A full position hot wire TIG welding process for duplex stainless steel pipe

Abstract

The application discloses a kind of duplex stainless steel pipeline full position hot wire TIG welding process, steps are as follows: the bevel oil dirt of pipe to be welded is cleaned, after splicing pipe to be welded, spot welding is fixed, and is carried out with pulse hot wire TIG process Base welding;First, adopt swing hot wire TIG process and carry out multilayer multi-pass filling welding on base, and polishing is needed to joint during welding process;Then, using swing hot wire TIG process carries out covering welding.The welding operation is carried out full position automatic welding by robot, and is divided into three positions of flat welding, vertical welding and overhead welding, and the hot wire current adopts direct current heating.The application aims to provide a kind of hot wire TIG process can be carried out full position welding to pipeline, to solve the problem of base welding leakage, incomplete penetration and filling welding unmelting.

Description

Technical Field

[0001] The present invention relates to the technical field of arc welding, and in particular to an all-position hot wire TIG welding process for duplex stainless steel pipelines. Background Art

[0002] Oil and gas resources play a vital role in industrial manufacturing and social life, and are among the most widely used resources in today's society. Long-distance transportation of oil and gas resources typically relies on pipelines. Duplex stainless steel pipelines can meet the complex demands of oil and gas extraction and transportation environments, and have broad application prospects in oil and gas transportation. Welding is a key connection method for offshore pipelines. However, most duplex stainless steel pipelines in offshore engineering are still welded manually using TIG welding, which is labor-intensive, inefficient, and has inconsistent weld quality. Hot-wire TIG welding heats the wire before feeding it into the molten pool to promote melting, improve its spreadability, and increase welding efficiency. Integration with robotic systems can enable fully automated welding. Pipeline welding is generally divided into root welding, filler welding, and cap welding. The process is complex and requires extremely high welding parameters. If the welding parameters are not appropriate, incomplete penetration or leaking welds are likely to occur in the root weld, while lack of fusion defects are more likely to occur in the filler and cap welds, seriously affecting weld quality and pipeline formation and performance. Therefore, there is an urgent need for a method that can perform all-position welding of pipelines using a hot wire TIG process to solve the problems of base weld leakage, incomplete penetration and lack of fusion in the filler weld. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a method for performing all-position welding of pipelines using a hot wire TIG process, so as to solve the problems of weld leakage, incomplete penetration and lack of fusion in the filler weld.

[0004] To achieve the above object, the present invention is implemented through the following technical solutions:

[0005] A full-position hot wire TIG welding process for duplex stainless steel pipes, the steps are as follows:

[0006] (1) Clean the oil stains on the groove of the pipe to be welded, fix the pipe to be welded after splicing, and use the pulse hot wire TIG process for base welding. The peak current of base welding is 300-330A, the peak wire feeding speed is 0.8-1.0m / min, the base current is 40%-45% of the peak current, the base wire feeding speed is 42%-48% of the peak wire feeding speed, the duty cycle is 50%-55%, the pulse frequency is 1.0-1.5Hz, and the arc starting current is 100%-110%, arc ending current is 50%-60% of the peak current, wire feeding delay time is 0.5-0.8s at the beginning, 0.2-0.4s at the end, wire drawing amount at the end is 1-3mm, arc starting dwell time is 0.3-0.5s, welding speed from flat welding position to vertical welding position is 10-11cm / min, welding speed from vertical welding position to overhead welding position is 9-10cm / min, and welding speed at overhead welding position is 8-9cm / min;

