A kind of butt welding method of bimetal composite pipe girth weld
A bimetallic composite pipe and welding method technology, applied in welding equipment, metal processing, welding accessories, etc., can solve the difficulty of increasing the quality control of welds, increase the brittleness of weld joints, and the corrosion resistance of bimetallic composite pipe welds to improve the quality control level of welds, avoid welding, and simplify the welding process
Active Publication Date: 2016-11-16
BC P INC CHINA NAT PETROLEUM CORP +1
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Problems solved by technology
Secondly, the dilution effect caused by the diffusion of elements between the base pipe and the liner will lead to a decrease in the corrosion resistance of the weld of the bimetal composite pipe, and produce a martensitic structure in the area near the fusion line, thereby increasing the corrosion resistance of the weld. Brittleness of joints
In addition, in order to prevent the interdiffusion of alloy elements between the base pipe and the liner, the existing welding method is to carry out transition welding after root welding. The transition welding belongs to dissimilar metal welding, which also increases the difficulty of weld quality control
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[0036] For the butt girth welding of bimetal composite pipe Φ508mm L245 steel and 316L stainless steel bimetal composite pipe, the wall thickness of the base pipe is 14.2mm, and the wall thickness of the liner pipe is 2.5mm.
[0037] Process a 60±5° welding groove at the end of the bimetallic composite pipe to be welded, and the gap between the two ends is 2.0-3.0mm. First, tungsten argon arc welding and TGS-316L stainless steel argon arc welding wire are used for root welding of 316L stainless steel liner. After the welding is completed, the surface of the primer layer is ground and smoothed. then attached figure 2 As shown, use molybdenum wire with a diameter of 40 μm to wrap a layer of molybdenum tape with a thickness of ≤0.7mm (=14.2mm×5%) on the surface of the bottom welding layer, and the molybdenum tape wraps the entire bottom welding seam. Since the melting point of Mo is about 2600°C, and the melting point of 316L and L245 is not more than 1500°C, the Mo layer will...
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Abstract
The invention discloses a circumferential weld butt welding method of a double-metal composite pipe. The method includes: forming a welding groove in the carbon steel base pipe of the to-be-welded double-metal composite pipe, wherein the welding groove is V-shaped and forms two notches; using argon tungsten-arc welding to weld a liner pipe so as to form a corrosion-resistant alloy welding area; polishing to smooth the corrosion-resistant alloy welding area after welding, and winding a layer of high-temperature-resistant non-melt layer on the surface of the corrosion-resistant alloy welding area; using manual arc welding to complete the welding of the carbon steel base pipe to form a carbon steel welding area so as to complete the circumferential weld butt welding of the double-metal composite pipe. The method has the advantages that the high-temperature-resistant non-melt layer is introduced between the carbon steel base pipe at the welding connector of the double-metal composite pipe and the corrosion-resistant alloy liner pipe, the carbon steel base pipe is effectively separated from the melting area of the liner pipe due to the fact that the melting point of the high-temperature-resistant non-melt layer is much higher than that of the carbon steel base pipe and the liner pipe, diffusion of the alloy elements of the carbon steel base pipe and the liner pipe is avoided, and weld quality control difficulty is lowered.
Description
【Technical field】 [0001] The invention belongs to the technical field of welding, and in particular relates to a butt welding method for girth welds of bimetal composite pipes. 【Background technique】 [0002] Bimetal composite pipe is a kind of ordinary carbon steel as the base pipe, with stainless steel, nickel-based alloy, Hastelloy and other corrosion-resistant alloys as the liner, through mechanical spinning, explosive compounding, drawing compounding, hydraulic compounding, etc. An economical corrosion-resistant pipe produced. The base pipe gives full play to the excellent mechanical properties and cheap advantages of carbon steel pipe, and is responsible for pressure bearing and rigid support of the pipe; the lining pipe is responsible for corrosion resistance, and the thickness of the lining pipe is only 0.3-4.0mm, which effectively saves the cost of the pipe. cost. Therefore, bimetallic composite pipes are widely used in oil and gas gathering and transportation pip...
Claims
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IPC IPC(8): B23K9/028B23K9/32
CPCB23K9/00B23K9/028B23K9/167B23K2101/06
Inventor 上官丰收常泽亮李发根孟繁印李广山
Owner BC P INC CHINA NAT PETROLEUM CORP