All-position hot wire TIG (Tungsten Inert Gas) welding process for duplex stainless steel pipeline

Abstract

The invention discloses an all-position hot wire TIG (Tungsten Inert Gas) welding process for a duplex stainless steel pipeline, which comprises the following steps of: cleaning greasy dirt on a groove of a to-be-welded pipeline, splicing the to-be-welded pipeline, then carrying out spot welding and fixing, and carrying out backing welding by adopting a pulse hot wire TIG process; the method comprises the following steps: firstly, carrying out multi-layer and multi-pass filling welding on a base by adopting a swinging hot wire TIG (Tungsten Inert Gas) process, and polishing joints in the welding process; and then cosmetic welding is conducted through the swing hot wire TIG technology. The welding operation is carried out through a robot in an all-position automatic welding mode, the welding operation is divided into a flat welding position, a vertical position welding position and an overhead position welding position, and the hot wire current adopts direct current heating. The invention aims to provide a hot wire TIG (Tungsten Inert Gas) process for carrying out all-position welding on a pipeline so as to solve the problems of welding leakage and incomplete penetration of backing welding and incomplete fusion of filling welding.

Description

Technical Field

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

[0002] Oil and gas resources play an important role in industrial manufacturing and social life, and are one of the most widely used resources in today's society. Long-distance transportation of oil and gas resources usually relies on pipelines. Duplex stainless steel pipelines can meet the complex requirements of oil and gas exploitation and transportation environments, and have broad application prospects in oil and gas transportation. Welding is one of the important connection methods for marine pipelines. However, most of the duplex stainless steel pipelines in marine engineering are still welded manually by TIG welding, which has high labor intensity, low welding efficiency and unstable welding quality. Hot wire-TIG welding is to heat the welding wire before feeding it into the molten pool to promote its melting, improve its spreadability and improve welding efficiency. It can be integrated with the robot system to achieve full-position automatic welding. Pipeline welding is generally divided into base welding, filling welding and cover welding. The process is complicated and the requirements for welding process parameters are extremely high. Once the welding parameters are unreasonable, it is very easy to have defects such as incomplete penetration or welding leakage during base welding, and incomplete fusion defects are prone to occur in filling welding and cover welding, which seriously affect the welding quality and pipeline forming and performance. Therefore, there is an urgent need for a hot wire TIG process to perform all-position welding on pipelines to solve the problems of base welding leakage, incomplete penetration and incomplete fusion of filling welding. Summary of the invention

[0003] The purpose of the present invention is to overcome the deficiencies in the above-mentioned prior art and to provide a method for hot wire TIG process to perform all-position welding on pipelines to solve the problems of welding leakage, incomplete penetration and incomplete fusion of filler welds.

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

[0005] A duplex stainless steel pipe all-position hot wire TIG welding process, 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 by spot welding after splicing, and use the pulse hot wire TIG process for base welding;

[0007] (2) First, use the swing hot wire TIG process to perform multi-layer and multi-pass filling welding on the base, and the joints need to be polished during the welding process;

[0008] (3) Then use the swing hot wire TIG process to perform cover welding.

[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 after assembly, TIG spot welding is adopted, the arc current of the spot welding is 100-200A, and the welding time is 2-3s.

[0012] Furthermore, in step (1), the peak current of the 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 current, 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 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, 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.

[0013] Furthermore, in step (2), 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 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 1.7-2H z; 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.

[0014] Further, in step (3), the 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 peak current, the wire feeding delay time is 0.5-0.8s at the beginning, the wire feeding delay time is 0.2-0.4s at the end, 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, the welding gun swing frequency is 1.7-2Hz, and the swing The swing width is 5.5-6mm, and the welding speed is 9-10m / min; the welding current of the second cover 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 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.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The present invention adopts pulse hot wire TIG process for base welding. There are four filling layers and three covering layers on the base. After the weld is formed, it is dense and uniform, and there is no problem of incomplete penetration and welding leakage. The root is convex, the misalignment is highly adaptable, and there is no defect such as incomplete fusion and incomplete penetration. In addition, the welding gun is swung during the filling welding, which reduces the number of welding passes and improves the welding efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the arrangement of the filling layer and the cover surface on the breach in the present invention;

[0018] Figure 2 It is the bottom welding seam forming diagram in the present invention;

[0019] Figure 3 It is the formation diagram of the filling weld in the present invention;

[0020] Figure 4 This is a diagram showing the formation of the cover weld in the present invention.

[0021] Reference numerals:

[0022] 1-priming, 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

[0023] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0024] like Figure 1 As shown, a duplex stainless steel pipeline full-position hot wire TIG welding process, the steps are as follows:

[0025] (1) Clean the oil stains on the groove of the pipe to be welded, and fix the pipe to be welded by spot welding after splicing. 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 adopts 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.

