Abstract: A method for cooling a hot rolled steel strip including transferring a hot rolled steel strip while ejecting cooling water from a cooling means at a specified ejecting condition; pinching a top end of the hot rolled steel strip by a pinching roll, at the inlet of the cooling means and/or just behind the cooling means and/or at a position on the way of the cooling means; and releasing the hot rolled steel strip sequentially from a pinch roll arranged at an upstream side, concurrently with the arrival of a top end of the steel strip to a tension adding means arranged at a downstream side.

Abstract: An apparatus for cooling a hot rolled steel strip including a transfer means comprising transfer rolls to feed a steel strip which has been hot rolled by a finishing mill; a cooling means for cooling the steel strip; and accompanying rolls arranged with a clearance over the thickness of the steel strip at a position where the accompanying rolls face the transfer rolls through the steel strip to be transferred. The accompanying rolls rotate at nearly an equal peripheral speed as the transfer rolls or at a peripheral speed greater than the transfer speed of the steel strip.

Abstract: An apparatus for cooling a hot rolled steel strip comprising a transfer means arranged behind a final finishing mill, the transfer means comprising a plurality of transfer rolls for transferring the steel strip; at least one upper surface cooling means arranged at an upper surface side of the transfer means for cooling the steel strip by ejecting cooling water to an upper surface of the steel strip, the upper surface cooling means being capable of moving freely up and down and having a water breaking means at least at an outlet side of the cooling apparatus and at a position corresponding to the transfer rolls; and at least one lower surface cooling means arranged at a lower surface side of the transfer means relative to the upper surface cooling means and the steel strip to be transferred, for cooling the hot strip by ejecting cooling water at a lower surface of the steel strip.

Abstract: The present invention relates to a cooling apparatus for hot rolled steel strip comprising: top surface cooling means provided above a hot rolled steel strip transferred with transfer rollers after hot rolling to cool the top surface of the hot rolled steel strip; and bottom surface cooling means provided below the hot rolled steel strip to cool the bottom surface of the hot rolled steel strip, each of the top surface cooling means and the bottom surface cooling means comprising: a protective member disposed close to the surface of the hot rolled steel strip, having at least one cooling water passage hole; at least one cooling water header opposing the hot rolled steel strip separated.

Abstract: The present invention relates to a method for cooling a steel plate comprising the steps of: forming a water pool with jets of cooling water being injected to impinge on one another by using one slit nozzle and a plurality of induced laminar flow nozzles, the slit nozzle being provided in a position on an upper surface side of the steel plate, and the induced laminar flow nozzles being provided in a position on a lower surface side of the steel plate along a transfer direction and a direction perpendicular to the transfer direction; and passing the steel plate into the water pool, wherein when a top portion of the steel plate passes over the induced laminar flow nozzles located at least on the side of highest upstream, a volume of the cooling water to be injected from each of the induced laminar flow nozzles is reduced.

Abstract: An apparatus for cooling a hot rolled steel strip comprising a transfer means arranged behind a final finishing mill, the transfer means comprising a plurality of transfer rolls for transferring the steel strip; at least one upper surface cooling means arranged at an upper surface side of the transfer means for cooling the steel strip by ejecting cooling water to an upper surface of the steel strip, the upper surface cooling means being capable of moving freely up and down and having a water breaking means at least at an outlet side of the cooling apparatus and at a position corresponding to the transfer rolls; and at least one lower surface cooling means arranged at a lower surface side of the transfer means relative to the upper surface cooling means and the steel strip to be transferred, for cooling the hot strip by ejecting cooling water at a lower surface of the steel strip.

Abstract: A lower surface cooling box 12 is arranged between transfer rolls 11 on a runout table 3 and an upper cooling box 14 moving freely is arranged at a position corresponding to the cooling box 12 to eject cooling water to the steel strip symmetrically in the vertical direction. The steel strip passes the center of converge of cooling water from upper and lower surfaces of the steel strip. A water breaking roll 16 is provided elevating freely at least at the outlet side rotating at the same peripheral speed as the transfer rolls and is rotated to lower concurrently with passing of the steel strip top at the cooling apparatus. The upper cooling box is also lowered concurrently to cool the steel strip.

Abstract: A lower surface cooling box 12 is arranged between transfer rolls 11 on a runout table 3 and an upper cooling box 14 moving freely is arranged at a position corresponding to the cooling box 12 to eject cooling water to the steel strip symmetrically in the vertical direction. The steel strip passes the center of convergence of cooling water from upper and lower surfaces of the steel strip. A water breaking roll 16 is provided elevating freely at least at the outlet side rotating at the same peripheral speed as the transfer rolls and is rotated to lower concurrently with passing of the steel strip top at the cooling apparatus. The upper cooling box is also lowered concurrently to cool the steel strip.

Abstract: An apparatus for making a silicon single crystal large in diameter dependently on the Czochralski process, wherein appropriate openings (11) are provided on the warmth keeping over (10) so as to prevent an undesirable influence caused by atmospheric gas. The major elements of the apparatus are that the sum of areas of the openings (11) is larger than the area of gap (18) formed between the lower end of the warmth keeping cover (10) and the level of silicon solution, and that the warmth keeping cover and the heat insulating member (12) are composed of sheet metal.

Abstract: A crucible including a cylindrical partition member arranged concentrically therein for use in a silicon single crystal growing apparatus. The bottom of the crucible located on the inner side of the partition member has a thickness which is not less than 1.3 times and not greater than 4 times the thickness of the partition member and it also has a porosity which is between 0 and 0.2% in its inner layer and between 0.2 and 15% in its outer layer as compared with the porosity of the partition member which is 0.2% or less. By virtue of the foregoing, a D.F. ratio (ratio of dislocation free) of 80% or over can be expected.

Abstract: A method for manufacturing a high strength rail with good toughness, comprises cooling a rail to Ar.sub.3 transformation point or less after hot rolling; heating said cooled rail at a temperature of an austenite temperature zone ranging from Ac.sub.3 transformation point to 950.degree. C.; and cooling the heated rail. The chemical composition of the rail consists of 0.50 to 0.85 wt. % C, 0.50 to 1.50 wt. % Mn, 0.035 wt. % S or less, 0.10 to 1.00 wt. % Si, 0.035 wt. % P or less, 0.050 wt. % Al or less and the balance of Fe and inevitable impurities.

Abstract: A method for heat-treating a steel rail head, which comprises: heating a steel rail head to the austenization temperature; then, cooling the rail head by means of a hot water jet until a surface temperature of the rail head decreases to a temperature not below 420.degree. C.; and then cooling the rail head by means of an air jet at least to the pearlite transformation temperature, thereby transforming the structure of a surface portion of the rail head into a uniform and fine pearlite structure. The above-described method includes a method in which the rail head is previously cooled by means of a water spray until the surface temperature of the rail head decreases to a temperature not below 530.degree. C. prior to the cooling of the rail head by means of the above-mentioned hot water jet.