[0007] (2) First, use the swing hot wire TIG process to perform multi-layer and multi-pass filling welding on the base. The joint needs to be polished during the welding process. The current of the filling welding is 180-200A, the wire feeding speed is 1.2-1.5m / min, the arc starting current is 80%-85% of the welding current, the arc ending current is 50%-60% of the welding current, the wire feeding time at the beginning is 0.5-0.8s, the wire feeding time at the end is 0.2-0.4s, the wire drawing amount at the end is 1-3mm, and the arc starting dwell time is 0.3-0 .5s, the welding gun swing frequency is 1.7-2Hz; there are four filling layers on the base, the first filling layer has a welding gun swing width of 2.8-3.2mm and a welding speed of 10-11m / min; the second filling layer has a welding gun swing width of 4-4.5mm and a welding speed of 9-10m / min; the third filling layer has a welding gun swing width of 5.5-6mm and a welding speed of 8-9m / min; the fourth filling layer adopts double-pass filling, with a welding gun swing width of 3.5-4mm and a welding speed of 10-11m / min;

[0008] (3) The cap welding is then performed using the swing hot wire TIG process. The cap welding is divided into three caps, and three passes are used for capping. The arc starting current is 80%-85% of the welding current, the arc ending current is 30%-40% of the welding current, the wire feeding delay time at the beginning is 0.5-0.8s, the wire feeding delay time at the end is 0.2-0.4s, the wire drawing amount at the end is 1-3mm, and the arc starting dwell time is 0.3-0.5s; the welding current of the first cap is 180-200A, the wire feeding speed is 1.2-1.5m / min, and the welding gun swing frequency is 1.7- 2Hz, swing width is 5.5-6mm, welding speed is 9-10m / min; the welding current of the second cover is 150-170A, wire feeding speed is 1.0-1.3m / min, welding gun swing frequency is 1.7-2Hz, swing width is 4.3-4.8mm, welding speed is 10-11m / min; the welding current of the third cover is 150-170A, wire feeding speed is 0.9-1.1m / min, welding gun swing frequency is 1.7-2Hz, swing width is 3.8-4.3mm, welding speed is 10-11m / min.

[0009] Furthermore, the welding operation is performed by a robot to perform full-position automatic welding, which is divided into three positions: flat welding, vertical welding and overhead welding.

[0010] Furthermore, the heating wire current adopts direct current heating, and the current is 100-150A.

[0011] Furthermore, in step (1), the groove is a single-sided 30° V-shaped groove, the groove adopts a blunt edge-free, zero-gap butt joint method, and TIG spot welding is adopted after assembly. The arc current of the spot welding is 100-200A and the welding time is 2-3s.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] This invention uses a pulsed hot wire TIG process for base welding. The base layer has four filler layers and three cover layers. The weld seam is dense and uniform after formation, eliminating issues such as incomplete penetration and leaky welds. It also has strong adaptability to root protrusions and misalignment, eliminating defects such as incomplete fusion and incomplete penetration. Furthermore, the welding torch is swiveled during the filler weld, reducing the number of weld passes and improving welding efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Schematic diagram of the arrangement of the filling layer and the cover surface on the breach in the present invention;

[0015] Figure 2 This is a bottom weld formation diagram in the present invention;

[0016] Figure 3 It is the filling weld formation diagram in the present invention;

[0017] Figure 4 This is the cover weld formation diagram of the present invention.

[0018] Reference numerals:

[0019] 1- base, 2- first filling layer, 3- second filling layer, 4- third filling layer, 5- fourth filling layer, 6- first covering surface, 7- second covering surface, 8- third covering surface. DETAILED DESCRIPTION

[0020] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0021] like Figure 1 As shown, a full-position hot wire TIG welding process for duplex stainless steel pipes has the following steps:

[0022] (1) Clean the oil stains on the groove of the pipe to be welded, and then spot weld the pipes to be welded together. The welding operation is performed by a robot for full-position automatic welding, which is divided into three positions: flat welding, vertical welding, and overhead welding. The pulse hot wire TIG process is used for base welding, and the hot wire current is DC heating with a current of 100-150A. Robots that can perform full-position automatic welding, such as FANUC robots, commonly used models include ARC Mate 120iD, M-710iC, M-410iB, R-2000iC, etc. Panasonic robots, commonly used models include G4 series and TM series.

