Single-side full penetration welding process for stainless steel inclined T-shaped joint

Abstract

The invention relates to a single-side full penetration welding process for a stainless steel inclined T-shaped joint, and belongs to the technical field of welding. According to the technical scheme, a laser-MIG composite welding method is adopted, and welding is conducted from the obtuse angle side of the inclined T-shaped connector; in the welding direction, the laser beam is in front of the MIG electric arc, and the distance d1 between the laser beam and the MIG welding wire on the surface of the bottom plate is 0-15 mm; in the direction perpendicular to the welding direction, the distance d2 between the MIG welding wire and the edge of the rib plate is 0-3 mm, and the distance d3 between the spot of the laser beam and the edge of the rib plate is 0-2 mm; and laser beam spots swing on the surface of the workpiece, and the swing speed is 80-300 mm / min. The laser-MIG / MAG hybrid welding full penetration welding process is utilized, welding is conducted from the obtuse angle side of the inclined T-shaped connector, a full penetration welding line on the other side can be achieved, the welding process is stable, the welding efficiency is high, penetration of the back face of the welding line is uniform and consistent, and stress concentration and the corrosion cracking tendency can be effectively avoided.

Description

Technical Field

[0001] The invention relates to a single-side full penetration welding process for a stainless steel inclined T-shaped joint, belonging to the technical field of welding. Background Art

[0002] The oblique T-joint is a common joint form in the field of welding. It refers to a T-joint where two workpieces intersect at an angle and are not at right angles. Stainless steel oblique T-joints are widely used in tank containers, pressure pipes, power equipment, nuclear power, automobile manufacturing, shipbuilding and other fields. They are generally used for sealing and conveying fluids. For example, on the outside of the pipes of some power equipment that circulate hot fluids, a certain number of stainless steel components are welded as heat pipes. An oblique T-shaped weld will be formed between these stainless steel components and the main pipe, such as Figure 1 As shown in the figure, the heat dissipation pipe needs to be filled with fluid of specific temperature and medium to ensure that the transportation and storage conditions of the medium in the main pipe meet the requirements. Since one or both sides of these oblique T-shaped joints are in direct contact with fluid of specific material and temperature, it is very easy to cause stress concentration and joint corrosion, resulting in leakage and affecting the use of the product.

[0003] For this kind of stainless steel oblique T-joint with thin rib plate thickness, MIG welding is generally used to weld from the obtuse angle side. In addition to the slow welding speed and low efficiency, this method cannot form a stable full penetration weld. It is easy to form a sharp angle or an incompletely melted gap on the acute angle side. Long-term use will accumulate impurities, causing corrosion. Increasing the penetration depth and forming a stable full penetration weld is one of the main methods to solve the above problems. Laser-MIG hybrid welding has a larger penetration depth than single MIG welding. When welding a T-shaped weld with a thick rib plate and a right angle or nearly right angle between the rib plate and the bottom plate, full penetration welding can be achieved. However, when the rib plate is thin, due to the high energy density of the laser beam, once the laser "keyhole" is formed, one side of the rib plate will be welded and the weld cannot be formed; in addition, since the laser beam cannot penetrate the bottom plate, a "keyhole-shaped" pore will be formed, which seriously affects the welding quality. Summary of the invention

[0004] The purpose of the present invention is to provide a single-sided full penetration welding process for a stainless steel inclined T-joint, which is suitable for an inclined T-joint with an angle α5 between the rib and the bottom plate in the range of 10°-50° and a rib thickness in the range of 0.8mm-6mm. By using a laser-MIG / MAG composite welding full penetration welding process, stable penetration can be achieved on the back side of the weld, thereby reducing stress concentration and corrosion, and having high welding efficiency, thereby solving the above-mentioned problems existing in the background technology.

