Power plant reducer sleeve type local laser welding method

Abstract

The application discloses a power plant reducer sleeve type local laser welding method, comprising the following steps: S1, machining a welding groove on the welding surface of a reducer steel pipe to be welded, and then performing laser cleaning to make the welding surface smooth and clean; S2, processing a welding wire into a sleeve shape with a thickness of 0.2mm-0.6mm, and sleeving the welding wire on the steel pipe to tightly adhere to the welding surface; S3, placing annular induction heaters on both sides of the welding groove respectively, and performing preheating before welding, with a preheating temperature of 200 DEG C-300 DEG C; and S4, performing three-stage welding on the assembled welding component without filling the welding wire by means of a wind-cooled handheld optical fiber laser, and then performing laser swing filling surface welding. The power plant reducer sleeve type local laser welding method solves the technical problem that excessive heat input in the prior art results in large welding deformation and large residual stress.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of welding, in particular to a sleeve type local laser welding method for a reducer of a power plant. BACKGROUND

[0002] The reducer is an important component of the steam-water pipeline of a power plant boiler, and traditional welding methods include manual arc welding and tungsten inert gas welding, etc. The slope size of the traditional arc welding is large due to the size limitation of the welding gun. After welding, the overall heat input is large, which leads to a large welding heat affected zone, high welding deformation and high residual stress.

[0003] In view of the problem of large welding deformation and high residual stress caused by excessive heat input in the welding process of the reducer, a sleeve type local laser welding method for the reducer of the power plant is provided. SUMMARY

[0004] The purpose of the present application is to provide a sleeve type local laser welding method for the reducer of the power plant to solve the technical problem of large welding deformation and high residual stress caused by excessive heat input in the prior art.

[0005] To achieve the above purpose, the present application provides a sleeve type local laser welding method for the reducer of the power plant, comprising the following steps:

[0006] S1, machining a welding slope on the welding surface of the reducer steel pipe to be welded, and then performing laser cleaning to make the welding surface smooth and clean;

[0007] S2, processing the welding wire into a sleeve shape with a thickness of 0.2mm-0.6mm, and sleeving the welding wire on the steel pipe to tightly fit the welding surface;

[0008] S3, placing a ring-shaped induction heater on both sides of the welding slope for preheating before welding, and the preheating temperature is 200℃-300℃;

[0009] S4, performing three-stage welding on the assembled welding components without filling the wire first, and then performing laser swing filling surface welding by using a air-cooled handheld optical fiber laser.

[0010] Further, the reducer steel pipe in S1 is divided into steel pipe one and steel pipe two, the wall thickness of the steel pipe one and the steel pipe two is 4mm-12mm, the outer diameter is 45mm-80mm, the welding slope adopts V-shaped slope, and the upper width of the V-shaped slope is 0.8-1.2mm.

[0011] Further, the workpiece to be welded in S1 is cleaned by the air-cooled handheld optical fiber laser to remove the oil stains and oxidation film on the surface of the workpiece to be welded.

[0012] Further, the welding wire in S2 is processed into a sleeve shape by a specific mold, and the processed sleeve is sleeved on the welding surface of the steel pipe, and the welding wire serves as an intermediate layer between the steel pipe one and the steel pipe two.

[0013] Further, in S3, the temperature is kept constant after preheating before welding until the end of the welding process.

[0014] Further, in S4, the air-cooled handheld laser in the three-stage welding process has a laser power of 1500W, 1250W and 1000W respectively, and one circle of welding is completed for each laser power, and a total of three circles; after the three-stage welding is completed, the weld is cleaned by laser to remove the oxide skin and oil stains on the welding surface, so as to ensure that the welding surface is smooth and clean.

[0015] Further, in the laser swing wire filling cover welding, the laser power is 1200W-1500W, and the laser swing amplitude is 1.2mm-2mm.

[0016] Based on the above technical scheme, the present application can produce the following beneficial effects:

[0017] The sleeve type local laser welding method for the reducer pipe of the power plant provided by the present application makes the welding wire into a sleeve shape, matches it with the reducer pipe to be welded, and tightly adheres to the welding surface; the sleeve-shaped welding wire is fully melted and combined with the reducer pipe by the three-stage laser welding method, which reduces the filling amount of the welding wire, reduces the overall heat input, greatly reduces the welding deformation and residual stress. Finally, the laser swing wire filling cover welding is carried out, the heat input is more uniform through the laser beam swing, and the molten pool has a certain stirring effect, which can ensure the stability of the molten pool flow, has a great effect on maintaining the stability of the welding process and reducing pores, prevents the weld from having defects such as undercut, and improves the welding quality. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a structural schematic diagram of an embodiment of the present application;

[0019] 1, steel pipe one; 2, annular induction heater; 3, V-shaped groove; 4, steel pipe two; 5, welding wire. DETAILED DESCRIPTION

[0020] In order to better understand the purpose, structure and function of the present application, the following will describe the sleeve type local laser welding method for the reducer pipe of the power plant in combination with the drawings.

