Welding method of carbon steel continuous pipe butt dissimilar metal 20crmo tool barrel

Abstract

The application discloses a welding method for butt-jointing dissimilar metals of carbon steel continuous pipes and 20CrMo tool barrels, and steps include: step 1, annealing the tool barrel; step 2, straightening, cutting and fixing the continuous pipe; step 3, cleaning the inner and outer surfaces of the butt joint, and machining the groove; step 4, pipe end assembling, positioning and welding; step 5, clamping the cooling block and the heat preservation cotton; step 6, welding; and step 7, weld treatment. According to the situation in the well, the method can preset multiple gas lift tool positions in advance, and weld and fix the positions, so that the oilfield customers can be provided with a continuous pipe and tool welding integrated product, the original continuous pipe gas lift operation process of the oilfield is improved, the continuous pipe can be put into the well at one time, segmented gas lift at the designed position of the continuous pipe can be realized, the wellhead pressure is reduced, the liquid discharge capacity is increased, and the gas lift operation construction cost is reduced.

Description

Technical Field

[0001] This invention belongs to the field of welding technology and relates to a welding method for butt welding of carbon steel continuous pipe to dissimilar metal 20CrMo tool cylinder. Background Technology

[0002] Coiled tubing (CT), also known as flexible tubing, serpentine tubing, or coiled tubing, is a type of high-strength, highly ductile continuous welded steel pipe produced using special micro-alloy materials and unique manufacturing processes. A single pipe can reach tens of thousands of meters in length. The finished product is transported and delivered on a drum. It is mainly used in oil and gas field well workover, logging, drilling, completion, and oil and gas transportation operations.

[0003] There are two existing methods for gas lift operations using coiled tubing: one involves injecting gas through the annulus between the coiled tubing and the production tubing to lift the production fluid from the coiled tubing to the surface; the other involves injecting gas through the coiled tubing to lift the production fluid from the annulus between the coiled tubing and the production tubing to the surface. Both methods involve running the coiled tubing below the hydrostatic level in the well, requiring multiple runs and single-stage gas lifts, which suffer from long operation times, high operating costs, and increased coiled tubing fatigue. Multi-stage gas lift technology, on the other hand, involves designing and welding gas lift tools at multiple locations on a single coiled tubing reel for gas lift operations. By welding and fixing the gas lift tools in sections, the "coiled tubing + tool" integrated product can be directly run into the well for application, enabling multi-stage gas lift operations in a single run-in. This solves many problems associated with current single-stage gas lift operations, such as long operation times and high wellhead pressure.

[0004] When delivering coiled tubing products to customers, there should be no circumferential welds in the middle of the entire coil. This is because during the use of coiled tubing, it must withstand the harsh tests of tensile, compressive, bending, and corrosive environments, which places extremely stringent requirements on the welds. Conventional welding methods are difficult to meet these requirements. Summary of the Invention

[0005] The purpose of this invention is to provide a welding method for connecting carbon steel continuous tubing to a dissimilar metal 20CrMo tool barrel, which solves the problems of existing technologies such as long operation time, high wellhead pressure, and high processing and manufacturing difficulty in single-stage gas lift operations, and the inability of conventional welding methods to meet the requirements.

[0006] The technical solution adopted in this invention is a welding method for butt welding of carbon steel continuous pipe to a dissimilar metal 20CrMo tool cylinder, which is implemented according to the following steps:

[0007] Step 1: Anneal the tool holder;

[0008] Step 2: Straighten, cut, and fix the continuous tube;

[0009] Step 3: Clean and bevel the inner and outer surfaces of the rim;

[0010] Step 4: Perform pipe end assembly and positioning welding;

[0011] Step 5: Clamp the cooling block and insulation cotton;

[0012] Step 6, welding;

[0013] Step 7, weld treatment.