[0023] The groove is a single-sided 30° V-shaped groove, and the groove adopts a blunt-edge-free, zero-gap butt joint method. After assembly, TIG spot welding is adopted, the arc current of the spot welding is 100-200A, and the welding time is 2-3s.

[0024] The peak current of base welding 1 is 300-330A, the peak wire feeding speed is 0.8-1.0m / min, the base current is 40%-45% of the peak current, the base wire feeding speed is 42%-48% of the peak wire feeding speed, the duty cycle is 50%-55%, the pulse frequency is 1.0-1.5Hz, the arc starting current is 100%-110% of the peak current, the arc ending current is 50%-60% of the peak current, the wire feeding lag time at the beginning is 0.5-0.8s, the wire feeding lag time at the end is 0.2-0.4s, the wire drawing amount at the end is 1-3mm, the arc starting dwell time is 0.3-0.5s, the welding speed from the flat welding position to the vertical welding position is 10-11cm / min, the welding speed from the vertical welding position to the overhead welding position is 9-10cm / min, and the welding speed at the overhead welding position is 8-9cm / min.

[0025] (2) First, use the swinging hot wire TIG process to perform multi-layer and multi-pass filler welding on the base 1. The joint needs to be polished during the welding process. The current of the filler welding is 180-200A, the wire feeding speed is 1.2-1.5m / min, the arc starting current is 80%-85% of the welding current, the arc ending current is 50%-60% of the welding current, the wire feeding delay time at the beginning is 0.5-0.8s, the wire feeding delay time at the end is 0.2-0.4s, the wire drawing amount at the end is 1-3mm, the arc starting dwell time is 0.3-0.5s, and the welding gun swing frequency is 1.7-2Hz.

[0026] There are four filling layers on the base 1. The first filling layer 2 has a welding gun swing width of 2.8-3.2mm and a welding speed of 10-11m / min; the second filling layer 3 has a welding gun swing width of 4-4.5mm and a welding speed of 9-10m / min; the third filling layer 4 has a welding gun swing width of 5.5-6mm and a welding speed of 8-9m / min; the fourth filling layer 5 adopts double-pass filling, with a welding gun swing width of 3.5-4mm and a welding speed of 10-11m / min.

[0027] (3) Then use the swing hot wire TIG process to perform cap welding. Cap welding is divided into three caps, and three welds are used for capping. The arc starting current is 80%-85% of the welding current, the arc ending current is 30%-40% of the welding current, the wire feed delay time at the beginning is 0.5-0.8s, the wire feed delay time at the end is 0.2-0.4s, the wire drawing amount at the end is 1-3mm, and the arc dwell time is 0.3-0.5s.

[0028] The welding current of the first cover surface 6 is 180-200A, the wire feeding speed is 1.2-1.5m / min, the welding gun swing frequency is 1.7-2Hz, the swing width is 5.5-6mm, and the welding speed is 9-10m / min; the welding current of the second cover surface 7 is 150-170A, the wire feeding speed is 1.0-1.3m / min, the welding gun swing frequency is 1.7-2Hz, the swing width is 4.3-4.8mm, and the welding speed is 10-11m / min; the welding current of the third cover surface 8 is 150-170A, the wire feeding speed is 0.9-1.1m / min, the welding gun swing frequency is 1.7-2Hz, the swing width is 3.8-4.3mm, and the welding speed is 10-11m / min.

[0029] During welding, when the wire feeding speed is high, the thickness of the cladding layer is thick, and it is difficult for heat to reach the root, which can easily cause incomplete penetration; when the wire feeding speed is low, the molten metal may not be able to cover the root, resulting in unfused edges. When the heat input is large, weld penetration is prone to occur at the root; when the heat input is low, the energy is insufficient, which can easily cause incomplete penetration at the root. In the present invention, the base welding adopts a pulsed TIG welding process. The amount of cladding metal can be controlled by adjusting the peak wire feeding speed and the base wire feeding speed. The welding heat input can be controlled by adjusting the peak current, the base current, the duty cycle, and the pulse frequency, thereby avoiding the problems of incomplete penetration and weld penetration.

