Hot wire TIG and submerged arc hybrid welding method for high-strength steel conical workpiece

Abstract

The invention relates to a hot wire TIG and submerged arc hybrid welding method for a high-strength steel conical workpiece, which adopts a manner of backing welding by hot wire argon tungsten-arc welding with higher welding wire filling efficiency and filling a cover surface by submerged arc welding, and optimizes the aspects of part groove processing, diameter matching and welding posture. The groove is a small-angle butt joint groove with a gap, the weld groove is in a 30-degree V shape, the back face is a truncated edge, and the proper groove angle is guaranteed while size interference is avoided. When parts are assembled, the diameter of a welding connector is matched, products which do not meet requirements are removed, and the diameter matching effect is improved by adjusting gaps. A stable molten pool is formed by adjusting the welding posture of the conical workpiece, and the two sides of a formed welding bead are uniform and symmetrical. And during submerged-arc welding, a molten pool can be effectively protected by keeping the posture, and the defect of incomplete fusion is avoided. The quality of the obtained welding seam meets the use requirement of the conical workpiece, the defects of cracks, air holes or incomplete fusion do not occur, and the welding efficiency is improved.

Description

Technical Field

[0001] The invention relates to the field of high-strength steel welding manufacturing, and is a hot wire TIG+submerged arc composite welding method for a high-strength steel conical workpiece with a wall thickness of more than 10 mm. Background Art

[0002] A conical workpiece is welded by multiple conical parts. The material is high-strength steel. The wall thickness of the butt weld between the conical parts is ≥10mm and the diameter is ≥Φ500mm. Due to the harsh use environment of the workpiece, strict requirements are imposed on the quality of its weld. Cracks, pores or unfused defects are not allowed. The original method of tungsten inert gas arc welding is used to perform multi-layer multi-pass welding of more than 10 layers until the weld is full. The overall welding time is long, the equipment load is large, and the process control cost is high. In order to improve the welding efficiency while ensuring the welding quality, a new method needs to be developed to achieve efficient and stable welding of the conical workpiece weld. Hot wire TIG welding and submerged arc welding are suitable for welding thick walls with large wire filling, and the welding quality is good. The composite welding method of hot wire TIG welding for base welding and submerged arc welding for filling and covering is suitable for the welding of the above-mentioned thick-walled large-diameter conical workpiece. Since the two methods are suitable for different weld grooves and thicknesses, how to design the welding groove and welding process of the parts has become a key issue of the composite welding method.

[0003] The present invention combines the adaptability range of hot wire TIG welding and submerged arc welding to the weld shape, designs a special welding groove, and controls the weld misalignment and molten pool position during assembly and welding, thereby ensuring the welding quality of high-strength steel tapered workpieces and improving welding efficiency.

[0004] In the invention patent with the publication number CN114043108A, a plasma + TIG welding method for ultra-high-strength steel cylindrical parts is disclosed, which utilizes the characteristics of high plasma energy density and deep welding penetration to improve welding efficiency, and makes requirements for the part accuracy and positioning welding point control required to achieve the welding method. However, this method is not applicable to conical parts that cannot meet the requirements of their processing accuracy and assembly clearance, and the welding efficiency of plasma + TIG for conical workpieces with a wall thickness of ≥10mm and a diameter of ≥Φ500mm is not as good as that of hot wire TIG + submerged arc welding.

[0005] In the invention patent with publication number CN118848173A, a method for vertical welding of high-strength steel penetration butt welds is introduced. The weld grooves of two high-strength steel workpieces to be welded are aligned and placed vertically, and argon-rich gas shielded welding is performed vertically upward welding and then root cleaning welding to ensure the welding quality of workpieces with a thickness of less than 40mm. This method is suitable for butt longitudinal welds and there is space for root cleaning operation on the back of the weld, but it is not suitable for the circumferential weld of conical workpieces. Summary of the invention

[0006] In order to overcome the problems of low welding efficiency and difficulty in stabilizing welding for a long time in existing welding methods, the present invention proposes a hot wire TIG+submerged arc composite welding method for high-strength steel conical workpieces.