[0014] The beneficial effects of this invention are that the method of this invention can pre-set multiple gas lift tool positions according to the well conditions and weld them in place, which can provide oilfield customers with an integrated product of "coiled tubing + tools", improve the original coiled tubing gas lift operation process in oilfields, and enable the entire coiled tubing to be lowered into the well at one time, realize segmented gas lift at the designed position of the coiled tubing, reduce wellhead pressure, increase fluid discharge, and reduce the construction cost of gas lift operation. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the workpiece preset position during welding according to the method of the present invention;

[0016] Figure 2 This is a flowchart of the welding process of the method of the present invention;

[0017] Figure 3 This is a radiographic image of Embodiment 1 of the present invention;

[0018] Figure 4 This is a second X-ray inspection photograph of Embodiment 1 of the present invention;

[0019] Figure 5 This is a radiographic image of Embodiment 2 of the present invention;

[0020] Figure 6 This is the second X-ray inspection photograph of Embodiment 2 of the present invention;

[0021] Figure 7 This is a radiographic image of embodiment 3 of the present invention;

[0022] Figure 8 This is the second X-ray inspection photograph of Embodiment 3 of the present invention;

[0023] Figure 9 This is a radiographic image of embodiment 4 of the present invention;

[0024] Figure 10 This is the second X-ray inspection photograph of Embodiment 4 of the present invention.

[0025] In the diagram, 1 is a continuous tube, and 2 is a tool cylinder. Detailed Implementation

[0026] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0027] Reference Figure 1 In the implementation of the welding method of the present invention, the continuous tube 1 and the tool cylinder 2 are connected end to end in sequence. The material of the continuous tube 1 is CT80 grade carbon steel, and the material of the tool cylinder 2 is dissimilar metal 20CrMo. The weld requirements at the joint of the continuous tube 1 and the tool cylinder 2 are quite demanding, and conventional welding methods are difficult to meet the requirements. Therefore, the welding method of the present invention is required.

[0028] Reference Figure 2 The welding method of the carbon steel continuous tube to the dissimilar metal 20CrMo tool cylinder of the present invention mainly includes the following steps: annealing the tool cylinder 2, straightening the continuous tube 1 at the predetermined welding position, cutting at the predetermined position, grinding and beveling the tube end, assembling and positioning welding, water cooling of the continuous tube end and heat preservation of the tool cylinder end, welding, grinding of the outer weld, radiographic inspection, and delivery to the customer after passing the inspection. Specifically, the method is implemented according to the following steps:

[0029] Step 1: Anneal the tool cylinder 2;

[0030] Before welding, the tool tube 2 made of 20CrMo material is annealed to reduce the material strength of the tool tube 2 so that it matches the strength of the continuous tube 1 made of CT80 material.

[0031] Step 2: Straighten, cut, and fix the continuous tube 1;

[0032] First, use straightening equipment to straighten the continuous tube 1 (oil pipe) within a 3-meter range at the predetermined pipe end. After straightening, the straightness B of the continuous tube 1 within 1.5m should be less than 2mm. Then, use pipe cutting equipment to cut the continuous tube 1.

[0033] Step 3: Clean and bevel the inner and outer surfaces of the rim;

[0034] First, use an internal grinder and an angle grinder to clean the oil stains within 15mm of the inner surface and 25mm of the outer surface of the joint of the continuous tube 1 and the tool cylinder 2 until the tube ends of the continuous tube 1 and the tool cylinder 2 are exposed with a metallic luster; the internal grinder uses an 80-100 mesh internal grinder head and the angle grinder uses a 120-150 mesh angle grinder disc.

[0035] Then, a mechanical beveling machine is used to bevele the joint ends of the continuous pipe 1 and the tool cylinder 2 respectively, and the beveling angle of the processed pipe is 37°.

[0036] Step 4: Perform pipe end assembly and positioning welding;

[0037] Clamp the continuous pipe 1 end and the tool cylinder 2 end to be welded on the welding assembly stand, adjust the positions of the two opposite ends to make the pipe ends aligned and the assembly gap 2.2-2.5mm, and use a ruler and level to measure in the vertical and horizontal directions of the pipe ends to ensure that the continuous pipe 1 and tool cylinder 2 are aligned without misalignment, and position and weld at the 3, 9 and 12 o'clock positions of the weld seam respectively.

[0038] Step 5: Clamp the cooling block and insulation cotton;

[0039] At one end of the continuous pipe 1 that needs to be welded, a water-cooled copper block is clamped 10-15mm away from the welding bevel; at one end of the tool cylinder 2 that needs to be welded, a heat-insulating cotton is clamped 10-15mm away from the welding bevel.

[0040] Step 6, welding;

[0041] First, manual tungsten inert gas welding is used, and the welding position is 5G all-position welding. Three-point positioning welding is performed at the 12 o'clock, 3 o'clock and 9 o'clock positions of the weld.

[0042] Then, a two-layer, multi-segment welding method is adopted, with a root pass welding current of 65A and a cover pass welding current of 80A. The tool cylinder 2 is kept warm for 5 minutes.