[0026] The groove is a single-sided 30° V-shaped groove, the groove adopts a blunt-edge-free, 0-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.

[0027] 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 current, 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.

[0028] (2) First, use the swing hot wire TIG process to perform multi-layer and multi-pass filling welding on the base 1. During the welding process, the joint needs to be polished. 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 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.

[0029] 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.

[0030] (3) Then use the swing hot wire TIG process to perform cap welding. 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 peak 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.

[0031] 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.

[0032] During welding, when the wire feeding speed is high, the thickness of the cladding layer is thicker, and it is difficult for heat to reach the root, which may easily cause incomplete penetration; when the wire feeding speed is low, the molten metal may be difficult to cover the root, resulting in unfused edges. When the heat input is large, welding leaks and penetrations are prone to occur at the root; when the heat input is low, the energy is insufficient, and incomplete penetration of the root is prone to occur. 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 welding leaks and penetrations.

[0033] The welding parameters used for the bottom welding in this embodiment are as follows:

[0034] 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.

[0035] 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.

[0036] Due to the effect of gravity, the cladding metal will fall down in the flat welding and overhead welding positions, resulting in incomplete fusion on both sides of the weld and incomplete penetration at the root. Figure 2 As shown, different welding speeds are used in different positions of the base welding. By reducing the welding speed, the amount of cladding metal filling and heat input can be increased.

[0037] The welding parameters used for the filler layer welding are as follows:

[0038] 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.

[0039] The welding torch swing width of the first filling layer 2 is 2.8 mm, the swing frequency is 1.7 Hz, and the welding speed is 10 cm / min.

[0040] The welding torch swing width of the second filling layer 3 is 4.3 mm, the swing frequency is 1.7 Hz, and the welding speed is 9 cm / min.

[0041] The third filling layer 4 has a welding torch swing width of 5.6 mm, a swing frequency of 1.7 Hz, and a welding speed of 8 cm / min. The fourth filling layer 5 adopts double-pass welding, with a welding torch swing width of 3.6 mm, a swing frequency of 1.7 Hz, and a welding speed of 10 cm / min.

[0042] The welding parameters used for cover welding are as follows:

[0043] The arc starting current is 84% ​​of the welding current, the arc ending current is 38% of the peak current, the wire feeding lag 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.

[0044] The welding current of the first cover 6 is 187A, the wire feeding speed is 1.3m / min, the welding gun swing frequency is 1.7Hz, the swing width is 5.8mm, and the welding speed is 9m / min. The welding current of the second cover 7 is 155A, the wire feeding speed is 1.1m / min, the welding gun swing frequency is 1.7Hz, the swing width is 4.5mm, and the welding speed is 10m / min. The welding current of the third cover 8 is 155A, the wire feeding speed is 1.0m / min, the welding gun swing frequency is 1.7Hz, the swing width is 4.0mm, and the welding speed is 10m / min.

[0045] During the filling welding and capping 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, the arc is easy to burn the side wall, resulting in poor weld formation. Figure 3 and Figure 4 As shown, the welding gun is swung in the filling welding and cap welding to promote the spreading of the molten pool metal, increase the weld width and avoid weld incomplete fusion.

[0046] 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 principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A duplex stainless steel pipeline all-position hot wire TIG welding process, 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 by spot welding after splicing, and use the pulse hot wire TIG process for base welding; (2) First, use the swing hot wire TIG process to perform multi-layer and multi-pass filling welding on the base, and the joints need to be polished during the welding process; (3) Then use the swing hot wire TIG process to perform cover welding.

2. The all-position hot wire TIG welding process for duplex stainless steel pipeline according to claim 1 is characterized by: 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.

3. The all-position hot wire TIG welding process for duplex stainless steel pipeline according to claim 1 is characterized by: The hot 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 pipeline according to claim 1 is characterized by: 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 spot welding is 100-200A and the welding time is 2-3s.

5. The all-position hot wire TIG welding process for duplex stainless steel pipeline according to claim 1 is characterized by: In step (1), the peak current of the 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 current, 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 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, 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.

6. The all-position hot wire TIG welding process for duplex stainless steel pipeline according to claim 1 is characterized by: In step (2), 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 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; 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.

7. The all-position hot wire TIG welding process for duplex stainless steel pipeline according to claim 1 is characterized by: In step (3), the 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 peak current, the wire feeding delay time is 0.5-0.8s at the beginning, the wire feeding delay time is 0.2-0.4s at the end, 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, the welding gun swing frequency is 1.7-2Hz, and the swing width is 1.2-1.5m / min. The thickness of the cover is 5.5-6mm, and the welding speed is 9-10m / min; the welding current of the second cover 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 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.

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