[0005] The technical solution of the present invention is: A single-side full penetration welding process for a stainless steel oblique T-shaped joint adopts a laser-MIG composite welding method and performs welding from the obtuse angle side of the oblique T-shaped joint; along the welding direction, the laser beam is in front and the MIG arc is in the back, and the distance d1 between the laser beam and the MIG welding wire on the bottom plate surface is 0-15 mm; perpendicular to the welding direction, the distance d2 between the MIG welding wire and the edge of the rib plate is 0-3 mm, and the distance d3 between the laser beam spot and the edge of the rib plate is 0-2 mm; the laser beam spot swings on the workpiece surface, and the swing speed is 80 mm / min-300 mm / min.

[0006] Furthermore, in a plane parallel to the welding direction, the angle α1 between the MIG welding gun and the base plate is 60°-90°, and the angle α2 between the laser beam and the base plate is 45°-100°; in a plane perpendicular to the welding direction, the angle α3 between the MIG welding gun and the base plate is 50°-80°, and the angle α4 between the laser beam and the rib is 60°-110°.

[0007] Furthermore, a swing distance L1 of the laser beam spot perpendicular to the welding direction is 0.2-1 mm, and a swing distance L2 of the laser beam spot along the welding direction is 0.5-3 mm.

[0008] Furthermore, the laser power is 500W-6000W, the defocus is -2mm-+5mm, the MIG welding current is 100A-350A, and the welding speed is 300mm / min-2100mm / min.

[0009] Furthermore, the angle α5 between the rib plate and the bottom plate ranges from 10° to 50°, and the thickness of the rib plate ranges from 0.8 mm to 6 mm.

[0010] The positive effects of the present invention are as follows: by utilizing the laser-MIG / MAG composite welding full penetration welding process, a full penetration weld can be achieved on the other side by welding from one side of the obtuse angle of the inclined T-shaped joint. The welding process is stable, the welding efficiency is high, and the penetration on the back side of the weld is uniform and consistent, which can effectively avoid stress concentration and corrosion cracking tendency. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 A schematic diagram of an oblique T-shaped joint formed by a heat dissipation pipe according to the background technology of the present invention; Figure 2 It is a welding schematic diagram of the present invention (axial view); Figure 3 This is a schematic diagram of welding of the present invention (perpendicular to the welding direction); Figure 4 This is a schematic diagram of welding of the present invention (parallel to the welding direction); Figure 5 This is a schematic diagram of welding of the present invention (viewed from top); Figure 6This is a photo of the weld surface in Example 1 of the present invention; Figure 7 The macroscopic metallographic structure of the cross section of the weld in the first embodiment of the present invention; Figure 8 This is a photo of the weld surface in Example 2 of the present invention; Fig. 9 This is the macroscopic metallographic structure of the weld cross section in the second embodiment of the present invention; In the figure: 1, MIG welding gun, 2, laser beam, 3, rib plate, 4, bottom plate, 5, MIG welding wire, 6, main pipe, 7, oblique T-shaped joint, 8, heat dissipation pipe; α1, the angle between the MIG welding gun and the bottom plate in the plane parallel to the welding direction, α2, the angle between the laser beam and the bottom plate in the plane parallel to the welding direction, α3, the angle between the MIG welding gun and the bottom plate in the plane perpendicular to the welding direction, α4, the angle between the laser beam and the rib plate in the plane perpendicular to the welding direction, α5, the angle between the rib plate and the bottom plate; d1, the distance between the laser beam and the MIG welding wire on the bottom plate surface along the welding direction, d2, the distance between the MIG welding wire and the edge of the rib plate perpendicular to the welding direction, d3, the distance between the laser beam spot and the edge of the rib plate perpendicular to the welding direction; L1, the swing distance of the laser beam spot perpendicular to the welding direction; L2, the swing distance of the laser beam spot along the welding direction. DETAILED DESCRIPTION

[0012] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: Refer to the attached Figure 1-5 The present embodiment provides a single-side full penetration welding process for a stainless steel oblique T-shaped joint, adopts a laser-MIG composite welding method, and performs welding from the obtuse angle side of the oblique T-shaped joint; along the welding direction, the laser beam 2 is in front and the MIG arc is in the back, and the distance d1 between the laser beam 2 and the MIG welding wire 5 on the surface of the bottom plate 4 is 0-15mm; perpendicular to the welding direction, the distance d2 between the MIG welding wire 5 and the edge of the rib plate 3 is 0-3mm, and the distance d3 between the laser beam spot and the edge of the rib plate 3 is 0-2mm; the laser beam spot swings on the workpiece surface, and the swing speed is 80mm / min-300mm / min.