[0043] Then, use a wire brush to clean the spaces between the layers until the metallic luster is exposed;

[0044] Step 7, weld treatment;

[0045] After completing the cover welding, remove the water-cooled copper block. First, use an 80-100 grit elastic grinding disc for rough grinding, and then use a 120-150 grit elastic grinding disc for fine grinding. Grind the weld seam until it is flush with the base material. The grinding direction is parallel to the axial direction of the pipe body.

[0046] The next step is to perform radiographic testing on the weld seams of the finished product, in accordance with the standard Q / SY BG 1023-2022.

[0047] Example 1

[0048] The material of continuous tube 1 is CT80 grade carbon steel, and the material of tool cylinder 2 is dissimilar metal 20CrMo. The procedure is as follows:

[0049] Step 1: Anneal the 20CrMo tool holder;

[0050] Annealing is performed on the 20CrMo tool cylinder before welding to improve various structural defects and residual stress caused during the welding process.

[0051] Step 2: Straighten the pipe ends, cut the pipe, and fix it.

[0052] First, use straightening equipment to complete the straightening operation within 3 meters of the predetermined position of the continuous tube 1 (oil pipe). After straightening, the straightness B of the continuous tube 1 within 1.5m is required to be less than 2mm.

[0053] Next, cut the continuous tube 1 and place the cut continuous tube 1 and tool cylinder 2 on the welding assembly stand and fix them securely.

[0054] Step 3: Surface cleaning and beveling;

[0055] First, use an internal grinder and an angle grinder to clean the oil stains within 15mm of the inner surface and 25mm of the outer surface of the joint between the continuous tube 1 and the tool cylinder 2 until the tube ends of the continuous tube 1 and the tool cylinder 2 are exposed with a metallic luster; the internal grinder uses an 80-mesh internal grinder head and the angle grinder uses a 120-mesh angle grinder disc.

[0056] Then, a mechanical beveling machine is used to bevele the joint ends of the continuous pipe 1 and the tool cylinder 2 respectively, and the beveling angle of the processed pipe is 37°.

[0057] Step 4: Perform pipe end assembly;

[0058] Clamp the continuous pipe 1 end and the tool cylinder 2 end to be welded on the welding assembly stand, adjust the positions of the two opposite ends to make the pipe ends aligned and the assembly gap 2.2mm, and use a ruler and level to measure in the vertical and horizontal directions of the pipe ends to ensure that there are no misalignments in the assembly of continuous pipe 1 and tool cylinder 2.

[0059] Step 5: Clamp the cooling block and insulation cotton;

[0060] At one end of the continuous pipe 1 that needs to be welded, a water-cooled copper block is clamped 10mm away from the welding bevel; at one end of the tool cylinder 2 that needs to be welded, a heat-insulating cotton is clamped 10mm away from the welding bevel.

[0061] Step 6: Perform welding;

[0062] First, manual tungsten inert gas welding is used, and the welding position is 5G all-position welding. Three-point positioning welding is performed at the 12 o'clock, 3 o'clock and 9 o'clock positions of the weld.

[0063] Then, a two-layer multi-segment welding method is adopted, with a root pass welding current of 65A and a cover pass welding current of 80A. After welding, the tool cylinder 2 is kept warm for 5 minutes.

[0064] Then use a wire brush to clean the spaces between the layers until the metallic luster is exposed;

[0065] Step 7, weld treatment;

[0066] After completing the cover welding, remove the water-cooled copper block, first use an 80-grit elastic grinding disc for rough grinding, then use a 120-grit elastic grinding disc for fine grinding, and grind the weld seam until it is flush with the base material. The grinding direction is parallel to the pipe axis.

[0067] Radiographic testing shall be performed on the weld seams of the finished product, in accordance with the standard Q / SY BG 1023-2022.

[0068] The relevant data and test results of Example 1 are shown in Table 1.

[0069] Example 2

[0070] The material of continuous tube 1 is CT80 grade carbon steel, and the material of tool cylinder 2 is dissimilar metal 20CrMo. The procedure is as follows:

[0071] Step 1: Anneal the 20CrMo tool holder;

[0072] Annealing is performed on the 20CrMo tool cylinder before welding to improve various structural defects and residual stress caused during the welding process.

[0073] Step 2: Straighten the pipe ends, cut the pipe, and fix it.

