Stainless steel pipe butt welding method

Abstract

The invention belongs to the technical field of pipeline welding, and discloses a stainless steel pipe butt welding method which comprises the following steps: S1, butt welding end faces between stainless steel pipes to be welded or end faces of the stainless steel pipes and pipe accessories; s2, a welding head is moved to the to-be-welded end face combination position, and the stainless steel pipe is driven to rotate or the stainless steel pipe and the pipe accessory are driven to rotate together; if the welding head can run along the whole circle of the end face joint, executing S3; if not, adjusting the position of the stainless steel pipe, the pipe accessory or the welding head to be welded, and then executing S3; s3, the end face to be welded is subjected to whole-circle deep fusion arc welding; and S4, a welding seam is checked. Deep melting arc welding is adopted, and a lock hole is formed through balance of electric arc force formed by current and static pressure and surface tension of liquid metal; when the method is used for welding, the stainless steel pipe and the pipe accessory do not need to be beveled, the welding time is short, the welding efficiency is improved, and welding materials are saved.

Description

Technical Field

[0001] The invention relates to the technical field of pipeline welding, and in particular to a butt welding method for stainless steel pipes. Background Art

[0002] Stainless steel pipes are widely used in shipbuilding. The butt welds of stainless steel pipes require manual argon arc welding for priming and 100% penetration. In addition, traditional argon arc welding requires opening a groove at the end of the pipe wall of the stainless steel pipe, grinding the groove, and then performing multi-layer and multi-pass welding. As a result, the welding time is long and the welding efficiency is low. The interlayer temperature control requirements are high, and the operator qualifications and welding parameters are high. In addition, the consumption of welding wire and argon gas is large. Summary of the invention

[0003] The object of the present invention is to provide a butt welding method for stainless steel pipes, which does not require beveling, shortens the welding time, improves the welding efficiency, and saves welding materials.

[0004] To achieve this object, the present invention adopts the following technical solutions:

[0005] The butt welding method of stainless steel pipe comprises the following steps:

[0006] S1. Align the end faces of the stainless steel pipes to be welded or the end faces of the stainless steel pipes and pipe accessories;

[0007] S2, moving the welding head to the end face joint to be welded, and driving the stainless steel pipe to rotate or driving the stainless steel pipe and the pipe accessories to rotate together; if the welding head can align along the end face joint in a full circle, execute S3; if not, adjust the position of the stainless steel pipe, the pipe accessories or the welding head and then execute S3;

[0008] S3, driving the stainless steel pipe and the pipe accessories to rotate together, and performing full circle deep melting arc welding on the end face to be welded;

[0009] S4. Check the weld.

[0010] In some embodiments, in the step S3, the welding parameters of the deep penetration arc welding can be adjusted during welding to adjust the welding depth.

[0011] In some embodiments, the welding parameters adjusted include the current of the deep penetration arc welding, and the current used in the deep penetration arc welding is 310A-440A.

[0012] In some embodiments, the voltage used for deep penetration arc welding is 14.7V-17.8V.

[0013] In some embodiments, the wire feeding speed of the deep penetration arc welding is 1650mm / min-2250mm / min; the welding speed is 350mm / min-463m / min; and the heat input is 5.9kj / cm-13.4kj / cm.

[0014] In some embodiments, the wall thickness of the stainless steel tube is 2.5 mm-5.5 mm.

[0015] In some embodiments, the reserved distance between the end faces of the stainless steel pipes to be welded or between the end face of the stainless steel pipe and the end face of the pipe accessory is 0-2 mm.

[0016] In some embodiments, the shielding gas used in the deep penetration arc welding is argon gas, and the purity of the argon gas is 99.995%.

[0017] In some embodiments, the gas flow rate of the protective gas is 20 L / min-37 L / min.

[0018] In some embodiments, the welding head is located above the stainless steel tube, and the longitudinal axis of the welding head is perpendicular to the longitudinal axis of the stainless steel tube.