[0007] The conical workpiece of the present invention is welded in sequence by a head ring, a cone section and a tail ring. The specific process of hot wire TIG + submerged arc hybrid welding is:

[0008] Step 1, processing and cleaning of welding groove:

[0009] The processing of the welding groove is to process the welding groove at the welding position of the head ring and the cone section, and the welding position of the cone section and the tail ring;

[0010] The welding groove structures of the welding position between the head ring and the cone section and the welding position between the cone section and the tail ring are the same and mirror-symmetrical.

[0011] Step 2, assembly of conical workpieces:

[0012] The pair assembly of the conical workpieces is to assemble and position the head ring, the cone section and the tail ring in sequence to complete the pair assembly of the conical workpieces.

[0013] The misalignment of the tail ring, cone section and head ring is less than 1 mm.

[0014] When assembling the conical workpieces, place the tail ring on a stable platform to ensure that it does not shake or slip. Place the cone segment on the upper end surface of the tail ring, and leave a gap of L2 between the contact surface of the tail ring and the cone segment; perform argon arc welding for positioning and sealing, and obtain a welded conical workpiece consisting of the tail ring and the cone segment.

[0015] Place the head ring 1 on the upper end surface of the cone section of the assembly weldment, make the lower end surface of the head ring contact with the upper end surface of the cone section, and leave a gap of L1 between the contact surfaces of the head ring and the cone section; perform argon arc welding for positioning and sealing, and obtain the assembly weldment of the conical workpiece.

[0016] When assembling the head ring and the cone section, compare the diameters of the end faces on both sides of the weld, select the parts that satisfy Formula 1 for pairing, and then adjust the gap L1 during assembly according to Formula 2 to achieve accurate matching of the diameters:

[0017] |Φ2-Φ1|≤0.5 (1)

[0018] L1=L0+(Φ2 / Φ1-1)T1 (2)

[0019] Among them: Φ1 is the diameter of the welding end face of the head ring 1 obtained by actual measurement, unit: mm; Φ2 is the diameter of the end face of the welding side of the cone section 2 and the head ring 1 obtained by actual measurement, unit: mm; L1 is the gap that should be controlled when assembling the butt weld when assembling the head ring 1 and the cone section 2, unit: mm; L0 is the theoretical gap for assembling the above butt weld, unit: mm; T1 is the theoretical distance from the top of the cone to the welding end face of the head ring 1 and the cone section 2, unit: mm.

[0020] When assembling the cone section 2 and the tail ring 3, formula 3 should be satisfied, and the assembly clearance should be controlled according to formula 4:

[0021] |Φ4-Φ3|≤0.5 (3)

[0022] L2=L0+(Φ4 / Φ3-1)T2 (4)

[0023] Among them: Φ3 is the diameter of the end face of the welding side of the cone section 2 and the tail ring 3 obtained by measurement, unit mm; Φ4 is the diameter of the welding end face of the tail ring 3 obtained by measurement, unit mm; L2 is the gap that should be controlled when assembling the butt weld when assembling the cone section 2 and the tail ring 3, unit mm; L0 is the theoretical gap for assembling the above butt weld, unit mm; T2 is the theoretical distance from the top of the cone to the welding end face of the cone section 2 and the tail ring 3, unit mm.

[0024] Step 3: Clamp the welded parts and adjust the posture:

[0025] The conical workpiece assembly is transferred to the platform of the rotary positioner, and the misalignment between the axis of the assembly and the axis of the rotary positioner is less than 2 mm. The posture of the assembly is adjusted so that its posture and the welding gun 4 meet the workpiece welding posture requirements of hot wire TIG + submerged arc welding.

[0026] When adjusting the posture of the welded parts, the conical workpiece is rotated along its own axis, and the generatrix where the welding point is located is always parallel to the ground during the rotation; the position of the welding gun is adjusted so that the tungsten electrode tip of the welding gun is aligned with the center of the weld width for welding.

[0027] Step 4, hot wire TIG welding:

[0028] The assembly weld has two welds, namely a first weld 5 between the head ring and the cone section and a second weld 6 between the cone section and the tail ring. The two welds are welded successively by hot wire TIG welding to complete the hot wire tungsten inert gas arc welding of the two welds.

[0029] The specific process of hot wire tungsten inert gas arc welding is:

[0030] Ⅰ Use hot wire TIG welding to weld the second weld between the cone section and the tail ring, and perform a full circle of continuous welding. When the welding gun passes the welding starting point again, keep the welding parameters unchanged and continue welding for 10mm. After that, start the decay mode, so that the welding current decays linearly within 3s until the arc is extinguished, and the argon shielding gas is terminated 6s after the arc is extinguished. The hot wire TIG welding of the second weld is completed.

