摘要:
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.
摘要:
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.
摘要:
A cooling apparatus for a hot rolled steel strip including a top surface cooling means provided above a hot rolled steel strip which is transferred with transfer rollers; and a bottom surface cooling means provided below the hot rolled steel strip, each of the top surface cooling means and the bottom surface cooling means including a protective member having at least one cooling water passage hole; at least one cooling water header opposing the hot rolled steel strip separated by the protective member; and cooling water jetting nozzles protruding from the cooling water header, wherein the tips of the cooling water jetting nozzles are disposed farther from the hot rolled steel strip than the surface, opposing the hot rolled steel strip, of the protective member.
摘要:
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.
摘要:
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.
摘要:
A cooling device and cooling method for a hot-rolled strip in which the strip can be uniformly cooled from a leading edge to a trailing edge with coolant by properly realizing a great cooling ability and a stable cooling zone.
摘要:
There are provided a cooling device and a cooling method for a hot-rolled strip in which the strip can be uniformly cooled from a leading edge to a trailing edge with coolant by properly realizing a great cooling ability and a stable cooling zone. Specifically, the following three methods are adopted. (1) Round nozzles 14 for ejecting inclined rodlike flows of coolant to a downstream side in the traveling direction of a strip 12 and round nozzles 14 for ejecting inclined rodlike flows of coolant to an upstream side in the traveling direction are arranged on an upper side of the strip 12 so as to oppose each other. (2) Round nozzles 14 for ejecting inclined rodlike flows of coolant from the upstream side of a roller table 9 toward just above the roller table 9 and round nozzles 14 for ejecting inclined rodlike flows of coolant from the downstream side of the roller table 9 toward just above the roller table 9 are arranged on the upper side of the strip 12 so as to each other. (3) Lower cooling nozzles 19 for ejecting coolant from between roller tables toward a lower surface of a strip 12 are provided on the lower side of the strip 12, and cooling nozzles 14 for ejecting inclined rodlike flows of coolant from the upstream side of a position where the coolant ejected from the lower cooling nozzles 19 collides with the strip 12 toward just above the position and cooling nozzles 14 for ejecting inclined rodlike flows from the downstream side of the position toward just above the position are arranged on the upper side of the strip 12 so as to oppose each other.
摘要:
A device and a method for cooling a hot strip capable of uniformly cooling the hot-rolled steel strip from the leading end to the trailing end thereof during cooling of the steel strip using cooling water are provided. A cooling device 10 includes a plurality of tubular nozzles 15 inclined so as to eject rod-like flows of cooling water to a steel strip 12 at an ejecting angle θ in a traveling direction of the steel strip 12 and a pinch roller 11 disposed downstream of the tubular nozzles, the steel strip 12 to be nipped between the pinch roller 11 and a table roller 8.
摘要:
A cooling apparatus for a hot rolled steel strip comprising: top surface cooling means provided above a hot rolled steel strip which is transferred with transfer rollers; and a bottom surface cooling means provided below the hot rolled steel strip, each of the top surface cooling means and the bottom surface cooling means comprising: a protective member having at least one cooling water passage hole; at least one cooling water header opposing the hot rolled steel strip separated by the protective member; and cooling water jetting nozzles protruding from the cooling water header, wherein the tips of the cooling water jetting nozzles are disposed farther from the hot rolled steel strip than the surface, opposing the hot rolled steel strip, of the protective member.
摘要:
A hot-strip cooling device for cooling a hot strip that has been subjected to finish rolling while being conveyed over a run-out table. The device includes a plurality of cooling nozzles that are disposed above a steel strip and eject rod-like flows of coolant at an ejection angle tilted toward the upstream side in a steel-strip traveling direction; and purging means that is disposed on the upstream side with respect to the cooling nozzles and purges the coolant that has been ejected from the cooling nozzles and resides on the steel strip.