[0019] Beneficial effects of the present invention:

[0020] Deep melting arc welding is used to form a keyhole by balancing the arc force formed by the current with the static pressure and surface tension of the liquid metal. When welding using this method, the stainless steel pipe does not need to be beveled, the welding time is short, the welding efficiency is improved, and welding materials are saved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a flow chart of the stainless steel pipe butt welding method of the present invention. DETAILED DESCRIPTION

[0022] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only the parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0023] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0025] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0026] like Figure 1 As shown, the present invention provides a stainless steel pipe butt welding method, which is used for butt welding between stainless steel pipes or between a stainless steel pipe and a pipe accessory, and the method comprises the following steps:

[0027] S1. Align the end faces of the stainless steel pipes to be welded or the end faces of the stainless steel pipe and the pipe accessories; specifically, the wall thickness of the stainless steel pipe is 2.5 mm-5.5 mm; it is understood that in some embodiments, in order to ensure the quality of welding, the end faces of the stainless steel pipe and the end faces of the pipe accessories can be processed before the end faces are butted to ensure that the end faces are neat. It should be noted here that the pipe accessories can be elbows, flanges, etc.

[0028] In addition, stainless steel pipes or pipe accessories are generally fixed by external fixing devices, which provide fixed position and rotational power. When fixing stainless steel pipes, different external fixing devices can be selected according to the size of the stainless steel pipes. When the size of the stainless steel pipe is large, the external fixing device is provided with a support claw, which extends into the stainless steel pipe and supports the stainless steel pipe; illustratively, the support claw is provided with a plurality of support parts, which are arranged in a ring shape, and each support part is provided with a support drive, so that the stainless steel pipe can be propped up. When the size of the stainless steel pipe is small, a clamping claw that clamps the outer wall of the stainless steel pipe can be used; the above-mentioned support claw and clamping claw both have a rotation drive, so that the stainless steel pipe can be driven to rotate. Exemplarily, the rotation drive can be a motor, and the support drive can be a cylinder, etc. The pipe accessories can also be fixed by one of the above-mentioned fixing parts.

[0029] When the end faces of the stainless steel pipes or the end faces of the stainless steel pipes and the end faces of the pipe accessories are butted against each other, the reserved distance between the end faces is 0-2 mm.

[0030] S2. Move the welding head to the end face joint of the stainless steel pipe to be welded or the end face joint of the stainless steel pipe and the pipe accessory, and drive the stainless steel pipe to rotate. Of course, the stainless steel pipe and the pipe accessory can also be driven to rotate together. Observe the position of the welding head to ensure that it can be aligned with the end face joint to ensure normal welding; specifically, during welding, the welding head is located above the stainless steel pipe, and the longitudinal axis of the welding head is perpendicular to the axis of the stainless steel pipe.

[0031] If the welding head can be aligned along the entire circle of the above-mentioned end face joint, execute S3; if the welding head cannot be aligned along the entire circle of the above-mentioned end face joint, it is possible that the positions of the stainless steel pipe, pipe accessories and welding head are incorrect, so check the positions of the stainless steel pipe, pipe accessories and welding head. If the positions of the three are incorrect, adjust the positions of the stainless steel pipe, pipe accessories and welding head and then execute S3.

[0032] S3. Drive the stainless steel pipe to rotate again together with the pipe accessories, and perform a full circle of deep melting arc welding on the end face to be welded, so as to connect the end faces of the two stainless steel pipes or the stainless steel pipe and the pipe accessories; wherein, driving the stainless steel pipe and the pipe accessories to rotate during welding has higher stability than driving the welding head to rotate, thereby ensuring the quality of welding.

[0033] Deep melting arc welding mainly relies on the arc force formed by the current to balance the static pressure and surface tension of the liquid metal to form a keyhole. Its welding mechanism is that the base material is rapidly heated under the action of the high-temperature arc, and the surface temperature rises to the boiling point in a very short time, and the metal melts or vaporizes. When the metal vaporizes, the generated metal vapor leaves the molten pool at a certain speed. The escape of the metal vapor produces a reaction force on the molten liquid metal, which acts together with the arc pressure to make the surface of the molten pool metal concave downward, forming a small pit, and the molten metal is squeezed to the surrounding of the molten pool. This process continues, and a keyhole is formed in the liquid metal through the dynamic balance between the surface tension of the molten pool metal and the arc pressure.

