The invention relates to base part of a mold for aluminothermic welding of metal rails, which base part generally has a rectangular parallelepiped and has an upper face for receiving the foot of said rails, this upper face having a hollow cavity comprising a base, two opposing longitudinal side walls, and two opposing transverse side walls. The invention is characterized in that each of said longitudinal side walls has an intermediate region surrounded by two end regions, and these end regions are located in the same plane, whereas the intermediate region has a curved profile, the well of which is directed towards the opposite side wall.

A tool assembly for performing operations in confined spaces, the tool assembly includes a telescoping pole having a proximal end and a distal end. The telescoping pole is capable of extending between a retracted position and an extended position. A working tool is connected to the distal end of the telescoping pole, and a control unit is connected to the proximal end of the telescoping pole. A flexible cable extending through the telescoping pole electrically connects the working tool to the control unit.

A programmable exothermic reaction controller includes input/output control circuitry for inputting and outputting information to/from the controller, processing circuitry including user programmable parameters, wherein the parameters are programmable using the input/output control circuitry and an output connector connectable to an ignitor cable.

A programmable exothermic reaction controller includes input/output control circuitry for inputting and outputting information to/from the controller, processing circuitry including user programmable parameters, wherein the parameters are programmable using the input/output control circuitry and an output connector connectable to an ignitor cable.

A stress-relief heat treatment method for stress-relief heat-treating a rail which is welded includes arranging at least one pair of an induction heating coil to face the rail at both sides of a welding center along the longitudinal direction of the rail while being separated from the welding center of the rail by 20 mm to 300 mm in a longitudinal direction of the rail and being an axial direction of the induction heating coil parallel to the longitudinal direction of the rail. The method further includes flowing a current to the induction heating coil arranged at one side of the welding center and to the induction heating coil arranged at the other side of the welding center being opposite to each other, and induction heating the rail to a heating temperature of 400 C. or higher and 750 C. or lower.

A stress-relief heat treatment method for stress-relief heat-treating a rail which is welded includes arranging at least one pair of an induction heating coil to face the rail at both sides of a welding center along the longitudinal direction of the rail while being separated from the welding center of the rail by 20 mm to 300 mm in a longitudinal direction of the rail and being an axial direction of the induction heating coil parallel to the longitudinal direction of the rail. The method further includes flowing a current to the induction heating coil arranged at one side of the welding center and to the induction heating coil arranged at the other side of the welding center being opposite to each other, and induction heating the rail to a heating temperature of 400 C. or higher and 750 C. or lower.

An exothermic welding cup and an exothermic welding capsule, wherein the exothermic welding cup comprises a cup, a cover and an igniter; the cup is used to accommodate welding powder, the cup has an opening, and the cover is used to cover the opening; the igniter comprises a heating portion disposed in the cup, and the heating portion has an insulating member and a heating member; and the insulating member is disposed between the heating member and the cover. The exothermic welding cup can avoid the shorting caused by the contact between the heated heating member and the cover. Also, an encapsulation ring disposed between the cover and the cup is configured to seal the welding powder within the cup so as to prevent the powder from falling out, and the encapsulation ring made of stainless steel ensures effective encapsulation of the welding powder within a certain welding time.

An exothermic welding cup and an exothermic welding capsule, wherein the exothermic welding cup comprises a cup, a cover and an igniter; the cup is used to accommodate welding powder, the cup has an opening, and the cover is used to cover the opening; the igniter comprises a heating portion disposed in the cup, and the heating portion has an insulating member and a heating member; and the insulating member is disposed between the heating member and the cover. The exothermic welding cup can avoid the shorting caused by the contact between the heated heating member and the cover. Also, an encapsulation ring disposed between the cover and the cup is configured to seal the welding powder within the cup so as to prevent the powder from falling out, and the encapsulation ring made of stainless steel ensures effective encapsulation of the welding powder within a certain welding time.

The ignition system holds a quantity of a reaction mixture in a hopper. The hopper is closed at the bottom by a movable gate. When the gate is opened, powder falls from the hopper, though a passage, and through an ignition chamber. High voltage electrodes are provided in the ignition chamber. As the powder falls through the ignition chamber, the electrodes are energized, generating an electrical arc. The arc ignites the falling powder. The ignited powder falls from the bottom of the chamber and into the reaction chamber of an exothermic mold, where the ignited powder initiates a thermite reaction that generates molten metal to form an exothermic weld.

The ignition system holds a quantity of a reaction mixture in a hopper. The hopper is closed at the bottom by a movable gate. When the gate is opened, powder falls from the hopper, though a passage, and through an ignition chamber. High voltage electrodes are provided in the ignition chamber. As the powder falls through the ignition chamber, the electrodes are energized, generating an electrical arc. The arc ignites the falling powder. The ignited powder falls from the bottom of the chamber and into the reaction chamber of an exothermic mold, where the ignited powder initiates a thermite reaction that generates molten metal to form an exothermic weld.