A method to determine the crater end location of a cast metal product during its casting, the crater end location being the location at which the cast metal product becomes fully solidified. A continuous casting method and a continuous casting machine are also provided.

Grain size of a deliverable metal product can be improved by pre-setting recrystallization-suppressing dispersoids during casting. The outer regions of a direct chill cast embryonic ingot can undergo reheating before casting is complete. Through unique wiper placement and/or other reheating techniques, the temperature of the ingot can be permitted to reheat (e.g., up to approximately 410 C. to approximately 420 C.), allowing dispersoids to form. Stirring and/or agitation of the molten sump can facilitate formation of a deeper sump and desirably fine grain size as-cast. The formation of dispersoids during and/or immediately after casting can pin the grain boundaries at the desirably fine grain size, encouraging the same grain sizes even after a later recrystallization and/or solutionizing step.

Grain size of a deliverable metal product can be improved by pre-setting recrystallization-suppressing dispersoids during casting. The outer regions of a direct chill cast embryonic ingot can undergo reheating before casting is complete. Through unique wiper placement and/or other reheating techniques, the temperature of the ingot can be permitted to reheat (e.g., up to approximately 410 C. to approximately 420 C.), allowing dispersoids to form. Stirring and/or agitation of the molten sump can facilitate formation of a deeper sump and desirably fine grain size as-cast. The formation of dispersoids during and/or immediately after casting can pin the grain boundaries at the desirably fine grain size, encouraging the same grain sizes even after a later recrystallization and/or solutionizing step.

Secondary cooling apparatus in a machine for continuous casting of metal products, such that each metal product is cast, contained and guided along an axis of movement. The secondary cooling apparatus includes a plurality of cooling assemblies disposed in sequence one to the other along the continuous casting machine. Each assembly includes a plurality of cooling units each provided with one or more nozzles disposed along the axis of movement. The cooling units of each assembly are adjacent to each other to cover a width at least equal to the maximum width of the metal product which can be cast in the continuous casting machine.

A method to control a secondary cooling apparatus in a machine for continuous casting of metal products is provided. The secondary cooling apparatus includes a plurality of cooling units equipped with nozzles, each nozzle is provided with delivery orifices from which a refrigerant fluid is delivered, on each occasion according to the punctual cooling needs, toward a metal product.

A molten metal processing device including a molten metal containment structure for reception and transport of molten metal along a longitudinal length thereof. The device further includes a cooling unit for the containment structure including a cooling channel for passage of a liquid medium therein, and an ultrasonic probe disposed in relation to the cooling channel such that ultrasonic waves are coupled through the liquid medium in the cooling channel and through the molten metal containment structure into the molten metal.

A molten metal processing device including a molten metal containment structure for reception and transport of molten metal along a longitudinal length thereof. The device further includes a cooling unit for the containment structure including a cooling channel for passage of a liquid medium therein, and an ultrasonic probe disposed in relation to the cooling channel such that ultrasonic waves are coupled through the liquid medium in the cooling channel and through the molten metal containment structure into the molten metal.

Provided is a continuous casting method of steel that prevents a solidification completion position from being changed even when a drawing speed V of a cast slab is changed. The method includes drawing a cast slab by setting a drawing speed V0 while spraying cooling water to the cast slab at a cooling water spray amount W0 [kg/ton-cast slab]. Then, changing the drawing speed to the speed V1 while spraying cooling water to the cast slab at a cooling water spray amount W1 [kg/ton-cast slab]. The method further includes spraying cooling water to the cast slab at a cooling water spray amount Wt [kg/ton-cast slab] during a period of time t that is obtained by dividing a target length Lt by the drawing speed V0. The water spray amount Wt satisfying either formula (1): Wt<W1 under a condition of V1<V0, or formula (2): Wt>W1 under a condition of V1>V0.

A steel for machine structural use according to the present embodiment has a chemical composition which consists of, in mass %, C: 0.30 to 0.50%, Si: 0.01 to 0.80%, Mn: 0.20 to 2.00%, P: 0.030% or less, S: 0.010 to 0.100%, Pb: 0.010 to 0.100%, Al: 0.010 to 0.050%, N: 0.015% or less, O: 0.0005 to 0.0030% and Cr: more than 0.70% to 2.00%, with the balance being Fe and impurities, the chemical composition satisfying Formula (1). The total number of specific inclusions included in the steel which are any of MnS inclusions, Pb inclusions and composite inclusions containing MnS and Pb and which have an equivalent circular diameter of 5 m or more is 40 per mm.sup.2 or more.

Mn/S8.0(1)

Where, a content (mass %) of a corresponding element is substituted for each symbol of an element in Formula (1).

A strand casting installation in which a conicity of a die is set during a casting procedure by measuring temperature values along a centric measuring path running in a casting direction along an adjustably disposed die wall; measuring temperature values along a peripheral measuring path running in a casting direction along the adjustably disposed die wall, wherein the peripheral measuring path runs between the centric measuring path and a lateral periphery of the die wall, and a spacing of the peripheral measuring path from the lateral periphery of the die wall is smaller than a spacing of the centric measuring path from the other lateral periphery of the die wall; determining a centric temperature distribution curve along the centric measuring path from the temperature values measured along the centric measuring path; determining a peripheral temperature distribution curve along the peripheral measuring path from the temperature values measured along the peripheral measuring path; determining a first area under the centric temperature distribution curve, and a second area under the peripheral temperature distribution curve; determining a difference between the second area and the first area; and setting the conicity of the die taking into account the difference.