[0034] When welding, it is necessary to fill in a shielding gas to protect the weld from oxidation. Filling in a shielding gas during welding is a prior art, and its details are not repeated. In the current embodiment, the shielding gas filled is argon gas, and its concentration is 99.995%. When welding, the gas flow rate of argon gas is 20L / min-37L / min; further, when welding, the wire feeding speed used in deep melting arc welding is 1650mm / min-2250mm / min; the welding speed is 350mm / min-463mm / min; and the heat input is 5.9kj / cm-13.4kj / cm.

[0035] In addition, when welding, the parameters of deep penetration arc welding can be adjusted to adjust the depth of welding; more specifically, when adjusting the welding parameters, it is mainly to adjust the current of deep penetration arc welding to control the depth of welding. In the current embodiment, the current used in deep penetration arc welding is 310A-440A. It is understandable that the current can also be indirectly adjusted by adjusting the voltage of deep penetration arc welding. The voltage used in deep penetration arc welding is 14.7V-17.8V.

[0036] S4. After welding is completed, check the weld to ensure complete welding; specifically, after completing a full circle of welding, stop the welding operation of the welding head, and then drive the stainless steel pipe to rotate one circle again. While rotating, the operator observes whether the weld is qualified and makes a record, and then removes the stainless steel pipe.

[0037] This method uses deep melting arc welding, which relies on the arc force formed by the current to balance the static pressure and surface tension of the liquid metal to form a keyhole. When welding using this method, the stainless steel pipe does not need to be beveled, the welding time is short, the welding efficiency is improved, and welding materials are saved.

[0038] The following table shows the performance test results of some stainless steel pipes after using the above welding method:

[0039]

[0040] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for butt welding of stainless steel pipes, characterized in that: It includes the following steps: S1. Align the end faces of the stainless steel pipes to be welded or the end faces of the stainless steel pipes and pipe accessories; S2, moving the welding head to the end face joint to be welded, and driving the stainless steel pipe to rotate or driving the stainless steel pipe and the pipe accessories to rotate together; if the welding head can align along the end face joint in a full circle, execute S3; if not, adjust the position of the stainless steel pipe, the pipe accessories or the welding head and then execute S3; S3, driving the stainless steel pipe and the pipe accessories to rotate together, and performing full circle deep melting arc welding on the end face to be welded; S4. Check the weld.

2. The stainless steel pipe butt welding method according to claim 1, characterized in that: In the step S3, the welding parameters of the deep penetration arc welding can be adjusted during welding to adjust the welding depth.

3. The stainless steel pipe butt welding method according to claim 2, characterized in that: The adjusted welding parameters include the current of the deep penetration arc welding, and the current used in the deep penetration arc welding is 310A-440A.

4. The stainless steel pipe butt welding method according to claim 1, characterized in that: The voltage used in the deep penetration arc welding is 14.7V-17.8V.

5. The stainless steel pipe butt welding method according to claim 1, characterized in that: The wire feeding speed of the deep melting arc welding is 1650mm / min-2250mm / min; the welding speed is 350mm / min-463m / min; and the heat input is 5.9kj / cm-13.4kj / cm.

6. The method for butt welding of stainless steel pipes according to claim 1, characterized in that: The wall thickness of the stainless steel tube is 2.5 mm-5.5 mm.

7. The stainless steel pipe butt welding method according to claim 1, characterized in that: The reserved distance between the end faces of the stainless steel pipes to be welded or between the end face of the stainless steel pipe and the end face of the pipe accessory is 0-2 mm.

8. The stainless steel pipe butt welding method according to claim 1, characterized in that: The shielding gas used in the deep penetration arc welding is argon gas, and the purity of the argon gas is 99.995%.

9. The method for butt welding of stainless steel pipes according to claim 8, characterized in that: The gas flow rate of the protective gas is 20L / min-37L / min.

10. The stainless steel pipe butt welding method according to claim 1, characterized in that: The welding head is located above the stainless steel pipe, and the longitudinal axis of the welding head is perpendicular to the length axis of the stainless steel pipe.

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