This hot-rolled steel sheet has a predetermined chemical composition, in which a microstructure contains, by area %, bainite: 80.0% or more, ferrite: 10.0% or less, and a remainder in the microstructure: 10.0% or less, a total density of a length L.sub.7 of a grain boundary having a crystal orientation difference of 7° and a length L.sub.68 of a grain boundary having a crystal orientation difference of 68° about a <110> direction in the bainite is 0.35 to 0.60 μm/μm.sup.2, and a tensile strength is 780 MPa or more.

This hot-rolled steel sheet has a predetermined chemical composition, in which a microstructure contains, by area %, bainite: 80.0% or more, ferrite: 10.0% or less, and a remainder in the microstructure: 10.0% or less, a total density of a length L.sub.7 of a grain boundary having a crystal orientation difference of 7° and a length L.sub.68 of a grain boundary having a crystal orientation difference of 68° about a <110> direction in the bainite is 0.35 to 0.60 μm/μm.sup.2, and a tensile strength is 780 MPa or more.

A rolling mill includes a plurality of stands configured to roll a material to be rolled, wherein at least one stand, among the stands, includes: at least one pair of rolling mill rolls; a roll chock that rotatably support the rolling mill rolls; and a roll chock liner that includes a first liner plate mounted on the roll chock, a second liner plate stacked on the first liner plate in a rolling direction, and an elastic member interposed between the first liner plate and the second liner plate.

A hot rolled steel sheet is provided, which is excellent in collision characteristics, excellent in anisotropy of toughness, and high in strength. The hot rolled steel sheet is characterized by containing, by mass %, C: 0.10% to 0.50%, Si: 0.10% to 3.00%, Mn: 0.5% to 3.0%, P: 0.100% or less, S: 0.010% or less, Al: 1.00% or less, N: 0.010% or less and a balance of Fe and impurities, wherein a metal structure at position of ¼ thickness from surface in L-cross-section of the steel sheet comprises prior austenite grains of average value of aspect ratios of 2.0 or less, average grain size of 0.1 μm to 3.0 μm, and coefficient of variation of a standard deviation of grain size distribution/average grain size of 0.40 or more, and a texture with X-ray diffraction intensity ratio of {001}<110>orientation for random samples of 2.0 or more, and the steel sheet has tensile strength of 1180 MPa or more.

A hot rolled steel sheet is provided, which is excellent in collision characteristics, excellent in anisotropy of toughness, and high in strength. The hot rolled steel sheet is characterized by containing, by mass %, C: 0.10% to 0.50%, Si: 0.10% to 3.00%, Mn: 0.5% to 3.0%, P: 0.100% or less, S: 0.010% or less, Al: 1.00% or less, N: 0.010% or less and a balance of Fe and impurities, wherein a metal structure at position of ¼ thickness from surface in L-cross-section of the steel sheet comprises prior austenite grains of average value of aspect ratios of 2.0 or less, average grain size of 0.1 μm to 3.0 μm, and coefficient of variation of a standard deviation of grain size distribution/average grain size of 0.40 or more, and a texture with X-ray diffraction intensity ratio of {001}<110>orientation for random samples of 2.0 or more, and the steel sheet has tensile strength of 1180 MPa or more.

An induction motor overheat monitoring method and device detects overheating of an induction motor from a detection value of a current sensor. A resistance calculation relationship data indicating a relationship between a resistance and a feature amount at the time of starting of the induction motor and a determination reference value for determining overheating are stored in advance. At each starting, a current of the induction motor is detected, a signal regarding a phase angle difference is calculated, and a feature amount of the motor is calculated from the signal regarding the phase angle difference. Further, a resistance of the induction motor is calculated by using the feature amount of the motor and the resistance calculation reference data stored in advance. Then, a temperature of the induction motor is calculated from the resistance of the induction motor, and it is determined if the motor is overheated.

An induction motor overheat monitoring method and device detects overheating of an induction motor from a detection value of a current sensor. A resistance calculation relationship data indicating a relationship between a resistance and a feature amount at the time of starting of the induction motor and a determination reference value for determining overheating are stored in advance. At each starting, a current of the induction motor is detected, a signal regarding a phase angle difference is calculated, and a feature amount of the motor is calculated from the signal regarding the phase angle difference. Further, a resistance of the induction motor is calculated by using the feature amount of the motor and the resistance calculation reference data stored in advance. Then, a temperature of the induction motor is calculated from the resistance of the induction motor, and it is determined if the motor is overheated.

A method for producing a patterned stainless steel sheet with improved visual characteristics in the wavelength area of visible light including providing a deformed stainless steel sheet; performing a heat treatment on the deformed stainless steel sheet, wherein the heat treatment is conducted at a temperature of 900-1200° C.; performing a mechanical treatment on at least one surface of the heat treated stainless steel sheet; transferring the mechanically treated stainless steel sheet to a patterning process, wherein, in the patterning process, at least one side of the mechanically treated stainless steel sheet is patterned using a patterning roll having a surface with an emboss depth of up to 100 micrometers to provide a patterned stainless steel sheet; and performing a heat treatment on the patterned stainless steel sheet, wherein the heat treatment is conducted at a temperature range of 900-1200° C., wherein the mechanical treatment is carried out by blasting.

A method for producing a patterned stainless steel sheet with improved visual characteristics in the wavelength area of visible light including providing a deformed stainless steel sheet; performing a heat treatment on the deformed stainless steel sheet, wherein the heat treatment is conducted at a temperature of 900-1200° C.; performing a mechanical treatment on at least one surface of the heat treated stainless steel sheet; transferring the mechanically treated stainless steel sheet to a patterning process, wherein, in the patterning process, at least one side of the mechanically treated stainless steel sheet is patterned using a patterning roll having a surface with an emboss depth of up to 100 micrometers to provide a patterned stainless steel sheet; and performing a heat treatment on the patterned stainless steel sheet, wherein the heat treatment is conducted at a temperature range of 900-1200° C., wherein the mechanical treatment is carried out by blasting.

A production specification determination method, a production method, and a production specification determination apparatus that can increase robustness against disturbances during production of a metal material are provided. Included are the steps of acquiring at least one piece of performance data established after a predetermined process during production of a metal material, performing back analysis based on the at least one piece of performance data and a prediction model that relates production specifications and material characteristics, and searching for production specifications for after the predetermined process such that an estimated value for the material characteristics asymptotically approaches a desired value.