[0074] First, use straightening equipment to complete the straightening operation within 3 meters of the predetermined position of the continuous tube 1 (oil pipe). After straightening, the straightness B of the continuous tube 1 within 1.5m is required to be less than 2mm.

[0075] Next, cut the continuous tube 1 and place the cut continuous tube 1 and tool cylinder 2 on the welding assembly stand and fix them securely.

[0076] Step 3: Surface cleaning and beveling;

[0077] First, use an internal grinder and an angle grinder to clean the oil stains within 15mm of the inner surface and 25mm of the outer surface of the joint between the continuous tube 1 and the tool cylinder 2 until the ends of the continuous tube 1 and the tool cylinder 2 are exposed with a metallic luster; the internal grinder uses a 100-grit internal grinder head and the angle grinder uses a 150-grit angle grinder disc.

[0078] Then, a mechanical beveling machine is used to bevele the joint ends of the continuous pipe 1 and the tool cylinder 2 respectively, and the beveling angle of the processed pipe is 37°.

[0079] Step 4: Perform pipe end assembly;

[0080] Clamp the continuous pipe 1 end and the tool cylinder 2 end to be welded on the welding assembly stand, adjust the position of the two opposite ends to make the pipe ends aligned and the assembly gap 2.5mm, and use a ruler and level to measure in the vertical and horizontal directions of the pipe ends to ensure that there are no misalignments between the continuous pipe 1 and the tool cylinder 2.

[0081] Step 5: Clamp the cooling block and insulation cotton;

[0082] At one end of the continuous pipe 1 that needs to be welded, a water-cooled copper block is clamped 15mm away from the welding bevel; at one end of the tool cylinder 2 that needs to be welded, a heat-insulating cotton is clamped 15mm away from the welding bevel.

[0083] Step 6, welding;

[0084] First, manual tungsten inert gas welding is used, and the welding position is 5G all-position welding. Three-point positioning welding is performed at the 12 o'clock, 3 o'clock and 9 o'clock positions of the weld.

[0085] Then, a two-layer multi-segment welding method is adopted, with a root pass welding current of 65A and a cover pass welding current of 80A. After welding, the tool cylinder 2 is kept warm for 5 minutes.

[0086] Then use a wire brush to clean the spaces between the layers until the metallic luster is exposed;

[0087] Step 7, weld treatment;

[0088] After completing the cover welding, remove the water-cooled copper block, first use a 100-grit elastic grinding disc for rough grinding, then use a 150-grit elastic grinding disc for fine grinding, and grind the weld seam until it is flush with the base material. The grinding direction is parallel to the pipe axis.

[0089] Radiographic testing shall be performed on the weld seams of the finished product, in accordance with the standard Q / SY BG 1023-2022.

[0090] The relevant data and test results of Example 2 are shown in Table 1.

[0091] Example 3

[0092] The material of continuous tube 1 is CT80 grade carbon steel, and the material of tool cylinder 2 is dissimilar metal 20CrMo. The procedure is as follows:

[0093] Step 1: Anneal the 20CrMo tool holder;

[0094] Annealing is performed on the 20CrMo tool cylinder before welding to improve various structural defects and residual stress caused during the welding process.

[0095] Step 2: Straighten the pipe ends, cut the pipe, and fix it.

[0096] First, use straightening equipment to complete the straightening operation within 3 meters of the predetermined position of the continuous tube 1 (oil pipe). After straightening, the straightness B of the continuous tube 1 within 1.5m is required to be less than 2mm.

[0097] Next, cut the continuous tube 1 and place the cut continuous tube 1 and tool cylinder 2 on the welding assembly stand and fix them securely.

[0098] Step 3: Surface cleaning and beveling;

[0099] First, use an internal grinder and an angle grinder to clean the oil stains within 15mm of the inner surface and 25mm of the outer surface of the joint of the continuous tube 1 and the tool cylinder 2 until the tube ends of the continuous tube 1 and the tool cylinder 2 are exposed with a metallic luster; the internal grinder uses a 90-mesh internal grinder head and the angle grinder uses a 140-mesh angle grinder disc.

[0100] Then, a mechanical beveling machine is used to bevele the joint ends of the continuous pipe 1 and the tool cylinder 2 respectively, and the beveling angle of the processed pipe is 37°.