[0013] Refer to the attached Figure 3 and 4 Preferably, in a plane parallel to the welding direction, the angle α1 between the MIG welding gun 1 and the base plate 4 is 60°-90°, and the angle α2 between the laser beam 2 and the base plate 4 is 45°-100°; in a plane perpendicular to the welding direction, the angle α3 between the MIG welding gun 1 and the base plate 4 is 50°-80°, and the angle α4 between the laser beam 2 and the rib 3 is 60°-110°.

[0014] Refer to the attached Figure 5 Preferably, the swing shape of the laser beam spot on the workpiece surface is arbitrary, the swing distance L1 of the laser beam spot perpendicular to the welding direction is 0.2-1 mm, and the swing distance L2 of the laser beam spot along the welding direction is 0.5-3 mm.

[0015] Preferably, the laser power is 500W-6000W, the defocus is -2mm-+5mm, the MIG welding current is 100A-350A, and the welding speed is 300mm / min-2100mm / min.

[0016] Refer to the attached Figure 3 Preferably, the angle α5 between the rib plate 3 and the bottom plate 4 is in the range of 10°-50°, and the thickness of the rib plate 3 is in the range of 0.8 mm-6 mm. Example

[0017] For a certain oblique T-shaped joint, the workpiece material is austenitic stainless steel 316L, the wall thickness of the rib 3 is 1.5mm, and the angle α5 between the rib 3 and the bottom plate 4 is 25°. The specific process parameters are as follows: A laser-MIG hybrid welding method is adopted to perform welding from the obtuse angle side of the oblique T-joint; along the welding direction, the laser beam 2 is in front and the MIG arc is in the back, and the distance d1 between the laser beam 2 and the MIG welding wire 5 on the bottom plate surface is 3 mm; perpendicular to the welding direction, the distance d2 between the MIG welding wire 5 and the edge of the rib plate 3 is 2 mm, and the distance d3 between the laser beam spot and the edge of the rib plate 3 is 1 mm; the laser beam spot swings on the workpiece surface, and the swing speed is 150 mm / min.

[0018] In a plane parallel to the welding direction, the angle α1 between the MIG welding gun 1 and the base plate 4 is 80°, and the angle α2 between the laser beam 2 and the base plate 4 is 60°; in a plane perpendicular to the welding direction, the angle α3 between the MIG welding gun 1 and the base plate 4 is 60°, and the angle α4 between the laser beam 2 and the rib 3 is 90°.

[0019] The swing trajectory of the laser beam spot on the workpiece surface is circular in shape with a diameter of 1 mm, that is, L1 and L2 are both 1 mm.

[0020] The laser power is 3000W, the defocus is 0mm, the MIG welding current is 220A, and the welding speed is 1500mm / min.

[0021] Welding effect Figure 6 and Figure 7 shown. Example

[0022] For a certain oblique T-shaped joint, the workpiece material is austenitic stainless steel 304L, the wall thickness of the rib plate 3 is 1.8mm, and the angle α5 between the rib plate 3 and the bottom plate 4 is 25°. The specific process parameters are as follows: A laser-MIG hybrid welding method is adopted to perform welding from the obtuse angle side of the oblique T-shaped joint; along the welding direction, the laser beam 2 is in front and the MIG arc is in the back, and the distance d1 between the laser beam 2 and the MIG welding wire 5 on the surface of the bottom plate 4 is 5 mm; perpendicular to the welding direction, the distance d2 between the MIG welding wire 5 and the edge of the rib plate 3 is 1 mm, and the distance d3 between the laser beam spot and the edge of the rib plate 3 is 1 mm; the laser beam spot swings on the workpiece surface, and the swing speed is 200 mm / min.

