A method of removing a crack in a metallic material during a metal making process. The method including: determining the presence of a crack and its crack depth during the metal making process by a crack detecting unit utilizing inductive measurement, sending a crack detection signal and crack depth to a crack removal unit arranged on known distance from the crack detecting unit, the crack removal unit including an ejector configured to eject a carving means, and to vary the intensity of the ejected carving means, removing the detected crack by activating the ejector based on the crack detection signal with an intensity of the ejected carving means based at least on the crack depth.

A real-time monitoring method for continuous casting process and a stability analysis method for continuous casting process includes several sub-processes divided according to the process sequence of the continuous casting process. The real-time monitoring method includes: determining the current sub-process of continuous casting process according slab length data and slab speed data, performing an abnormality diagnosis on the real-time data of key parameters corresponding to the current sub-process, and generating abnormality diagnosis results corresponding to the current sub-process. The stability analysis method provides: dividing actual data of key parameters into data segments corresponding to a plurality of sub-processes, inputting the actual data of key parameters belonging to the corresponding data segments into a stability feature model, outputting a stability feature index, performing abnormality diagnosis on the stability feature index, and generating an abnormality diagnosis result corresponding to the corresponding sub-process based on the output of the abnormality diagnosis.

A real-time monitoring method for continuous casting process and a stability analysis method for continuous casting process includes several sub-processes divided according to the process sequence of the continuous casting process. The real-time monitoring method includes: determining the current sub-process of continuous casting process according slab length data and slab speed data, performing an abnormality diagnosis on the real-time data of key parameters corresponding to the current sub-process, and generating abnormality diagnosis results corresponding to the current sub-process. The stability analysis method provides: dividing actual data of key parameters into data segments corresponding to a plurality of sub-processes, inputting the actual data of key parameters belonging to the corresponding data segments into a stability feature model, outputting a stability feature index, performing abnormality diagnosis on the stability feature index, and generating an abnormality diagnosis result corresponding to the corresponding sub-process based on the output of the abnormality diagnosis.

Provided are lean duplex stainless steel having a dual-phase structure of an austenite phase and a ferrite phase, and a method for producing the lean duplex stainless steel. The lean duplex stainless steel, as a ferrite-austenite stainless steel, has the preferred stacking fault energy (SFE) value of the austenite phase, expressed by the formula 2 below, of 19-37 and critical strain value range, within which the strain-induced martensite phases occurs, of 0.1−0.25. Formula 2: SFE=25.7+1.59×Ni/[K(Ni)−K(Ni)×V(γ)+V(γ)]+0.795×Cu/[K(Cu)−K(Cu)×V(γ)+V(γ)]−0.85×Cr/[K(Cr)−K(Cr)×V(γ)+V(γ)]+0.001×(Cr/[K(Cr)−K(Cr)×V(γ)+V(γ)]).sup.2+38.2×(N/[K(N)−K(N)×V(γ)+V(γ)]).sup.0.5−2.8×Si/[K(Si)−K(Si)×V(γ)+V(γ)]−1.34×Mn/[K(Mn)−K(Mn)×V(γ)+V(γ)]+0.06×(Mn/[K(Mn)−K(Mn)×V(γ)+V(γ)]).sup.2. Ni, Cu, Cr, N, Si and Mn indicate the overall content (wt. %) of the respective constituent element, and K(x) is the distribution index of respective constituent element (x) and is expressed by the formula 3 below, and V(γ) is the component ratio of austenite (in the 0.45-0.75 range). Formula 3: K(x)=[amount of element x in ferrite phase]/[amount of element x in austenite phase]

An apparatus for the automatic startup of a continuous casting line, including a vessel which is connected to a tip by means of a gate, the tip feeding a casting housing. The apparatus includes a laser device which measures the level of the metal within the vessel, a level control device, which adjusts the introduction of liquid metal into the vessel, a gate actuator to control the gate for providing a barrier between the vessel and the tip, a transducer for the temperature of the metal inside the vessel, and a PLC which receives data from the temperature transducer and from the laser device to control the level control device and the gate actuator, so as to adjust the vessel metal level to ensure a correct and continuous flow of metal toward the casting cylinders, in order to avoid poor diffusion of the metal inside the tip.

An apparatus for the automatic startup of a continuous casting line, including a vessel which is connected to a tip by means of a gate, the tip feeding a casting housing. The apparatus includes a laser device which measures the level of the metal within the vessel, a level control device, which adjusts the introduction of liquid metal into the vessel, a gate actuator to control the gate for providing a barrier between the vessel and the tip, a transducer for the temperature of the metal inside the vessel, and a PLC which receives data from the temperature transducer and from the laser device to control the level control device and the gate actuator, so as to adjust the vessel metal level to ensure a correct and continuous flow of metal toward the casting cylinders, in order to avoid poor diffusion of the metal inside the tip.

A method and apparatus for casting thin strip including assembling a pair of counter-rotating casting rolls forming a gap between the casting surfaces of the rolls at a nip between the rolls through which metal strip can be casted; assembling side dams adjacent end portions of the rolls to permit a casting pool of molten metal to be formed on the casting surfaces; counter-rotating the rolls such that the casting surfaces each travel inwardly toward the nip to form metal shells on the surfaces of the rolls and deliver a cast strip downwardly from the gap between the rolls with a mushy internal portion; and providing a drive mechanism to oscillate the gap amplitude between the casting rolls between ±5 and ±50 microns at a frequency between 1 and 7 hertz to vary thickness of the mushy in the cast strip and reduce chatter during casting.

Provided is a slab warpage detection apparatus detecting warpage of a slab drawn from a mold in continuous casting equipment. The slab warpage detection apparatus includes a pair of pressing roils that pinches the slab on a rear side of a roll segment, supporting the slab drawn from the mold, in a slab drawing direction, a movement unit that supports the pair of pressing rolls to be movable in a thickness direction of the slab, and a position detecting unit that detects positions of the pressing rolls in the thickness direction of the slab.

Provided is a slab warpage detection apparatus detecting warpage of a slab drawn from a mold in continuous casting equipment. The slab warpage detection apparatus includes a pair of pressing roils that pinches the slab on a rear side of a roll segment, supporting the slab drawn from the mold, in a slab drawing direction, a movement unit that supports the pair of pressing rolls to be movable in a thickness direction of the slab, and a position detecting unit that detects positions of the pressing rolls in the thickness direction of the slab.

In this cast strip manufacturing method, in a first step, one end side and another end side in a rotation axis direction of a pair of cooling drums are pressed with a first pressure in a direction in which the cooling drums come close to each other, in a second step, the one end side and the another end side in the rotation axis direction of the cooling drums are pressed with a second pressure, which is higher than the first pressure, in the direction in which the cooling drums come close to each other, and in a third step, pressure control is performed so that a total value of reaction forces on the one end side and the another end side in the rotation axis direction of the cooling drums is set to a predetermined value, and rotation axes of the cooling drums are held in parallel.