[0101] Step 4: Perform pipe end assembly;

[0102] Clamp the continuous pipe 1 end and the tool cylinder 2 end to be welded on the welding assembly stand, adjust the position of the two opposite ends to make the pipe ends aligned and the assembly gap 2.4mm, and use a ruler and level to measure in the vertical and horizontal directions of the pipe ends to ensure that there is no misalignment between the continuous pipe 1 and the tool cylinder 2 assembly.

[0103] Step 5: Clamp the cooling block and insulation cotton;

[0104] At one end of the continuous pipe 1 that needs to be welded, a water-cooled copper block is clamped 12mm away from the welding bevel; at one end of the tool cylinder 2 that needs to be welded, a heat-insulating cotton is clamped 12mm away from the welding bevel.

[0105] Step 6, welding;

[0106] First, manual tungsten inert gas welding is used, and the welding position is 5G all-position welding. Three-point positioning welding is performed at the 12 o'clock, 3 o'clock and 9 o'clock positions of the weld.

[0107] Then, a two-layer multi-segment welding method is adopted, with a root pass welding current of 65A and a cover pass welding current of 80A. After welding, the tool cylinder 2 is kept warm for 5 minutes.

[0108] Then use a wire brush to clean the spaces between the layers until the metallic luster is exposed;

[0109] Step 7, weld treatment;

[0110] After completing the cover welding, remove the water-cooled copper block, first use a 90-grit elastic grinding disc for rough grinding, then use a 130-grit elastic grinding disc for fine grinding, and grind the weld seam until it is flush with the base material. The grinding direction is parallel to the pipe axis.

[0111] Radiographic testing shall be performed on the weld seams of the finished product, in accordance with the standard Q / SY BG 1023-2022.

[0112] The relevant data and test results of Example 3 are shown in Table 1.

[0113] Example 4

[0114] The material of continuous tube 1 is CT80 grade carbon steel, and the material of tool cylinder 2 is dissimilar metal 20CrMo. The procedure is as follows:

[0115] Step 1: Anneal the 20CrMo tool holder;

[0116] Annealing is performed on the 20CrMo tool cylinder before welding to improve various structural defects and residual stress caused during the welding process.

[0117] Step 2: Straighten the pipe ends, cut the pipe, and fix it.

[0118] First, use straightening equipment to complete the straightening operation within 3 meters of the predetermined position of the continuous tube 1 (oil pipe). After straightening, the straightness B of the continuous tube 1 within 1.5m is required to be less than 2mm.

[0119] Next, cut the continuous tube 1 and place the cut continuous tube 1 and tool cylinder 2 on the welding assembly stand and fix them securely.

[0120] Step 3: Surface cleaning and beveling;

[0121] First, use an internal grinder and an angle grinder to clean the oil stains within 15mm of the inner surface and 25mm of the outer surface of the joint between the continuous tube 1 and the tool cylinder 2 until the ends of the continuous tube 1 and the tool cylinder 2 are exposed with a metallic luster; the internal grinder uses an 80-mesh internal grinder head and the angle grinder uses a 150-mesh angle grinder disc.

[0122] Then, a mechanical beveling machine is used to bevele the joint ends of the continuous pipe 1 and the tool cylinder 2 respectively, and the beveling angle of the processed pipe is 37°.

[0123] Step 4: Perform pipe end assembly;

[0124] Clamp the continuous pipe 1 end and the tool cylinder 2 end to be welded on the welding assembly stand, adjust the positions of the two opposite ends to make the pipe ends aligned and the assembly gap 2.3mm; and use a ruler and level to measure in the vertical and horizontal directions of the pipe ends to ensure that there are no misalignments in the assembly of continuous pipe 1 and tool cylinder 2.

[0125] Step 5: Clamp the cooling block and insulation cotton.

[0126] At one end of the continuous pipe 1 that needs to be welded, a water-cooled copper block is clamped 15mm away from the welding bevel; at one end of the tool cylinder 2 that needs to be welded, a heat-insulating cotton is clamped 10mm away from the welding bevel.

[0127] Step 6: Perform welding;

[0128] First, manual tungsten inert gas welding is used, and the welding position is 5G all-position welding. Three-point positioning welding is performed at the 12 o'clock, 3 o'clock and 9 o'clock positions of the weld.

[0129] Then, a two-layer multi-segment welding method is adopted, with a root pass welding current of 65A and a cover pass welding current of 80A. After welding, the tool cylinder 2 is kept warm for 5 minutes.

