CN101491856B - Large forgings compression arc and induction composite heat-source repair-welding device and method - Google Patents

Abstract

The invention discloses a large-scale forging compression arc plus induction compound heat source repair welding device and its method. The repair welding device includes a six-axis robot, an operating frame that can move up and down, back and forth, a workbench, and a welding torch; A six-axis robot is set, an inductor and a welding torch are arranged on the robot, a temperature sensor is arranged next to the inductor, and the welding torch can generate a compression arc. The repair welding method of the present invention includes the following steps: first, prepare a protective agent for repair welding and deposited metal according to the material composition of the large forging; then preset the program and related parameters; then place the protective agent on the repair welding area and Conduct induction heating on the repair welding area; collect the temperature of the repair welding area, and judge whether it reaches the preset value, if not, continue heating; remove the sensor after heating, ignite the compression arc to start welding; conduct induction after welding heating. The invention realizes the preheating before the repair welding, and the strength of the repair welding joint is greater than that of the deposited metal itself.

Description

Repair welding method of compression arc plus induction composite heat source for large forgings

technical field

The invention belongs to a special welding method for depositing surfacing welding metal on the surface of large forgings, in particular to a repair welding method for large forgings with compression arc plus induction composite heat source.

Background technique

Arc surfacing technology uses melting electrode arc, submerged arc, TIG arc, plasma arc, etc. to heat and melt metal wire, metal strip, metal powder, etc., and the molten metal is deposited on the surface of the substrate, and the surfacing layer is formed after solidification. Conventional surfacing welding methods such as melting electrode and submerged arc surfacing welding, the welding wire is automatically fed, the arc is generated between the welding wire and the base metal, and the arc melts the welding wire to form a droplet, which is deposited on the surface of the base through free, short circuit or slag wall transition. The surfacing layer is formed with high efficiency and more melting of the substrate; TIG surfacing and plasma surfacing arcs are generated between the tungsten electrode and the workpiece, and the welding wire is fed under the arc flashing area to be heated and melted and dripped onto the surface of the substrate, forming after solidification Overlay.

Large-scale forgings generally weigh tens to hundreds of kilograms, the repair welding area is generally small, and the overall heat input is not large. Rapid heating and rapid cooling of surfacing welding can easily cause cold cracks in the welded joints of forgings. Large-scale forgings have large volume and large heat capacity. Fast heat dissipation, using conventional surfacing welding process, forgings are prone to non-fusion defects, so avoiding cracks and non-fusion defects is one of the main difficulties in repair welding of large forgings. At present, there is no research report on the deposition welding process method of automatic compression arc + induction composite heat source to prefabricate and preset repair welding materials for large forgings.

Contents of the invention

The object of the present invention is to provide a deposition welding method for prefabricating and presetting repairing welding materials with automatic compression arc plus induction composite heat source for large forgings.

The technical solution to realize the object of the present invention is: a large-scale forging compression arc plus induction composite heat source repair welding device, including a six-axis robot, an operating frame that can move up and down, back and forth, a workbench, and a welding torch; A six-axis robot is equipped with an inductor and a welding torch, a temperature sensor is arranged next to the sensor, and the welding torch can generate a compressed arc.

The repair welding method of the compression arc plus induction composite heat source repair welding device for large forgings comprises the following steps:

Step 1. Prepare a protective agent for repair welding according to the material composition of the large forging; prepare a deposited metal for repair welding according to the size and shape of the repair welding area;

Step 2. Preset the robot controller program and compression arc parameters; the preset control program includes: induction heating program, sensor running track, arc running track, welding torch posture, welding process program;

Step 3. Put the protective agent on the repair welding area;

Step 4. Inductively heat the repair welding area; control the sensor through a six-axis robot to inductively heat the repair welding area according to the preset induction heating program and running track;

Step 5. Collect the temperature of the repaired welding area, and judge whether the temperature of the repaired welding area reaches the preset value. If it reaches the preset value, perform step 6, otherwise continue heating;

Step 6. Remove the sensor, preset the repair welding deposited metal in the repair welding area, move the welding torch to the position of the repair welding deposited metal, and ignite the compression arc parameters and welding process parameters preset in step 2. arc, and then start welding according to the trajectory of the arc and the posture of the welding torch preset in step 2;

Step 7. Use the current sensor and the voltage sensor to collect the current and voltage values of the welding process, measure and control the welding parameters through the welding process program stored in the controller, decrease the current to stop the arc, end the welding torch motion program, and remove the welding torch;

Step 8. Inductively heat the repair welding area, decrease the power of the induction heat source, and remove the inductor;

Step 9: Carry out extrusion molding modification to the forging after the repair welding, and end the repair welding.

Compared with the prior art, the present invention has significant advantages: 1), adopts composite heat source, improves the temperature field of the forging before repair welding, and realizes preheating before repair welding; 2), can repair welding according to needs The shape and size of the area and the composition of the forging are prefabricated by powder pre-pressing method to ensure the shape, size and composition, and the adjustment of composition and performance is very easy; Compress the energy density of the arc to obtain high-quality joints; 4) Using a composite heat source, post-heat treatment can be performed after welding to adjust the cooling rate to obtain the required structure; 5) The strength of the repair welding joint is greater than the strength of the deposited metal itself.

