ranges.

Provided herein is a system, apparatus, and method for continuous casting of metal, and more particularly, to a mechanism for controlling the shape of a direct chill casting mold to dynamically control a profile of an ingot cast from the mold during the casting process. Embodiments may provide an apparatus for casting material including: first and second opposing side walls; first and second end walls extending between the first and second side walls, where the first and second opposing side walls and the first and second opposing end walls form a generally rectangular shaped mold cavity. At least one of the first and second opposing side walls may include two or more contact regions, where each of the two or more contact regions may be configured to be displaced relative to a straight line along the side wall.

Provided herein is a system, apparatus, and method for continuous casting of metal, and more particularly, to a mechanism for controlling the shape of a direct chill casting mold to dynamically control a profile of an ingot cast from the mold during the casting process. Embodiments may provide an apparatus for casting material including: first and second opposing side walls; first and second end walls extending between the first and second side walls, where the first and second opposing side walls and the first and second opposing end walls form a generally rectangular shaped mold cavity. At least one of the first and second opposing side walls may include two or more contact regions, where each of the two or more contact regions may be configured to be displaced relative to a straight line along the side wall.

Described are methods of preparing compositionally gradient aluminum alloy products. The methods may include casting a composite ingot in a mold. The composite ingot may include an inner region comprising a first aluminum alloy, an outer region surrounding the inner region, and a compositionally gradient zone between the inner region and the outer region. The outer region may include a second aluminum alloy different from the first aluminum alloy. At least one alloying element of the first aluminum alloy may have a content that is decreased through the compositionally gradient zone in a direction from the inner region to the outer region. Also described are aluminum alloy composite ingots and rolled aluminum alloy products having a compositionally gradient zone.

Described are methods of preparing compositionally gradient aluminum alloy products. The methods may include casting a composite ingot in a mold. The composite ingot may include an inner region comprising a first aluminum alloy, an outer region surrounding the inner region, and a compositionally gradient zone between the inner region and the outer region. The outer region may include a second aluminum alloy different from the first aluminum alloy. At least one alloying element of the first aluminum alloy may have a content that is decreased through the compositionally gradient zone in a direction from the inner region to the outer region. Also described are aluminum alloy composite ingots and rolled aluminum alloy products having a compositionally gradient zone.