Bottom sealing twin arc welding method of large-caliber industrial pure titanium pipelines

A technology of industrial pure titanium and welding methods, applied in welding equipment, arc welding equipment, manufacturing tools, etc., can solve the problems of high welder operation skills, large consumption of argon gas, slow welding speed, etc., and achieve easy control of weld formation The effect of high quality, saving argon filling cost, and fast welding speed

Active Publication Date: 2011-05-25
SINOPEC TENTH CONSTR
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  • Summary
  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In this case, it is easy to cause the welded joint to produce overheated structure, the grain becomes coarse, and the brittleness is serious.
[0003] When welding the back cover of large-caliber industrial pure titanium pipes (Φ≥600mm), use traditional argon-filled protection (two sections inside the nozzle are closed with 400mm), single-sided welding and double-sided forming welding process, due to the requirement of single-sided welding and double-sided forming, welders welding At the same time, it is necessary to take into account the internal forming quality of the titanium tube, and the groove gap is required to be 3 to 4mm. Sometimes arc-breaking welding is used, which requires high welding skills, so the welding speed is slow, the efficiency is low, the argon gas consumption is large, and the waste is serious, resulting in high cost.
Due to the welder's technical operation, the internal weld seam of single arc back sealing welding often has surface defects such as concave, undercut, incomplete fusion, and incomplete penetration. The seam quality and RT flaw detection are qualified. At the same time, when ordinary single-arc welding is used for bottom sealing, filling, and cover welding, the welding seam requires welding torches, drag covers, and the interior of the pipeline to be protected by argon at the same time. The large consumption of argon has always been a problem for large-caliber titanium. Difficulties in pipe welding

Method used

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  • Bottom sealing twin arc welding method of large-caliber industrial pure titanium pipelines
  • Bottom sealing twin arc welding method of large-caliber industrial pure titanium pipelines
  • Bottom sealing twin arc welding method of large-caliber industrial pure titanium pipelines

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Experimental program
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Effect test

Embodiment 1

[0034] Titanium pipe Φ600×12mm pipe process parameters

[0035] 1. Clean up the oil and oxide on the surface of welding wire and weldment;

[0036] 2. V-shaped bevel processing on the nozzle;

[0037] 3. Carry out pipe assembly, the groove gap is 1mm;

[0038] 4. Two welding torches inside and outside the titanium pipeline work together to weld the titanium pipeline. A tungsten argon arc welding torch with a protective tow cover is used. When welding, the welding direction is followed. 25L / min, inner torch nozzle argon flow 15L / min, outer torch drag hood argon flow 25L / min, inner torch drag hood argon flow 25L / min, outer torch current 140A, inner torch current 50A, outer torch voltage 14V , the voltage of the inner welding torch is 13V, the welding speed of the outer welding torch is 95mm / min, the welding speed of the inner welding torch is 95mm / min, and the distance between the front and rear arcs of the inner and outer welding torches is 4mm.

[0039] 5. The arc of the ex...

Embodiment 2

[0045] Titanium pipe Φ800×12mm pipe process parameters

[0046] 1. Clean up the oil and oxide on the surface of welding wire and weldment;

[0047] 2. V-shaped bevel processing on the nozzle;

[0048] 3. Carry out pipe assembly, the groove gap is 1.5mm;

[0049] 4. Two welding torches inside and outside the titanium pipeline work together to weld the titanium pipeline. A tungsten argon arc welding torch with a protective drag cover is used. When welding, the welding torch nozzle is in front of the protective drag cover and the argon flow rate of the outer welding torch nozzle is adjusted according to the welding direction. 30L / min, inner torch nozzle argon flow 20L / min, outer torch drag hood argon flow 30L / min, inner torch drag hood argon flow 30L / min, outer torch current 145A, inner torch current 50A, outer torch voltage 15V , the voltage of the inner welding torch is 14V, the welding speed of the outer welding torch is 100mm / min, the welding speed of the inner welding torc...

Embodiment 3

[0056] Titanium pipe Φ1500×12mm pipe welding

[0057] 1. Clean up the oil and oxide on the surface of welding wire and weldment;

[0058] 2. V-shaped bevel processing on the nozzle;

[0059] 3. Carry out pipe assembly, the groove gap is 2mm;

[0060] 4. Two welding torches inside and outside the titanium pipeline work together to weld the titanium pipeline. A tungsten argon arc welding torch with a protective drag cover is used. When welding, the welding torch nozzle is in front of the protective drag cover and the argon flow rate of the outer welding torch nozzle is adjusted according to the welding direction. 30L / min, inner torch nozzle argon flow 20L / min, outer torch drag hood argon flow 35L / min, inner torch drag hood argon flow 30L / min, outer torch current 150A, inner torch current 60A, outer torch voltage 15V , the voltage of the inner welding torch is 15V, the welding speed of the outer welding torch is 115mm / min, the welding speed of the inner welding torch is 115mm / m...

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Abstract

The invention relates to a bottom sealing twin arc welding method of large-caliber industrial pure titanium pipelines, which belongs to the technical field of pipeline welding and is suitable for root welding of large-caliber (phi is larger than or equal to 600mm) titanium pipelines, equipment and other non-ferrous metals. The method comprises the following steps of: cleaning greasy dirt and oxides on the surfaces of solder wires and weldments; chamfering pipelines; fitting up the pipelines, wherein the fitting-up gap is 1-2mm; and welding the titanium pipelines by simultaneously using two welding guns inside and the outside the titanium pipelines, wherein argon tungsten arc welding guns with protection dragging covers are adopted, during welding, the welding gun nozzles are in the front, and the protective dragging covers are on the back; and the argon flow of the outer welding gun nozzle is 25-30L / min, the argon flow of the inner welding gun nozzle is 15-20L / min, the argon flow of the dragging cover of the outer welding gun is 25-35L / min, the argon flow of the dragging cover of the inner welding gun is 25-30L / min, and the current of the outer welding gun is 140-160A. The method has the advantages of easy control of welding line molding quality, high welding speed, energy and raw material saving, and the like, wherein the welding speed is 3-5 times as fast as single arc welding.

Description

technical field [0001] The double-arc welding method for the back cover of large-diameter industrial pure titanium pipes belongs to the field of pipe welding technology, and is suitable for root welding of large-diameter (Φ≥600mm) titanium pipes, equipment and other non-ferrous metals in various industries. Background technique [0002] Industrial pure titanium is a non-ferrous metal, which is silvery white and has a small specific gravity. Its outstanding features are: high melting point (melting point 1668°C), poor electrical conductivity, small linear expansion coefficient, lower density than iron, high specific strength, high resistivity, very tough and preservative. The weld pool has the characteristics of accumulated heat, large size, long residence time at high temperature and slow cooling rate. In this case, it is easy to cause overheated structure of the welded joint, the grain becomes coarse, and the brittleness is serious. [0003] When welding the back cover of...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23K9/16B23K101/06
Inventor 唐元生马志才
Owner SINOPEC TENTH CONSTR
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