[0031] II Repeat the process of welding the second weld to complete the hot wire TIG welding of the first weld.

[0032] The welding current of hot wire TIG welding is 220A, the welding voltage is 10V, the hot wire voltage is 5.0V, the wire feeding speed is 120m / h, and the welding speed is 7m / h.

[0033] Step 5, submerged arc welding:

[0034] Before submerged arc welding, the surfaces of the welds completed by hot wire TIG welding are polished and cleaned.

[0035] After cleaning, the second weld between the cone section and the tail ring is welded by submerged arc welding; after the second weld is welded, the first weld between the head ring and the cone section is welded. At this point, the welding of the cone workpiece is completed.

[0036] The submerged arc welding has a welding current of 310A, a welding voltage of 30V, and a welding speed of 20m / h.

[0037] The present invention adopts a method of hot wire tungsten inert gas arc welding for bottom welding and submerged arc welding for filling and covering with higher welding wire filling efficiency to replace tungsten inert gas arc welding for welding the conical workpiece.

[0038] In order to realize the above welding method, the present invention puts forward the following requirements in terms of part groove processing, diameter matching, and welding posture:

[0039] 1. Design and process the welding butt groove of the conical workpiece according to the characteristics of the depth and width of the composite welding method. Since the thick wall small angle groove interferes with the welding gun nozzle, and the large angle groove increases the cross-sectional area of ​​the weld, the welding time is prolonged. Combined with the production experience of a large number of similar products, the design Figure 4 The small angle butt groove with gap shown in the figure has a single-sided 30° V-shaped groove on the front of the weld and a 2mm deep blunt edge on the back to avoid dimensional interference while ensuring an appropriate groove angle. The above welding groove is processed in the parts state before welding the head ring 1, cone section 2, and tail ring 3 for assembly welding.

[0040] 2. Compare and match the diameters of weld joints when assembling parts. Misalignment during weld butt jointing will increase the difficulty of welding quality control and deteriorate the product forming accuracy. Therefore, when designing the groove, the theoretical diameters of the joints of the parts on both sides of the weld are equal. However, due to the errors of the parts themselves and the machining errors of the grooves, there are differences in the diameters of the joints of the parts on both sides of the weld. Therefore, when assembling, the diameters must be compared first, and products that do not meet the requirements must be eliminated. Secondly, the gap must be adjusted to further improve the diameter matching effect to achieve the following results: Figure 5 The assembly effect is shown.

[0041] 3. Use a rotary positioner to adjust the welding posture of the conical workpiece. When welding the circumferential weld on the assembled conical workpiece, in order to ensure a uniform and stable molten pool during hot wire TIG welding, the conical workpiece is rotated along its own axis, and the generatrix where the welding point is located is always parallel to the ground during the rotation process; adjust the position of the welding gun so that the tungsten tip of the welding gun is aligned with the center of the weld width for welding. Figure 6 As shown in Figure b, a stable molten pool is formed, and both sides of the weld are evenly symmetrical. During submerged arc welding, maintaining the above posture can maximize the protective effect of the flux on the molten pool and avoid defects such as lack of fusion caused by the welding gun deviating from the center of the weld.

[0042] The present invention adopts a hot wire TIG welding and submerged arc welding hybrid welding method with a welding efficiency more than three times higher than TIG welding to weld high-strength steel conical workpieces with a wall thickness of ≥10mm, and has targeted requirements in terms of welding groove design, assembly diameter control, and welding posture. The product welding is carried out according to the above-mentioned hybrid welding method and control requirements. The verification results show that the use of this method can improve the welding efficiency while the quality of the obtained weld meets the use requirements of the conical workpiece, and no cracks, pores or unfused defects occur. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic diagram of the structure of the head ring.

[0044] Figure 2 It is a structural diagram of the cone section.

[0045] Figure 3 It is a schematic diagram of the structure of the tail ring.

[0046] Figure 4 It is a cross-sectional diagram of the welding groove.

[0047] Figure 5 It is the front view of the tapered workpiece assembly structure.