[0023] In a plane parallel to the welding direction, the angle α1 between the MIG welding gun 1 and the base plate 4 is 80°, and the angle α2 between the laser beam 2 and the base plate 4 is 60°; in a plane perpendicular to the welding direction, the angle α3 between the MIG welding gun 1 and the base plate 4 is 60°, and the angle α4 between the laser beam 2 and the rib 3 is 90°.

[0024] The swing trajectory of the laser beam spot on the workpiece surface is rectangular in shape, the swing distance L1 perpendicular to the welding direction is 0.8 mm, and the swing distance L2 along the welding direction is 2 mm.

[0025] The laser power is 3500W, the defocus is -2mm, the MIG welding current is 300A, and the welding speed is 1800mm / min.

[0026] Welding effect Figure 8 and Fig. 9 shown. Example

[0027] For a certain oblique T-shaped joint, the workpiece material is austenitic stainless steel 316L, the rib wall thickness is 3mm, the angle α5 between the rib 3 and the bottom plate 4 is 15°, and the specific process parameters are as follows: A laser-MIG hybrid welding method is adopted to perform welding from the obtuse angle side of the oblique T-joint; along the welding direction, the laser beam 2 is in front and the MIG arc is in the back, and the distance d1 between the laser beam 2 and the MIG welding wire 5 on the bottom plate surface is 2 mm; perpendicular to the welding direction, the distance d2 between the MIG welding wire 5 and the edge of the rib plate 3 is 3 mm, and the distance d3 between the laser beam spot and the edge of the rib plate 3 is 2 mm; the laser beam spot swings on the workpiece surface, and the swing speed is 100 mm / min.

[0028] In a plane parallel to the welding direction, the angle α1 between the MIG welding gun 1 and the base plate 4 is 70°, and the angle α2 between the laser beam 2 and the base plate 4 is 70°; in a plane perpendicular to the welding direction, the angle α3 between the MIG welding gun 1 and the base plate 4 is 80°, and the angle α4 between the laser beam 2 and the rib 3 is 100°.

[0029] The swing trajectory of the laser beam spot on the workpiece surface is circular in shape with a diameter of 0.8 mm, that is, L1 and L2 are both 0.8 mm.

[0030] Preferably, the laser power is 4500 W, the defocus is -2 mm, the MIG welding current is 320 A, and the welding speed is 1200 mm / min. Example

[0031] For a certain oblique T-shaped joint, the workpiece material is austenitic stainless steel 304L, the wall thickness of the rib plate 3 is 5mm, and the angle α5 between the rib plate 3 and the bottom plate 4 is 40°. The specific process parameters are as follows: A laser-MIG hybrid welding method is adopted to perform welding from the obtuse angle side of the oblique T-joint; along the welding direction, the laser beam 2 is in front and the MIG arc is in the back, and the distance d1 between the laser beam 2 and the MIG welding wire 5 on the surface of the bottom plate 4 is 8 mm; perpendicular to the welding direction, the distance d2 between the MIG welding wire 5 and the edge of the rib plate 3 is 3 mm, and the distance d3 between the laser beam spot and the edge of the rib plate 3 is 1 mm; the laser beam spot swings on the workpiece surface, and the swing speed is 280 mm / min.

[0032] In a plane parallel to the welding direction, the angle α1 between the MIG welding gun 1 and the base plate 4 is 60°, and the angle α2 between the laser beam 2 and the base plate 4 is 60°; in a plane perpendicular to the welding direction, the angle α3 between the MIG welding gun 1 and the base plate 4 is 50°, and the angle α4 between the laser beam 2 and the rib 3 is 90°.

[0033] The swing trajectory of the laser beam spot on the workpiece surface is circular in shape with a diameter of 0.5 mm, that is, L1 and L2 are both 0.5 mm.

