A method of cooling control for a steel plate, a cooling control device, and a method of manufacturing a steel plate, which adjust an upper/lower water ratio and prevent C-warping during cooling. The method of cooling control includes: determining an upper/lower water ratio of a steel plate being cooled wherein at least one of a C-warping amount and a curvature is within a target permissible range, based on a past operating condition, a past upper/lower water ratio when cooling under the past operating condition has been implemented, and at least one of a past C-warping amount and a past curvature measured by a shape measuring meter at an outgoing side of a cooling zone when the cooling under the past operating condition is implemented; and adjusting an amount of cooling water to be blown onto the steel plate to reach the upper/lower water ratio.

A method of cooling control for a steel plate, a cooling control device, and a method of manufacturing a steel plate, which adjust an upper/lower water ratio and prevent C-warping during cooling. The method of cooling control includes: determining an upper/lower water ratio of a steel plate being cooled wherein at least one of a C-warping amount and a curvature is within a target permissible range, based on a past operating condition, a past upper/lower water ratio when cooling under the past operating condition has been implemented, and at least one of a past C-warping amount and a past curvature measured by a shape measuring meter at an outgoing side of a cooling zone when the cooling under the past operating condition is implemented; and adjusting an amount of cooling water to be blown onto the steel plate to reach the upper/lower water ratio.

One or more hollow billets are loaded onto an elongate mandrel bar for extrusion. The billets are transported along the mandrel bar to a rotating die. The billets are transported through fluid clamps, which engage the mandrel bar and provide cooling fluid to the mandrel bar tip, and through mandrel grips, which engage the mandrel bar and prevent the mandrel bar from rotating. One or more press-rams advance the billets through a centering insert and into the rotating die. A quench assembly is provided at an extrusion end of the extrusion press to quench the extruded material. A programmable logic controller may be provided to control, at least in part, operations of the extrusion press system.

One or more hollow billets are loaded onto an elongate mandrel bar for extrusion. The billets are transported along the mandrel bar to a rotating die. The billets are transported through fluid clamps, which engage the mandrel bar and provide cooling fluid to the mandrel bar tip, and through mandrel grips, which engage the mandrel bar and prevent the mandrel bar from rotating. One or more press-rams advance the billets through a centering insert and into the rotating die. A quench assembly is provided at an extrusion end of the extrusion press to quench the extruded material. A programmable logic controller may be provided to control, at least in part, operations of the extrusion press system.

A process for preparing a multi-thickness welded steel vehicle rail, the process comprises the steps of: (a) forming a first tube having a first outer diameter, an inner diameter and a first wall thickness; (b) forming a second tube having the first outer diameter, a second inner diameter and a second wall thickness different than the first wall thickness; (c) swaging a first end of the first tube to a second outer diameter less than the second inner diameter of the second tube; (d) inserting the swaged first end of the first tube into an end of the second tube to form a joint; (e) welding the first tube and the second tube together to form a weld at the joint to form a tube blank with a heat affected zone of lower metal strength in the area of the weld; (f) preheating the tube blank to create a common crystalline microstructure along a length of the tube blank; (g) introducing the tube blank into a blow molding tool having inner molding walls; (h) molding the tube blank at an elevated temperature by expanding the tube blank against the inner molding walls of the molding tool by injecting a pressurized medium into an interior cavity of the tube blank; and (i) quenching the tube blank by replacing the pressurized medium with a cooling medium through the molding tool and the tube blank to achieve a rapid cooling effect on the tube blank and to create a completed vehicle rail with essentially uniform material strength across the weld. A completed vehicle rail has an overlapped welded structure and uniform microcrystalline structure along the length of the rail.

A forming apparatus that forms a metal pipe material includes an electrode that holds the metal pipe material and supplies electric power to the metal pipe material to heat the metal pipe material, a forming die that quenches and forms the expanded metal pipe, and a member that suppresses quenching, in which a region where quenching is not performed in the metal pipe is adjusted by adjusting a length of the member.

An oil-immersion quenching cooling precursor and an oil-immersion quenching cooling method includes an axle-type workpiece or a workpiece that has sections in an axle form. Several separation rings are arranged on the workpiece in the axial direction to separate the axle-type workpiece or the workpiece that has sections in an axle form into a plurality of sections before oil-immersion quenching cooling. In the method, there is a cutting procedure before a quenching cooling procedure. Several separation rings distributed in the axial direction are reserved outside a dimension required for the workpiece. sections before oil-immersion quenching cooling. In the method, there is a cutting procedure before a quenching cooling procedure. Several separation rings distributed in the axial direction are reserved outside a dimension required for the workpiece.

An oil-immersion quenching cooling precursor and an oil-immersion quenching cooling method includes an axle-type workpiece or a workpiece that has sections in an axle form. Several separation rings are arranged on the workpiece in the axial direction to separate the axle-type workpiece or the workpiece that has sections in an axle form into a plurality of sections before oil-immersion quenching cooling. In the method, there is a cutting procedure before a quenching cooling procedure. Several separation rings distributed in the axial direction are reserved outside a dimension required for the workpiece. sections before oil-immersion quenching cooling. In the method, there is a cutting procedure before a quenching cooling procedure. Several separation rings distributed in the axial direction are reserved outside a dimension required for the workpiece.

Provided are a dual-frequency power-supply apparatus, a high-frequency heating apparatus, and a high-frequency quenching apparatus having a high durability.

A dual-frequency power-supply apparatus 1 includes a power supply 10 that alternately outputs a low-frequency current and a high-frequency current. The power supply 10 has an inverter 30 that converts a direct current into the low-frequency current and the high-frequency current and a controller 40 that controls the inverter 30. The controller 40 repeats, in this order, a first output period T11 in which the low-frequency current is output, a first intermission T12 in which output is stopped, a second output period T13 in which the high-frequency current is output, and a second intermission T14 in which output is stopped. The controller 40 sets the length of the first intermission T12 longer than a time Ta until the polarity of the output voltage of the power supply 10 is reversed fourthly after transition from the first output period T11 to the first intermission T12.

Provided are a dual-frequency power-supply apparatus, a high-frequency heating apparatus, and a high-frequency quenching apparatus having a high durability.

A dual-frequency power-supply apparatus 1 includes a power supply 10 that alternately outputs a low-frequency current and a high-frequency current. The power supply 10 has an inverter 30 that converts a direct current into the low-frequency current and the high-frequency current and a controller 40 that controls the inverter 30. The controller 40 repeats, in this order, a first output period T11 in which the low-frequency current is output, a first intermission T12 in which output is stopped, a second output period T13 in which the high-frequency current is output, and a second intermission T14 in which output is stopped. The controller 40 sets the length of the first intermission T12 longer than a time Ta until the polarity of the output voltage of the power supply 10 is reversed fourthly after transition from the first output period T11 to the first intermission T12.