A system thermally treats rails. The system has a cooling device for spraying a cooling medium onto a rail to be treated. The cooling device defines a cooling path for receiving the rail to be treated. A conveyor moves the rail to be thermally treated through the cooling path. A vertically displacing device for displacing at least one of the cooling devices for adjusting a position of the one cooling device relative to the rail to be treated.

A section mill (10) for the rolling of steel sections is disclosed. The section mill includes a universal mill stand (12) and an edger mill stand (14) for rolling a workpiece (18) in a plurality of back-and-forth passes into a steel section having a web and one or more flanges. The section mill further includes a cooling arrangement (16) for cooling the workpiece while it undergoes rolling during one or more of the passes. The cooling arrangement includes a cooling box (20) having a spray head (21) with spray openings (22) for spraying jets of pressurized cooling liquid against the workpiece. The cooling arrangement further includes an actuator (38, 34) configured to move the cooling box relative to the stand frame (58) of the universal mill stand and/or of the edger mill stand for adjusting a distance between the spray openings and the workpiece.

A method of producing a steel material, wherein when a cooling apparatus having a plurality of cooling sections disposed side by side in a longitudinal direction of a steel material cools the steel material hot worked or cooled/reheated, the steel material is conveyed at a conveyance distance L.sub.o (m) satisfying Equation (1), in one direction along with the longitudinal direction of the steel material, in the cooling apparatus, wherein L.sub.o is defined as conveyance distance (m) of steel material, m is a natural number, and L.sub.h is defined as length (m) of cooling sections in longitudinal direction of steel material:

(m−0.20)×L.sub.h≤L.sub.o(m+0.20)×L.sub.h  (1).

A section mill (10) for the rolling of steel sections is disclosed. The section mill includes a universal mill stand (12) and an edger mill stand (14) for rolling a workpiece (18) in a plurality of back-and-forth passes into a steel section having a web and one or more flanges. The section mill further includes a cooling arrangement (16) for cooling the workpiece while it undergoes rolling during one or more of the passes. The cooling arrangement includes a cooling box (20) having a spray head (21) with spray openings (22) for spraying jets of pressurized cooling liquid against the workpiece. The cooling arrangement further includes an actuator (38, 34) configured to move the cooling box relative to the stand frame (58) of the universal mill stand and/or of the edger mill stand for adjusting a distance between the spray openings and the workpiece.

A device to cool a steel material having undergone hot rolling mills, the device including: a conveying mechanism which conveys the steel material while accelerating the steel material; a water cooling mechanism which cools the steel material while the conveying mechanism conveys the steel material; and a control unit which controls the conveying mechanism and the water cooling mechanism to cause the cooling of the steel material to satisfy Formula (1) below, wherein a water cooling time decrease rate in Formula (1) below is decided based on a length of a water cooling zone where the water cooling mechanism is provided and a time t.sub.c(0) required to cool a leading end portion of the steel material down to a target temperature,

t.sub.c(x)=t.sub.c(0).Math.xFormula (1),

where x: a conveyance-direction position in the steel material relative to the leading end portion of the steel material serving as a reference point, and t.sub.c(x): a time required to cool a portion at the position x of the steel material down to the target temperature.

Rail-manufacturing equipment that performs forced cooling on at least a head of a hot rail hot-rolled at or heated to the austenite region temperature or higher. The rail-manufacturing equipment includes a head-cooling header configured to jet a cooling medium toward the head of the rail, a head thermometer configured to measure surface temperature of the head of the rail, and a controller configured to adjust jet of the cooling medium from the head-cooling header. The controller includes a temperature-monitoring unit configured to monitor measurement results by the head thermometer during the forced cooling, and a cooling-rate controller.

A rail-manufacturing method according to the present invention performs forced cooling on at least a head of a hot rail hot-rolled at or heated to the austenite region temperature or higher. The forced cooling is performed for 10 seconds from start of the forced cooling so that the cooling rate at the head surface becomes 1 C./s or higher to 20 C./s or lower, the forced cooling is performed after a lapse of 10 seconds from the start of the forced cooling until heat generation during transformation begins in the head surface so that the cooling rate at the head surface becomes 1 C./s or higher to 5 C./s or lower, the forced cooling is performed during transformation from beginning to end of the heat generation during transformation so that the cooling rate at the head surface becomes lower than 1 C./s or the temperature-rising rate becomes 5 C./s or lower, and the forced cooling is performed after the end of the heat generation during transformation until the rail-head surface temperature becomes 450 C. or lower so that the cooling rate at the head surface becomes 1 C./s or higher to 20 C./s or lower.

Rail manufacturing method performs, on at least a head of the rail that is hot after hot-rolled at an austenite region temperature or higher or after heated to the austenite region temperature or higher, forced cooling: for 10 seconds from start of the forced cooling so that a cooling rate at a surface of the head becomes 1 C./s to 20 C./s; during a period after a lapse of 10 seconds from the start until heat generation during transformation begins at the surface so that the cooling rate becomes 1 C./s to 5 C./s; during transformation from beginning to end of the heat generation during transformation so that the cooling rate becomes lower than 1 C./s or a temperature-rising rate becomes 5 C./s or lower; and during a period after the end of the heat generation during transformation until temperature at the surface becomes 450 C. or lower so that the cooling rate becomes 1 C./s to 20 C./s.

A method of producing a steel material, wherein when a cooling apparatus having a plurality of cooling sections disposed side by side in a longitudinal direction of a steel material cools the steel material hot worked or cooled/reheated, the steel material is conveyed at a conveyance distance L.sub.o (m) satisfying Equation (1), in one direction along with the longitudinal direction of the steel material, in the cooling apparatus, wherein L.sub.o is defined as conveyance distance (m) of steel material, m is a natural number, and L.sub.h is defined as length (m) of cooling sections in longitudinal direction of steel material:

(m0.20)L.sub.hL.sub.o(m+0.20)L.sub.h(1).