ASSEMBLY AND WELDING UNIT FOR LONGITUDINALLY WELDED PIPES

Abstract

A longitudinal welded pipe assembly and welding mill contains a trestle, on which a welding bridge configured to move is mounted, such bridge carrying welding equipment with the first welding head designed for welding on the outside of the pipe blank. A pipe blank rotation system and assembly mandrels, each containing a blank pipe longitudinal edge clamping mechanism, are installed in the trestle leg span. The mill is fitted with a cantilever crossbar mounted in the supporting assembly, with the second welding head designed for inside welding, the clamping mechanism made as hydraulic stops. The pipe blank rotation system is a welding trolley configured to move over guides and having rotary rollers designed for positioning a pipe blank in the welding position, and supporting rotary rollers located near the assembly mandrels and configured to diverge crosswise with respect to the guides to enable movement of the welding trolley into the assembly mandrel area and move in reverse up to the stop to the pipe blank surface. Technical result: expansion of the technological capabilities of existing mills by integrating equipment enabling to weld from inside and outside of the pipe blank in various sequence using various technologies and observing the geometrical accuracy of bringing together the blank edges for pipes of various diameter, in particular, for large diameter pipes.

Claims

1. A longitudinal pipe assembly and welding mill containing a trestle with guides, on which a welding bridge configured to move is mounted, such bridge carrying welding equipment with the first welding head designed for welding on the outside of the pipe blank; a pipe blank rotation system and assembly mandrels are installed in the trestle leg span, each containing a blank pipe longitudinal edge clamping mechanism, wherein this mill is fitted out with a cantilever crossbar mounted in the supporting assembly, with the second welding head designed for inside welding, the clamping mechanism is made as hydraulic stops; the pipe blank rotation system is a welding trolley configured to move over guides and having rotary rollers, and supporting rotary rollers located near the assembly mandrels and configured to diverge crosswise with respect to the guides to enable movement of the welding trolley into the assembly mandrel area and to move in reverse up to the stop to the pipe blank surface; the rotary rollers are designed for positioning a pipe blank in the welding position.

2. The mill of claim 1, wherein it contains a control system, including a control unit designed for input of signals and output of control signals to the correctors of the first and second welding heads enabling to guide the corresponding welding head to the butt-joint of the pipe blank edges; in addition, a means of displaying data on the position of the first and second welding heads and two triangulation sensorsconnected to the control unit inputsdirecting at the butt-joint of the pipe blank edges, each of which is installed on the first and second welding heads, respectively.

3. The mill of claim 1, wherein it contains a control system, including a control unit, triangulation sensors of the first and second groups installed on the assembly mandrels, a data display; the control unit is designed for input of signals and output of control signals to hydraulic stops of the assembly mandrels, the sensors of the two groups are connected to the corresponding control unit inputs, the first group sensors are designed for detecting the pipe blank profile in the cross-section located in the area between the assembly mandrels, the second group sensors are designed for detecting the profile of the butt-joint of the pipe blank edges, and the display is designed to display data on the pipe blank cross-section in the area of each assembly mandrel and in the area of the pipe blank edges butt-joint.

4. The mill of claim 1, wherein the first or the second welding head is a laser welding head for using laser welding technologies, the mill is fitted out with a protection shelter.

Description

[0030] To explain the construction of the longitudinal pipe assembly and welding mill, an example of its embodiment with a reference to drawings is provided.

[0031] FIG. 1 shows a general view of the mill;

[0032] FIG. 2 shows its transverse section.

[0033] The large diameter longitudinal pipe assembly and welding mill contains trestle 1 with rail guides 2, on which movable welding bridge 3 is installed; the bridge carries welding equipment with first welding head 4.

[0034] Depending on the welding technology, the first head has various designs and can perform welding in the protective gas atmosphere, multiarc welding under a flux layer, laser, and hybrid laser arc welding. To apply several outside welds, the welding bridge is repeatedly passed along the pipe to apply weld under another technology, or the welds are concurrently applied by combining heads for various welding processes into one welding process.

