A rolling mill has a rolling stand (1) in which a flat rolled product (2) composed of metal is rolled. A sensor device (6), which detects at least one measured variable (M) characteristic of a material property of the flat rolled product (2), is arranged upstream and/or downstream of the rolling stand (1). The material property can be, in particular, an electromagnetic property or a mechanical property of the rolled product (2). The sensor device (6) transfers the detected measured variable (M) to a control device (9) for the rolling mill. Taking into account the measured variable (M), the control device (9) determines a control value (A) for the rolling stand (1). The control of the rolling stand (1) influences the material property of the flat rolled product (2). The control value (A) is a ratio of the peripheral speeds (vO, vU) at which the upper and the lower working rolls (3, 4) of the rolling stand (1) rotate.

A hot-rolled steel sheet includes a specific chemical composition, and includes a microstructure represented by, in vol %: retained austenite: 2% to 30%; ferrite: 20% to 85%; bainite: 10% to 60%; pearlite: 5% or less; and martensite: 10% or less. A proportion of grains having an intragranular misorientation of 5° to 14° in all grains is 5% to 50% by area ratio, the grain being defined as an area which is surrounded by a boundary having a misorientation of 15° or more and has a circle-equivalent diameter of 0.3 μm or more.

A framework cooler (20) for cooling a steel strip (50), installed in a roller framework (11), in place of the work rolls (5) and their associated installation pieces (5a and 5b). The framework cooler (20) is sized to be installed into the roller framework (11) through the operator-side roller stands (1) of the roller framework (11). The cooler (20) includes a lower (21b) and an upper water tank (21a), each having a connection (22) for a coolant, and includes a plurality of cooling nozzles (23), or cooling tubes (23a) arranged in the depth direction (T) of the framework cooler (20) or at least one cooling slot (24) extending in the depth direction (T). The bottom and top sides of the steel strip (50) may be cooled.

Provided is a cooling device, where a hot-finish-rolling mill includes a plurality of nozzles which spray cooling water toward one of or both of upper and lower surfaces of a hot-rolled steel sheet just after rolled by rolling stands, the nozzles are provided on the inside of the upper and lower guides or adjoining to the guides on a downstream side, and a nozzle spray distance changes depending on a position of the nozzle in a rolling direction, wherein a spray angle of the nozzle at a position whose nozzle spray distance is the largest is smaller than a spray angle of the nozzle at a position whose nozzle spray distance is the smallest, and the spray angle of the nozzle becomes the same or smaller as the nozzle spray distance becomes large.

Disclosed is a method of emulsion concentration optimization for a cold continuous rolling mill set for achieving vibration suppression, the method comprising: defining the process parameters involved in the process of emulsion concentration optimization; setting an initial set value of an emulsion concentration comprehensive optimization target function for a cold continuous rolling mill set for achieving vibration suppression; calculating a bite angle of each stand; calculating a vibration determination index reference value of each stand; setting the emulsion concentration of each stand; calculating the outlet temperature of a strip steel of each stand; calculating the dynamic viscosity of an emulsion in a roll gap of each stand; calculating the oil film thickness in the roll gap of each stand; calculating the emulsion concentration comprehensive optimization target function; determining whether the inequation F(X)<F.sub.0 is established; determining whether the concentration of the emulsion exceeds a feasible region range, and outputting the optimal emulsion concentration set value.

The present invention discloses a heating system for drill steel pipe billet, comprising a feedback device, a propulsion device, a positioning device, a heating device, a temperature measuring device and a conveying device. The distance d.sub.1 and d.sub.2 of three flamethrowers are controlled through the feedback device. The heating temperature of the flamethrowers is controlled by the oxygen distribution box and the gas distribution box. On the other hand, the present invention also provides a heating method for drill steel pipe billet, which adopts the rolling forming method of gradient flame heating, which realizes the control of the density of the rolled pieces, avoiding the internal defects of the drill steel caused by the same deformation of the traditional pipe billet after uniform heating, improving the quality of the drill steel, and prolonging the service life of the drill steel. The radial temperature of the drill steel pipe billet is accurately controlled through the feedback device. Flame heating with low cost is adopted. For drill steel pipe billets of different dimensions, only a set of flamethrowers corresponding to the dimensions needs to be designed, and other devices are universal components, which do not need to be replaced.

Methods for producing a coiled strip of metal matrix composite (MMC) material are disclosed. The methods include a combination of hot rolling and warm rolling processes that reduce the thickness of the input material and increase its ductility. The resulting MMC strip can be coiled, which is useful for high volume coil-to-coil applications.

A rolling mill has a rolling stand (1) in which a flat rolled product (2) composed of metal is rolled. A sensor device (6), which detects at least one measured variable (M) characteristic of a material property of the flat rolled product (2), is arranged upstream and/or downstream of the rolling stand (1). The material property can be, in particular, an electromagnetic property or a mechanical property of the rolled product (2). The sensor device (6) transfers the detected measured variable (M) to a control device (9) for the rolling mill. Taking into account the measured variable (M), the control device (9) determines a control value (A) for the rolling stand (1). The control of the rolling stand (1) influences the material property of the flat rolled product (2). The control value (A) is a ratio of the peripheral speeds (vO, vU) at which the upper and the lower working rolls (3, 4) of the rolling stand (1) rotate.

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 hot and cold composite formed square and rectangular steel tube and a production method for the same are provided. The radius of an outer corner of the square and rectangular steel tube meets the following conditions: when t is less than or equal to 6 mm, R is greater than 0 and less than 2.0 t; when t is greater than 6 mm and less than or equal to 10 mm, R is greater than 0 and less than 2.5 t; when t is greater than 10 mm, R is greater than 0 and less than 3.0 t, wherein t is the wall thickness of a straight tube part of the square and rectangular steel tube; R is the radius of each of the outer corners of the four corners of the square and rectangular steel tube; and the wall thickness of each corner of the square and rectangular steel tube is between 1.0 t and 1.8 t.