A piercing machine includes a plurality of skewed rolls, a plug, a mandrel bar and an outer surface cooling mechanism. The outer surface cooling mechanism is disposed around the mandrel bar at a position that is rearward of the plug, and with respect to an outer surface of a hollow shell advancing through a cooling zone which has a specific length in an axial direction of the mandrel bar and which is located rearward of the plug, as seen from an advancing direction of the hollow shell, the outer surface cooling mechanism ejects a cooling fluid toward an upper part of the outer surface, a lower part of the outer surface, a left part of the outer surface and a right part of the outer surface of the hollow shell to cool the hollow shell inside the cooling zone.

Method and control device for controlling a cooling device (10) which is set up to control the temperature of a rolling stock, preferably metal strip (B), which the cooling device (10) runs through along a conveying direction (F), the cooling device (10) preferably in front of a rolling train is arranged and the method comprises: determining a total enthalpy of the system formed by the rolling stock; Determining a measure for the formation of scale, which preferably comprises a scale factor that depends on the chemical composition and the surface temperature of the rolling stock; Calculating a temperature distribution and/or average temperature in the rolling stock on the basis of a temperature calculation model, in which the determined total enthalpy and the measure for the formation of scale are included; and setting a cooling capacity of the cooling device (10) taking into account the calculated temperature distribution and/or average temperature in the rolling stock.

Method and control device for controlling a cooling device (10) which is set up to control the temperature of a rolling stock, preferably metal strip (B), which the cooling device (10) runs through along a conveying direction (F), the cooling device (10) preferably in front of a rolling train is arranged and the method comprises: determining a total enthalpy of the system formed by the rolling stock; Determining a measure for the formation of scale, which preferably comprises a scale factor that depends on the chemical composition and the surface temperature of the rolling stock; Calculating a temperature distribution and/or average temperature in the rolling stock on the basis of a temperature calculation model, in which the determined total enthalpy and the measure for the formation of scale are included; and setting a cooling capacity of the cooling device (10) taking into account the calculated temperature distribution and/or average temperature in the rolling stock.

A method for cold rolling rolled stock (2) in a mill train (1) with multiple roll stands (3 to 7). An upper limit temperature and/or a lower limit temperature is provided for a rolled stock temperature of the rolled stock (2) for at least one rolling pass, and the rolled stock temperature is controlled and/or regulated by at least one control or regulating measure such that during the at least one rolling pass, the rolled stock temperature does not exceed the upper limit temperature specified for the rolling pass and/or the rolled stock temperature does not fall below the lower limit temperature specified for the rolling pass.

A method for cold rolling rolled stock (2) in a mill train (1) with multiple roll stands (3 to 7). An upper limit temperature and/or a lower limit temperature is provided for a rolled stock temperature of the rolled stock (2) for at least one rolling pass, and the rolled stock temperature is controlled and/or regulated by at least one control or regulating measure such that during the at least one rolling pass, the rolled stock temperature does not exceed the upper limit temperature specified for the rolling pass and/or the rolled stock temperature does not fall below the lower limit temperature specified for the rolling pass.

A cooling device for cooling a metallic item and a method for operating the cooling device. Such cooling devices having a plurality of cooling bars arranged in parallel in groups for applying a coolant to the metallic item are known in the prior art. In order to be able to set a desired distribution function of the coolant over the width of the metallic item as precisely as possible, the cooling device provides that similar application regions in at least two cooling bars within a group are each formed differently with respect to their contour and/or with respect to their surface area.

A high-strength thin-gauge checkered steel plate/strip and a manufacturing method therefor, wherein residual elements such as Sn and Cu in steel scrap are fully utilized as alloy elements in the smelting of molten steel, and the steel has selectively added micro-alloy elements such as B; during the smelting process, the alkalinity of the slag, the types of inclusion in the steel and the melting point thereof, the content of free oxygen and the content of soluble aluminum (Als) in the molten steel are controlled; and twin-roll thin-strip continuous casting is performed to cast a cast strip (11); after exiting crystallization rollers (8a, 8b), the cast strip (11) directly enters a lower sealed chamber (10) containing a non-oxidizing atmosphere, and enters an online rolling machine (13) in a sealed manner so as to undergo hot rolling, then after rolling, the strip steel is cooled by means of air atomization. The resultant steel roll can be used directly as hot-rolled checkered plate/strip, or as a finished checkered plate/strip after being cut and finished, and is widely applicable to the fields of architecture, mechanical production, automobile, bridges, transportation, ship building, etc.

A high-strength thin-gauge checkered steel plate/strip and a manufacturing method therefor, wherein residual elements such as Sn and Cu in steel scrap are fully utilized as alloy elements in the smelting of molten steel, and the steel has selectively added micro-alloy elements such as B; during the smelting process, the alkalinity of the slag, the types of inclusion in the steel and the melting point thereof, the content of free oxygen and the content of soluble aluminum (Als) in the molten steel are controlled; and twin-roll thin-strip continuous casting is performed to cast a cast strip (11); after exiting crystallization rollers (8a, 8b), the cast strip (11) directly enters a lower sealed chamber (10) containing a non-oxidizing atmosphere, and enters an online rolling machine (13) in a sealed manner so as to undergo hot rolling, then after rolling, the strip steel is cooled by means of air atomization. The resultant steel roll can be used directly as hot-rolled checkered plate/strip, or as a finished checkered plate/strip after being cut and finished, and is widely applicable to the fields of architecture, mechanical production, automobile, bridges, transportation, ship building, etc.

A tempering-free wear-resistant hot rolled strip, includes components in percentage by weight: 0.08-0.22% of C, 0.1-0.55% of Si, 0.8-1.5% of Mn, less than or equal to 0.012% of P, less than or equal to 0.005% of S, 0.01-0.055% of Als, 0.005-0.019% of Ti, and less than or equal to 0.007% of N. A method for producing the same includes: desulfurizing molten iron, smelting desulfurized molten iron, and casting into a blank; heating the casting blank; performing rough rolling; performing finish rolling; performing rapid cooling; performing coiling; and performing conventional temper rolling. According to the present disclosure, on the premise that the tensile strength of a steel plate is greater than or equal to 1100 MPa and the elongation is greater than or equal to 12%, the steel plate has a surface Brinell hardness of 330-390 and a core hardness that is 95% or above of the surface hardness.

A tempering-free wear-resistant hot rolled strip, includes components in percentage by weight: 0.08-0.22% of C, 0.1-0.55% of Si, 0.8-1.5% of Mn, less than or equal to 0.012% of P, less than or equal to 0.005% of S, 0.01-0.055% of Als, 0.005-0.019% of Ti, and less than or equal to 0.007% of N. A method for producing the same includes: desulfurizing molten iron, smelting desulfurized molten iron, and casting into a blank; heating the casting blank; performing rough rolling; performing finish rolling; performing rapid cooling; performing coiling; and performing conventional temper rolling. According to the present disclosure, on the premise that the tensile strength of a steel plate is greater than or equal to 1100 MPa and the elongation is greater than or equal to 12%, the steel plate has a surface Brinell hardness of 330-390 and a core hardness that is 95% or above of the surface hardness.