[0035] In the span of trestle 1, assembly mandrels 5 are installed with radially located hydraulic stops 6 for pipe blank compression; in addition, rail track 7 is installed with welding trolley 8 configured to move along this rail track, as well as supporting rotary rollers 9 on a hydraulic drive, which are able to diverge crosswise (with respect to the longitudinal axis of the mill) and move in reverse up to the stop against the pipe blank 10 surface.

[0036] Supporting-rotary rollers 9 are installed near assembly mandrels 5.

[0037] To enable pipe blank 10 to rotate into the welding position (12-hour and 6-hour positions), welding trolley 8 is fitted out with rotary rollers 11.

[0038] For weld application inside the pipe blank, the mill is fitted out with cantilever crossbar 13 mounted on supporting assembly 12, with second welding head 14.

[0039] The mill is fitted out with a control system including control unit 15 and a system of triangulation sensors 16, 17 installed on assembly mandrels 5 and sensors 18 to guide the pipe blank edge butt-joint installed on welding heads 4 and 14 respectively. First-group sensors 16 detect the profile of pipe blank 10 in the transverse section located in the area between assembly mandrels 5; second-group sensors 17 detect the profile of pipe blank 10 edge butt-joint. Control unit 15 located inside the control station in operator's cab 19 is connected to the monitors (not shown) located at the control station displaying data on measurement of the pipe blank profile, on the profile of the assembled edge butt-joint, on the parameters of pipe blank compression with mandrel stops, on the welding process modes, and on the status of equipment contained in the mill.

[0040] The control system integration into structural equipment of the mill enables to shape the specified ovality of the pipe blank profile during accurate bringing of the pipe blank edges together.

[0041] The drawings show protective shelter 20, which can be made as a framework with three-layer sandwich panel walls; the inside surface of the shelter is coated with matte paint to enhance the reflected laser radiation scattering.

[0042] The claimed mill operates as follows.

[0043] A formed pipe blank is transferred to the welding trolley beyond the working area. By means of hydraulic drive, supporting-rotary rollers 9 diverge into opposite sides to enable welding trolley 8 to move along rail track 7 to the mill zone. Cantilever crossbar 13 with second welding head 14 is placed inside pipe blank 10. Pipe blank 10 is oriented by rotary rollers 11 of welding trolley 8 into 12-hour welding position.

[0044] Assembly mandrels 5 compress pipe blank 10 with hydraulic stops 6 to bring the pipe blank edges together.

[0045] During compression of pipe blank 10, information from sensors 16, 17, 18 displayed on the monitor is analyzed by the operator who, if necessary, adjusts the pipe blank compression by controlling impact of individual stops on the pipe blank.

[0046] Upon completion of the pipe blank assembly, the operator moves welding bridge 3 into the initial welding position. Welding head 4 is guided to the edge butt-joint by its own triangulation sensor 18. The welding process on outside of pipe blank 10 is activated.

[0047] Upon assembly of the pipe blank with the weld on outside, hydraulic stops 6 of assembly mandrels 5 diverge, and supporting-rotary rollers 9 move away from pipe blank 10.

[0048] By means of rotary rollers 11 of welding trolley 8, pipe blank 10 is oriented into 6-hour welding position. Second welding head 14 on cantilever crossbar 13 is lowered to the inside surface of the pipe. Second welding head 14 is guided to the edge butt-joint by its own triangulation sensor 19. The welding process is activated, and welding trolley 8 begins moving at the welding speed toward withdrawal from cantilever crossbar 13, goes out of the work area of the assembly-welding mill and is transferred to other production sections.

[0049] The proposed longitudinal pipe welding and assembly mill enables to manufacture customized high-quality long length large diameter tubes using various welding technologies. The work area of the large diameter assembly and welding mill is convenient for placing various welding technology units: gas metal arc welding, gas tungsten arc welding, submerged multiarc welding, laser, and prospective hybrid laser arc welding.