[0130] Then use a wire brush to clean the spaces between the layers until the metallic luster is exposed;

[0131] Step 7, weld treatment;

[0132] After completing the cover welding, remove the water-cooled copper block, first use a 100-grit elastic grinding disc for rough grinding, then use a 120-grit elastic grinding disc for fine grinding, and grind the weld seam until it is flush with the base material. The grinding direction is parallel to the pipe axis.

[0133] Radiographic testing shall be performed on the weld seams of the finished product, in accordance with the standard Q / SY BG 1023-2022.

[0134] The relevant data and test results of Example 4 are shown in Table 1.

[0135] Table 1. Comparison of relevant data for the four embodiments

[0136]

[0137] See the X-ray inspection photograph of Example 1. Figure 3 and Figure 4 See the X-ray inspection photograph for Example 2. Figure 5 and Figure 6 See the X-ray inspection photograph in Example 3. Figure 7 and Figure 8 See the X-ray inspection photograph in Example 4. Figure 9 and Figure 10 .

[0138] As illustrated in Table 1, the welding method of this invention was used to successfully weld the 20CrMo tool cylinder of carbon steel continuous tubing and complete the well run, in response to the customer's requirements. This method of connecting the 20CrMo tool cylinder to the continuous tubing using welding is the first of its kind in China.

Claims

1. A welding method for butt welding of a carbon steel continuous pipe to a dissimilar metal 20CrMo tool cylinder, characterized in that, Follow these steps: Step 1, anneal the tool holder. The specific process is as follows: Before welding, the tool tube made of 20CrMo material is annealed to reduce the material strength of the tool tube so that it matches the strength of the continuous tube made of CT80 material. Step 2 involves straightening, cutting, and fixing the continuous tube. The specific process is as follows: Using straightening equipment, straightening operations are completed within a 3-meter range of the predetermined pipe end of the continuous tube. After straightening, the straightness B of the continuous tube within 1.5m is required to be less than 2mm. Then, pipe cutting equipment is used to cut the continuous tube. Step 3, cleaning and beveling the inner and outer surfaces of the rim, the specific process is as follows: First, using an internal grinder and an angle grinder, the inner surface of the continuous tube and the tool barrel joint is cleaned of oil stains within 15mm and the outer surface of the joint until the ends of the continuous tube and the tool barrel are exposed with a metallic luster. The internal grinder uses an 80-100 grit internal grinder head, and the angle grinder uses a 120-150 grit angle grinder disc. Then, a mechanical beveling machine is used to bevele the joint ends of the continuous tube and the tool barrel. Step 4 involves assembling and positioning the pipe ends for welding. The specific process is as follows: Clamp the continuous pipe end and tool cylinder end to be welded on the welding assembly stand, adjust the position of the two opposite ends to make the pipe end assembly straight with an assembly gap of 2.2-2.5mm, and use a ruler and level to measure in the vertical and horizontal directions of the pipe end to ensure that the continuous pipe and tool cylinder assembly is without misalignment, and position and weld at the 3, 9 and 12 o'clock positions of the weld respectively; Step 5, clamp the cooling block and insulation cotton. The specific process is as follows: Clamp a water-cooled copper block at one end of the continuous pipe to be welded, 10-15mm away from the welding bevel; clamp thermal insulation cotton at one end of the tool cylinder to be welded, 10-15mm away from the welding bevel. Step 6, welding, the specific process is as follows: First, manual tungsten inert gas welding is used, and the welding position is 5G all-position welding. Three-point positioning welding is performed at the 12 o'clock, 3 o'clock and 9 o'clock positions of the weld. Then, a two-layer, multi-segment welding method is used to complete the root pass welding and the cover pass welding, and to insulate the tool cylinder. Then, use a wire brush to clean the spaces between the layers until the metallic luster is exposed; Step 7, weld treatment, the specific process is as follows: After completing the cover welding, remove the water-cooled copper block, first use an 80-100 grit elastic grinding disc for rough grinding, then use a 120-150 grit elastic grinding disc for fine grinding, and grind the weld seam until it is flush with the base material, with the grinding direction parallel to the pipe axis.

2. The welding method for butt welding of carbon steel continuous pipe to dissimilar metal 20CrMo tool cylinder according to claim 1, characterized in that, In step 3, the bevel angle after processing is 37°.

3. The welding method for butt welding of carbon steel continuous pipe to dissimilar metal 20CrMo tool cylinder according to claim 1, characterized in that, In step 6, the current for the root pass is 65A, the current for the cover pass is 80A, and the holding time is 5 minutes.

Images