Description of drawings

Fig. 1 is a structural schematic diagram of a large-scale forging compression arc plus induction composite heat source repair welding device of the present invention.

Fig. 2 is a flow chart of the method for repairing welding of large forgings with compression arc plus induction composite heat source according to the present invention.

Fig. 3 is a schematic diagram of the structure of the compression arc nozzle of the compression arc plus induction composite heat source repair welding device for large forgings of the present invention.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings.

Referring to Fig. 1, a large-scale forging compression arc plus induction compound heat source repair welding device of the present invention includes a six-axis robot 1, a welding torch 2, an operating frame 5 that can move up and down, back and forth, a welding system 6, a robot controller 7, and a workbench 8. A temperature sensor 9; a six-axis robot 1 is set on the operating frame 5, a sensor 2-2 and a welding torch 2 are set on the robot, a temperature sensor 9 is set next to the sensor 2-2, and a tungsten electrode 2 is set in the welding torch 2 -3 and nozzle 2-4, tungsten electrode 2-3 and nozzle 2-4 can generate compression arc 2-1.

Before repair welding, design and manufacture repair welding deposited metal 4 and protective agent 4-1 according to the material and size of large forgings 3, adjust the parameters of compression arc 2-1, design compression arc motion trajectory and welding torch attitude program, and design composite induction heat source motion program , and store relevant data in the robot controller 7. When repairing welding, first place the protective agent 4-1 in the repairing welding area, and the sensor 2-2 controlled by the six-axis robot 1 will inductively heat the repairing welding area according to the preset trajectory, the temperature sensor 9 will work, and the detection temperature will meet the requirements value, the 6-axis robot 1 moves and removes the sensor 2-2; at the same time, the repair welding deposited metal 4 is preset, and the compression arc 2-1 is generated between the tungsten electrode 2-3 and the nozzle 2-4, and the welding torch 2 drives the compression The arc 2-1 moves with the 6-axis robot 1 and the operating frame 5, moves the welding torch 2 to the position of the repair welding deposited metal 4, and starts welding; after the welding torch moves, the arc is extinguished and the welding torch is removed by the 6-axis robot 1, and Move the inductor 2-2 into the repair welding area, carry out heating movement, and gradually reduce the heating power, and remove the inductor 2.

In conjunction with Fig. 2, the large-scale forging compression arc plus induction compound heat source repair welding method of the present invention comprises the following steps:

Step 1. Prepare a protective agent for repair welding according to the material composition of the large forging; prepare a deposited metal for repair welding according to the size and shape of the repair welding area;

Step 2. Preset the robot controller program and compression arc parameters; the preset content includes: induction heating program, sensor running track, arc running track, welding torch posture, welding process program; compression arc parameters can be set to The diameter of the nozzle hole is 2 mm, the first compression angle α ₁ is 100°, the second compression angle α ₂ is 90°, the radius R is 25 mm, the length h of the first nozzle hole is 2 mm, and the length h ₁ of the second nozzle hole is 1.5 mm , The third nozzle hole length h ₂ is 1.5mm.

Step 3. Put the protective agent on the repair welding area;

Step 4. Inductively heat the repair welding area; control the sensor through a six-axis robot to inductively heat the repair welding area according to the preset induction heating program and running track;

Step 5. Collect the temperature of the repaired welding area, and judge whether the temperature of the repaired welding area reaches the preset value. If it reaches the preset value, perform step 6, otherwise continue heating;

Step 6. Remove the sensor, preset the repair welding deposited metal in the repair welding area, move the welding torch to the position of the repair welding deposited metal, and ignite the compression arc parameters and welding process parameters preset in step 2. Arc, and then start welding according to the trajectory of the arc and the posture of the welding torch preset in step 2; during the welding process, the welding torch drives the compressed arc to move to a distance of 0.3-0.8mm from the edge of the large forging and stay for 0.2-2 seconds.

Step 7. Use the current sensor and the voltage sensor to collect the current and voltage values of the welding process, measure and control the welding parameters through the welding process program stored in the controller, decrease the current to stop the arc, end the welding torch motion program, and remove the welding torch;

Step 8. Inductively heat the repair welding area, decrease the power of the induction heat source, and remove the inductor;

Step 9: Carry out extrusion molding modification to the forging after the repair welding, and end the repair welding.

The particle size of the protective agent in the above step 1 is 60-180 mesh. The protective agent can protect the large forgings from oxidation during the induction heating process, and at the same time protect the molten pool produced by the melting of the repair welding deposited metal from being oxidized. The deposited metal is prepared by powder pre-pressing method, and its alloy composition is roughly the same as that of large forgings. The carbon content is 10-40% lower than that of large forgings, and the carbon equivalent is 20-50% lower. The compression arc parameters can change the diameter and length of the plasma channel according to the material, shape, thickness and forging size of the repair welding material, adjust the energy density of the compression arc, and obtain high-quality forging repair welding joints.