[0021] In the description of the present application, it should be noted that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0022] The present application provides a power plant reducer sleeve type local laser welding method, comprising the following steps:

[0023] S1, the welding surface of the reducer steel pipe to be welded is machined to form a welding groove, and then laser cleaning is performed to make the welding surface smooth and clean;

[0024] S2, the welding wire 5 is processed into a sleeve shape with a thickness of 0.2mm-0.6mm, and the welding wire 5 is sleeved on the steel pipe and tightly fitted with the welding surface;

[0025] S3, an annular induction heater 2 is placed on both sides of the welding groove for preheating before welding, and the preheating temperature is 200-300℃;

[0026] S4, the assembled welding components are first welded without filling wire by a air-cooled handheld optical fiber laser, and then laser oscillation filling surface welding is performed.

[0027] Further, the reducer steel pipe in S1 is divided into steel pipe one 1 and steel pipe two 4, the wall thickness of the reducer steel pipe of steel pipe one 1 and steel pipe two 4 is 4-12mm, the outer diameter is 45-80mm, the welding groove adopts V-shaped groove 3, and the upper width of the V-shaped groove 3 is 0.8-1.2mm.

[0028] Further, the laser cleaning of the workpiece to be welded in S1 is performed by a air-cooled handheld optical fiber laser, and the oil stains and oxide film on the surface of the workpiece to be welded are removed.

[0029] Further, the welding wire in S2 is processed into a sleeve shape by a special mold, and the processed sleeve is inserted into the welding surface of the steel pipe, and the welding wire serves as an intermediate layer between steel pipe one 1 and steel pipe two 4.

[0030] Further, in S3, the preheating before welding is kept at a constant temperature until the end of the welding process.

[0031] Further, in the third stage welding process in S4, the air-cooled handheld laser has a laser power of 1500W, 1250W and 1000W respectively, and one circle of welding is completed for each laser power, and a total of three circles; after the third stage welding is completed, laser cleaning is performed on the weld to remove the oxide skin and oil stains on the welding surface, so as to ensure that the welding surface is smooth and clean.

[0032] Further, in the laser swing wire filling surface welding, the laser power is 1200W-1500W, and the laser swing amplitude is 1.2mm-2mm.

[0033] The power plant reducing pipe sleeve type local laser welding method provided by the application sleeves the welding wire 5 in a sleeve shape, matches it with the reducing pipe to be welded, and tightly adheres to the welding surface; the sleeve-shaped welding wire 5 is fully melted and combined with the reducing pipe by the three-stage laser welding method, the filling amount of the welding wire 5 is reduced, the overall heat input is reduced, and the welding deformation and residual stress are greatly reduced. Finally, laser swing wire filling surface welding is performed, the heat input is more uniform through the laser beam swing, and the molten pool has a certain stirring effect, which can ensure the stability of the molten pool flow, has a great effect on maintaining the stability of the welding process and reducing pores, prevents the weld from having defects such as undercut, and improves the welding quality.

[0034] It can be understood that the application is described by some embodiments, and those skilled in the art know that various changes or equivalent replacements can be made to the features and embodiments without departing from the spirit and scope of the application. In addition, under the guidance of the application, the features and embodiments can be modified to adapt to specific conditions and materials without departing from the spirit and scope of the application. Therefore, the application is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of the application are within the scope of the application.

Claims

1. A method of partial laser welding of a reducer sleeve for a power plant, characterized in that, It comprises the following steps: S1, the welding surface of the pipe of different diameters to be welded is processed to form a welding groove, and then laser cleaning is performed to make the welding surface smooth and clean; S2, the welding wire (5) is processed into a sleeve shape with a thickness of 0.2mm-0.6mm, and the welding wire (5) is sleeved on the steel pipe and tightly attached to the welding surface; S3, an annular induction heater (2) is placed on both sides of the welding groove for preheating before welding, and the preheating temperature is 200-300℃; S4, the assembled welding components are first welded without filling wire by a wind-cooled handheld optical fiber laser, and then laser oscillation filling wire is used for surface welding; The pipe of different diameters in S1 is divided into steel pipe one (1) and steel pipe two (4), the wall thickness of steel pipe one (1) and steel pipe two (4) is 4-12mm, the outer diameter is 45-80mm, the welding groove adopts V-shaped groove (3), the upper width of V-shaped groove (3) is 0.8-1.2mm; The welding wire (5) in S2 is processed into a sleeve shape by a special mold, and the processed sleeve is inserted into the welding surface of the steel pipe, and the welding wire (5) serves as an intermediate layer between steel pipe one (1) and steel pipe two (4); In S4, the wind-cooled handheld laser in the three-stage welding process has laser power of 1500W, 1250W and 1000W respectively, each laser power completes one circle of welding, and a total of three circles; after three-stage welding, the weld is cleaned by laser to remove the oxide skin and oil stains on the welding surface, so as to ensure the smoothness of the welding surface.

2. A method of partial laser welding of a reducer sleeve for a power plant according to claim 1, characterized in that, In S1, the wind-cooled handheld optical fiber laser is used for laser cleaning of the welding workpiece to remove the oil stains and oxide film on the surface of the welding workpiece.

3. The method of claim 1, wherein, In S3, the preheating before welding is kept at a constant temperature until the end of the welding process.

4. The method of claim 1, wherein, In the laser oscillation filling wire surface welding, the laser power is 1200-1500W, and the laser oscillation amplitude is 1.2-2mm.

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