[0034] Preferably, the laser power is 5000 W, the defocus is -1 mm, the MIG welding current is 180 A, and the welding speed is 1000 mm / min. Example

[0035] For a certain oblique T-shaped joint, the workpiece material is austenitic stainless steel 316L, the wall thickness of the rib plate 3 is 1mm, and the angle α5 between the rib plate 3 and the bottom plate 4 is 10°. The specific process parameters are as follows: A laser-MIG hybrid welding method is adopted to perform welding from the obtuse angle side of the oblique T-joint; along the welding direction, the laser beam 2 is in front and the MIG arc is in the back, and the distance d1 between the laser beam 2 and the MIG welding wire 5 on the surface of the bottom plate 4 is 1 mm; perpendicular to the welding direction, the distance d2 between the MIG welding wire 5 and the edge of the rib plate 3 is 0 mm, and the distance d3 between the laser beam spot and the edge of the rib plate 3 is 0.5 mm; the laser beam spot swings on the workpiece surface, and the swinging speed is 80 mm / min.

[0036] In a plane parallel to the welding direction, the angle α1 between the MIG welding gun 1 and the base plate 4 is 60°, and the angle α2 between the laser beam 2 and the base plate 4 is 45°; in a plane perpendicular to the welding direction, the angle α3 between the MIG welding gun 1 and the base plate 4 is 50°, and the angle α4 between the laser beam 2 and the rib 3 is 60°.

[0037] The swing shape of the laser beam spot on the workpiece surface is rectangular, the swing distance L1 perpendicular to the welding direction is 1 mm, and the swing distance L2 of the laser beam spot along the welding direction is 3 mm.

[0038] Preferably, the laser power is 1500 W, the defocus is +5 mm, the MIG welding current is 100 A, and the welding speed is 1200 mm / min.

Claims

1. A single-side full penetration welding process for a stainless steel inclined T-joint, characterized in that: A laser-MIG hybrid welding method is adopted to weld from the obtuse angle side of the oblique T-shaped joint; along the welding direction, the laser beam (2) is in front and the MIG arc is in the back, and the distance d1 between the laser beam (2) and the MIG welding wire (5) on the surface of the bottom plate (4) is 0-15 mm; perpendicular to the welding direction, the distance d2 between the MIG welding wire (5) and the edge of the rib plate (3) is 0-3 mm, and the distance d3 between the laser beam spot and the edge of the rib plate (3) is 0-2 mm; the laser beam spot swings on the workpiece surface, and the swing speed is 80 mm / min-300 mm / min.

2. A single-side full penetration welding process for a stainless steel inclined T-joint according to claim 1, characterized in that: In a plane parallel to the welding direction, an included angle α1 between the MIG welding gun (1) and the bottom plate (4) is 60°-90°, and an included angle α2 between the laser beam (2) and the bottom plate (4) is 45°-100°; in a plane perpendicular to the welding direction, an included angle α3 between the MIG welding gun (1) and the bottom plate (4) is 50°-80°, and an included angle α4 between the laser beam (2) and the rib plate (3) is 60°-110°.

3. A single-side full penetration welding process for a stainless steel inclined T-joint according to claims 1 and 2, characterized in that: The swing distance L1 of the laser beam spot perpendicular to the welding direction is 0.2-1 mm, and the swing distance L2 of the laser beam spot along the welding direction is 0.5-3 mm.

4. A single-side full penetration welding process for a stainless steel inclined T-joint according to any one of claims 1 to 3, characterized in that: The laser power is 500W-6000W, the defocus is -2mm-+5mm, the MIG welding current is 100A-350A, and the welding speed is 300mm / min-2100mm / min.

5. A single-side full penetration welding process for a stainless steel inclined T-joint according to any one of claims 1 to 3, characterized in that: The included angle α5 between the rib plate (3) and the bottom plate (4) is in the range of 10°-50°, and the thickness of the rib plate (3) is in the range of 0.8 mm-6 mm.

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