Below in conjunction with embodiment, the present invention is further described.

Take 1500mm diameter 40Cr disc-shaped end face repair welding Φ60mm deep 3mm forging as an example. According to the shape and size of the repair welding area Φ60mm deep 3mm and 40Cr material, iron powder and Cr powder are used to form medium-carbon and Cr-containing repair welding deposits, and the carbon content is controlled at 0.25-0.3%, and pressed into Φ59.8mm and 3.3mm high. For unsintered powder metallurgy blocks, a protective agent (J05-2) capable of removing Cr, Fe, Si, and Mn elements is selected, and the mesh number is 120.

Put 20g of the protective agent (J05-2) into the area to be repaired, set the circular sensor Φ40mm, make a circular motion, and the trajectory diameter Φ54mm, set the welding gun 2 repair welding movement as the trajectory of the arc motion, divided into 12 linear movements, the swing range is 2mm, and the data is stored in the system controller 7 .

Design compression arc 2-1 parameter, in conjunction with Fig. 3, arc parameter of the present invention can be: nozzle aperture 2mm, the first compression angle α ₁ is 100 °, the second compression angle α ₂ angle is 90 °, radius R is 25mm, The length h of the first nozzle hole is 2 mm, the length h ₁ of the second nozzle hole is 1.5 mm, and the length h ₂ of the third nozzle hole is 1.5 mm.

The sensor 2-2 controlled by the 6-axis robot 1 of the patented device performs a circular motion with a track diameter of Φ54mm according to the size of Φ59.8mm and a circular shape, and the temperature detector 9 detects that the temperature in the repair welding area of the forging 3 reaches 180-200 ℃, stop induction heating; ignite the compression arc 2-1 between the tungsten electrode 2-3 of the welding torch 2 and the nozzle 2-4, the welding torch 2 drives the compression arc 2-1 to move with the 6-axis robot 1 and the operating frame 5, and the The welding torch 2 moves to the center of the repair welding deposited metal 4 and starts welding. The arc moves with the operation frame 5 and the six-axis robot 1, and its trajectory and posture are based on the size, shape and position of the repair welding area and the repair welding deposited metal 4. It is determined in advance, that is, according to 12 linear movements, the swing range is 2mm, when the welding torch moves to the repair welding round edge, keep the distance between the welding torch and the edge at 0.5mm, stay for 0.3s, welding current 220-230A, arc voltage 23-23.5V, welding speed 15cm/min, after welding, remove the welding torch 2, start induction heating, the sensor 2-2 will make a circular motion of Φ54mm under the drive of the six-axis robot 1, and its maximum power is 2/3 of the preheating power, induction heating After 30 seconds, gradually reduce the compound induction heating power, and turn off the compound induction heating power after 30 seconds.

Claims (2)

1. A method for repairing welding of large forgings with compression arc plus induction composite heat source, wherein the repair welding device for large forgings with compression arc plus induction composite heat source includes a six-axis robot [1] and an operating frame that can move up and down and back and forth [5] ], a workbench [8] and a welding torch [2], a six-axis robot [1] is set on the operating frame [5], and a sensor [2-2] and a welding torch [2] are set on the robot, and the sensor [ 2-2] a temperature sensor [9] is set next to it, and the welding torch [2] can generate a compression arc [2-1]. It is characterized in that the method includes the following steps: Step 1. Prepare a protective agent for repair welding according to the material composition of the large forging; prepare a deposited metal for repair welding according to the size and shape of the repair welding area; Step 2. Preset the robot controller program and compression arc parameters. The preset contents include: induction heating program, sensor running track, arc running track, welding torch posture, welding process program, and compression arc parameters; Step 3. Put the protective agent on the repair welding area; Step 4. Inductively heat the repair welding area; control the sensor through a six-axis robot to inductively heat the repair welding area according to the preset induction heating program and running track; Step 5. Collect the temperature of the repaired welding area, and judge whether the temperature of the repaired welding area reaches the preset value. If it reaches the preset value, perform step 6, otherwise continue heating; Step 6. Remove the sensor, preset the repair welding deposited metal in the repair welding area, move the welding torch to the position of the repair welding deposited metal, and ignite the compression arc parameters and welding process parameters preset in step 2. arc, and then start welding according to the trajectory of the arc and the posture of the welding torch preset in step 2; Step 7. Use the current sensor and the voltage sensor to collect the current and voltage values of the welding process, measure and control the welding parameters through the welding process program stored in the controller, decrease the current to stop the arc, end the welding torch motion program, and remove the welding torch; Step 8. Inductively heat the repair welding area, decrease the power of the induction heat source, and remove the inductor; Step 9: Carry out extrusion molding modification to the forging after the repair welding, and end the repair welding. 2. The welding repair method according to claim 1, characterized in that the particle size of the protective agent in step 1 is 60-180 mesh.

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