[0030] The welding parameters used for the bottom welding in this embodiment are as follows:

[0031] The peak current is 325A, the peak wire feeding speed is 0.9m / min, the base current is 43% of the peak current, the base wire feeding speed is 45% of the peak wire feeding speed, the duty cycle is 53%, the pulse frequency is 1.2Hz, the arc starting current is 100% of the base current, the arc ending current is 50% of the base current, the wire feeding delay time at the beginning is 0.6s, the wire feeding delay time at the end is 0.3s, and the arc starting dwell time is 0.4s.

[0032] The welding speed from the flat welding position to the vertical welding position is 10cm / min, the welding speed from the vertical welding position to the overhead welding position is 9cm / min, and the welding speed at the overhead welding position is 8cm / min.

[0033] Due to the existence of gravity in the flat welding and overhead welding positions, the cladding metal will fall, resulting in the lack of fusion on both sides of the weld and the lack of penetration at the root. Figure 2 As shown, different welding speeds are used in different positions of the root welding. By reducing the welding speed, the amount of cladding metal filling and heat input can be increased.

[0034] The welding parameters used for filler layer welding are as follows:

[0035] The welding current of the filling layer is 187A, the wire feeding speed is 1.3m / min, the arc starting current is 84%, the arc ending current is 38%, the wire feeding lag time at the beginning is 0.6s, the wire feeding lag time at the end is 0.3s, the arc starting dwell time is 0.4s, the ending wire drawing amount is 2mm, and the arc starting dwell time is 0.4s.

[0036] For the first filling layer 2, the welding torch had an oscillation width of 2.8 mm, an oscillation frequency of 1.7 Hz, and a welding speed of 10 cm / min. For the second filling layer 3, the welding torch had an oscillation width of 4.3 mm, an oscillation frequency of 1.7 Hz, and a welding speed of 9 cm / min. For the third filling layer 4, the welding torch had an oscillation width of 5.6 mm, an oscillation frequency of 1.7 Hz, and a welding speed of 8 cm / min. The fourth filling layer 5 was welded using a double pass, with a welding torch oscillation width of 3.6 mm, an oscillation frequency of 1.7 Hz, and a welding speed of 10 cm / min.

[0037] The welding parameters used for cover welding are as follows:

[0038] The arc starting current is 84% ​​of the welding current, the arc ending current is 38% of the peak current, the wire feeding delay time is 0.6s at the beginning and 0.3s at the end, the wire drawing amount at the end is 2mm, and the arc starting dwell time is 0.4s.

[0039] The welding current for the first cover 6 was 187A, the wire feed speed was 1.3m / min, the welding gun oscillation frequency was 1.7Hz, the oscillation width was 5.8mm, and the welding speed was 9m / min. The welding current for the second cover 7 was 155A, the wire feed speed was 1.1m / min, the welding gun oscillation frequency was 1.7Hz, the oscillation width was 4.5mm, and the welding speed was 10m / min. The welding current for the third cover 8 was 155A, the wire feed speed was 1.0m / min, the welding gun oscillation frequency was 1.7Hz, the oscillation width was 4.0mm, and the welding speed was 10m / min.

