Submerged arc automatic welding pipeline prefabrication method

Abstract

According to the automatic submerged arc welding pipeline prefabricating method, one end of a to-be-welded pipe section is clamped through a rotating device, a rotating tire is supported below the to-be-welded pipe section, and a submerged arc welding machine is arranged above the to-be-welded pipe section; welding seams of the pipe sections to be welded are welded through automatic submerged arc welding, argon arc welding wires are made into rolled welding wires, the welding wires are installed on a disc-shaped welding wire reel, the welding wire reel is connected with a submerged arc welding machine, and a welding gun extends out of the submerged arc welding machine and is located above a butt joint seam of the two pipe sections to be welded; a contact tube capable of allowing a welding wire with the diameter being 2.4 to pass through and a double-tube type welding flux are adopted, welding is conducted at the speed of 410 mm / min, the voltage is 34 V, the current is 300 A, and the heat input is 1.49. The automatic submerged arc welding process is adopted for prefabricating the pipe section, the deposition efficiency of the welding wire is high, the welding speed is four times that of a manual argon arc, the welding efficiency can be improved, the labor cost can be saved, the prefabricating period of the pipe section is greatly shortened, and the production efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the field of prefabrication design and construction of marine ship pipelines, and in particular relates to a submerged arc automatic welding pipeline prefabrication method. Background Art

[0002] In the process of shipbuilding and offshore engineering project construction, a large number of pipe prefabrication projects with special materials are often encountered. Usually, the mature and traditional GTAW or GTAW+SMAW welding process is used for welding. However, if the pipe section has a diameter greater than 8 inches and a wall thickness greater than 20mm, welding according to the traditional process requires a lot of manpower and time, which seriously affects the project schedule. The situations encountered are as follows: 1. FPSO MV27 project, a large number of thick-walled and large-diameter high-strength carbon steel pipes API 5L-X65 and duplex stainless steel S31803 pipe segment prefabrication projects, using GTAW and GTAW+SMAW welding processes. The entire project invested a lot of manpower and time in the pipe segment prefabrication stage.

[0003] 2. For the FPSO MV31 project, a large number of thick-walled and large-diameter duplex stainless steel S31803 pipe sections were prefabricated using GTAW and GTAW+SMAW welding processes, which required a lot of manpower and time.

[0004] 3. In the FPSO MV33 project, in addition to a large number of thick-walled and large-diameter duplex stainless steel S31803, there are also a large number of thick-walled and large-diameter super duplex stainless steel S32760 pipe section prefabrication projects. The GTAW+SMAW welding process is used on site, and the efficiency is improved, but not significantly. Summary of the invention

[0005] In order to solve the above problems, the present invention proposes a submerged arc automatic welding pipeline prefabrication method for a free-fall lifeboat, and the technical solution adopted is: A method for prefabricating a submerged arc automatic welding pipeline, wherein one end of a pipe section to be welded is clamped by a rotating device, a rotating tire is supported below, and a submerged arc welding machine is arranged above the pipe section to be welded.

[0006] Submerged arc automatic welding is used to weld the welds of the pipe sections to be welded. The argon arc welding wire is made into a coiled welding wire, which is installed on a disc-shaped welding wire reel. The welding wire reel is connected to a submerged arc welding machine. The submerged arc welding machine extends a welding gun and is located above the butt joints of the two pipe sections to be welded.

[0007] Use a conductive nozzle that can pass φ2.4 welding wire and a double-tube flux, weld at a speed of 410mm / min, voltage 34V, current 300A, and heat input 1.49. The double-tube type can effectively control the leakage of flux and solve the problem of poor tail protection during the welding wire movement. Choose a flux that matches the argon arc welding wire to replace the argon protection of the argon arc welding wire to ensure welding quality.

[0008] In the above-mentioned submerged arc automatic welding pipeline prefabrication method, further, the diameter of the argon arc welding wire is 2.4.

[0009] The present invention adopts submerged arc automatic welding technology to prefabricate pipe sections. The welding wire has high melting efficiency and the welding speed is 4 times that of manual argon arc. It can not only improve welding efficiency but also save labor costs, greatly shorten the prefabrication period of pipe sections and improve production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a schematic diagram of the operation structure of the present invention; Among them, 1- welding gun, 2- pipe to be welded, 3- tire, 4- rotating device, 5- submerged arc welding machine, 6- coiled welding wire, 7- flux tooling. DETAILED DESCRIPTION

[0011] The present invention will be further described in conjunction with the accompanying drawings.

[0012] A method for prefabrication of submerged arc automatic welding pipelines. Taking the MV33 module project as an example, the total number of prefabricated welds in the workshop pipe section is 9101, and the number of welds with a pipe diameter greater than 8 inches and a wall thickness greater than 20 mm is 6929, accounting for 76%. Therefore, in order to solve the above problems, it is planned to improve the conductive nozzle and wire feeding device of the existing pipeline girth automatic welding machine in the workshop, install flux tooling, and change the boxed argon arc welding wire to a coiled submerged arc welding wire, and use the submerged arc welding process to prefabricate and weld this type of special material pipe. Figure 1 As shown, one end of the pipe section to be welded is clamped by a rotating device, a rotating tire is supported below, and a submerged arc welding machine is arranged above the pipe section to be welded.

[0013] Submerged arc automatic welding is used to weld the welds of the pipe sections to be welded. The argon arc welding wire is made into a coiled welding wire, which is installed on a disc-shaped welding wire reel. The welding wire reel is connected to a submerged arc welding machine. The submerged arc welding machine extends a welding gun and is located above the butt joints of the two pipe sections to be welded.

[0014] A conductive nozzle capable of passing φ2.4 welding wire and a double-tube flux were used, and welding was performed at a speed of 410 mm / min, a voltage of 34 V, a current of 300 A, and a heat input of 1.49.

[0015] The deposition efficiency of φ3.2 hand welding rod, φ2.4 argon arc welding wire, and φ2.4 submerged arc welding wire are 55%, 95%, and 99% respectively; the welding speeds of the three welding materials are usually 100mm / min, 150mm / min, and 400mm / min respectively. Therefore, if the submerged arc automatic welding process is used for pipe segment prefabrication, the welding wire has the highest deposition efficiency, and the welding speed is 4 times that of the argon arc, which can not only improve welding efficiency, but also save labor costs, greatly shorten the prefabrication period of the pipe segment, and improve production efficiency.

Claims

1. A method for prefabricating a submerged arc automatic welding pipeline, characterized in that: One end of the pipe section to be welded is clamped by a rotating device, a rotating tire is supported below, and a submerged arc welding machine is arranged above the pipe section to be welded; The weld seams of the pipe sections to be welded are welded by submerged arc automatic welding. The argon arc welding wire is made into a coiled welding wire, and the welding wire is installed on a disc-shaped welding wire reel. The welding wire reel is connected to a submerged arc welding machine. The submerged arc welding machine extends a welding gun and is located above the butt joints of the two pipe sections to be welded. A conductive nozzle capable of passing φ2.4 welding wire and a double-tube flux were used, and welding was performed at a speed of 410 mm / min, a voltage of 34 V, a current of 300 A, and a heat input of 1.

49.

2. A method for prefabricating a submerged arc automatic welding pipeline according to claim 1, characterized in that: The diameter of the argon arc welding wire is 2.4.

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