[0040] During the filling welding and cap welding process, when the scanning frequency and scanning amplitude are small, the cladding metal is difficult to spread to the edge of the weld, resulting in unfused defects; when the scanning frequency and scanning amplitude are large, the welding process is unstable and the arc is easy to burn the side wall, resulting in poor weld formation. Figure 3 and Figure 4 As shown in the figure, the welding gun swing is used in the filling welding and the cap welding to promote the spreading of the molten pool metal, which can increase the weld width and avoid the weld from being unfused.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A hot wire TIG welding process for duplex stainless steel pipes in all positions, characterized by: Here are the steps: (1) Clean the oil stains on the groove of the pipe to be welded, fix the pipe to be welded after splicing, and use the pulse hot wire TIG process for base welding. The peak current of base welding is 300-330A, the peak wire feeding speed is 0.8-1.0m / min, the base current is 40%-45% of the peak current, the base wire feeding speed is 42%-48% of the peak wire feeding speed, the duty cycle is 50%-55%, the pulse frequency is 1.0-1.5Hz, and the arc starting current is 100%-110%, arc ending current is 50%-60% of the peak current, wire feeding delay time is 0.5-0.8s at the beginning, 0.2-0.4s at the end, wire drawing amount at the end is 1-3mm, arc starting dwell time is 0.3-0.5s, welding speed from flat welding position to vertical welding position is 10-11cm / min, welding speed from vertical welding position to overhead welding position is 9-10cm / min, and welding speed at overhead welding position is 8-9cm / min; (2) First, use the swing hot wire TIG process to perform multi-layer and multi-pass filling welding on the base. The joint needs to be polished during the welding process. The current of the filling welding is 180-200A, the wire feeding speed is 1.2-1.5m / min, the arc starting current is 80%-85% of the welding current, the arc ending current is 50%-60% of the welding current, the wire feeding time at the beginning is 0.5-0.8s, the wire feeding time at the end is 0.2-0.4s, the wire drawing amount at the end is 1-3mm, and the arc starting dwell time is 0.3-0 .5s, the welding gun swing frequency is 1.7-2Hz; there are four filling layers on the base, the first filling layer has a welding gun swing width of 2.8-3.2mm and a welding speed of 10-11m / min; the second filling layer has a welding gun swing width of 4-4.5mm and a welding speed of 9-10m / min; the third filling layer has a welding gun swing width of 5.5-6mm and a welding speed of 8-9m / min; the fourth filling layer adopts double-pass filling, with a welding gun swing width of 3.5-4mm and a welding speed of 10-11m / min; (3) Then use the swing hot wire TIG process to perform cover welding. The cover welding is divided into three covers, and three welds are used for the cover. The arc starting current is 80%-85% of the welding current, the arc ending current is 30%-40% of the welding current, the wire feeding time is 0.5-0.8s at the beginning, the wire feeding time is 0.2-0.4s at the end, the wire drawing amount is 1-3mm, and the arc starting dwell time is 0.3-0.5s; the welding current of the first cover is 180-200A, the wire feeding speed is 1.2-1.5m / min, and the welding gun swing frequency is 1.7- 2Hz, swing width is 5.5-6mm, welding speed is 9-10m / min; the welding current of the second cover is 150-170A, wire feeding speed is 1.0-1.3m / min, welding gun swing frequency is 1.7-2Hz, swing width is 4.3-4.8mm, welding speed is 10-11m / min; the welding current of the third cover is 150-170A, wire feeding speed is 0.9-1.1m / min, welding gun swing frequency is 1.7-2Hz, swing width is 3.8-4.3mm, welding speed is 10-11m / min.

2. The all-position hot wire TIG welding process for duplex stainless steel pipes according to claim 1, characterized in that: The welding operation is carried out by robots in all positions automatically, which are divided into three positions: flat welding, vertical welding and overhead welding.

3. The all-position hot wire TIG welding process for duplex stainless steel pipes according to claim 1, characterized in that: The heating wire current adopts direct current heating, and the current is 100-150A.

4. The all-position hot wire TIG welding process for duplex stainless steel pipes according to claim 1, characterized in that: In step (1), the groove is a single-sided 30° V-shaped groove, the groove adopts a blunt edge-free, zero-gap butt joint method, and TIG spot welding is adopted after assembly. The arc current of the spot welding is 100-200A and the welding time is 2-3s.

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