[0048] Figure 6 is a schematic diagram of the welding posture of a conical workpiece; Figure 6 a is the main view, Figure 6 b is Figure 6A partial enlarged view of area A in a.

[0049] Figure 7 It is a flow chart of the present invention.

[0050] In the figure: 1. head ring; 2. cone section; 3. tail ring; 4. welding gun; 5. first weld; 6. second weld. DETAILED DESCRIPTION

[0051] This embodiment is a method for welding a conical workpiece. The conical workpiece is welded in sequence by a head ring 1, a cone section 2 and a tail ring 3. The specific process is:

[0052] Step 1, processing and cleaning of welding groove:

[0053] Processing at the welding ends of the head ring and the cone section, and the cone section and the tail ring Figure 4 The welding grooves shown in the figure are the same in structure and mirror-symmetrical. Before assembly, the welding grooves of each part must be cleaned until there is no visible oil, iron filings or oxide scale to ensure the assembly and welding effect.

[0054] Step 2, assembly of conical workpieces:

[0055] Place the tail ring 3 on a stable platform to ensure that it does not shake or slip. Place the cone section 2 on the upper end surface of the tail ring 3, and leave a gap of L2 between the contact surface of the tail ring and the cone section; perform argon arc welding for positioning and sealing, and obtain a welded assembly consisting of the tail ring 3 and the cone section 2.

[0056] Place the head ring 1 on the upper end surface of the cone section of the welded component, make the lower end surface of the head ring contact with the upper end surface of the cone section, and leave a gap of L1 between the contact surfaces of the head ring and the cone section; perform argon arc welding for positioning and sealing, obtain the welded component of the conical workpiece, and complete the assembly of the conical workpiece.

[0057] When assembling the head ring 1 and the cone section 2, compare the diameters of the end faces on both sides of the weld, select the parts that satisfy Formula 1 for pairing, and then adjust the gap L1 during assembly according to Formula 2 to achieve accurate matching of the diameters:

[0058] |Φ2-Φ1|≤0.5 (1)

[0059] L1=L0+(Φ2 / Φ1-1)T1 (2)

[0060] Among them: Φ1 is the diameter of the welding end face of the head ring 1 obtained by actual measurement, unit: mm; Φ2 is the diameter of the end face of the welding side of the cone section 2 and the head ring 1 obtained by actual measurement, unit: mm; L1 is the gap that should be controlled when assembling the butt weld when assembling the head ring 1 and the cone section 2, unit: mm; L0 is the theoretical gap for assembling the above butt weld, unit: mm; T1 is the theoretical distance from the top of the cone to the welding end face of the head ring 1 and the cone section 2, unit: mm.

[0061] When assembling the cone section 2 and the tail ring 3, formula 3 should be satisfied, and the assembly clearance should be controlled according to formula 4:

[0062] |Φ4-Φ3|≤0.5 (3)

[0063] L2=L0+(Φ4 / Φ3-1)T2 (4)

[0064] in:

[0065] Φ3 is the diameter of the end face of the welding side of the cone section 2 and the tail ring 3 obtained by measurement, unit mm; Φ4 is the diameter of the welding end face of the tail ring 3 obtained by measurement, unit mm; L2 is the gap that should be controlled when assembling the butt weld when assembling the cone section 2 and the tail ring 3, unit mm; L0 is the theoretical gap for assembling the above butt weld, unit mm; T2 is the theoretical distance from the top of the cone to the welding end face of the cone section 2 and the tail ring 3, unit mm.

[0066] The misalignment of the tail ring, cone section and head ring is less than 1 mm.

[0067] Step 3: Clamp the welded parts and adjust the posture:

[0068] Transfer the conical workpiece assembly to the platform of the rotary positioner, and make the misalignment between the axis of the assembly assembly and the axis of the rotary positioner less than 2 mm. Adjust the posture of the assembly assembly so that its posture and the welding gun 4 meet the above-mentioned workpiece welding posture requirements of hot wire TIG + submerged arc welding, such as Figure 6 a. Figure 6 As shown in b.

[0069] Step 4, hot wire tungsten inert gas welding:

[0070] The welded part has two welds, namely, a first weld 5 between the head ring and the cone section and a second weld 6 between the cone section and the tail ring. The two welds are welded successively by hot wire tungsten inert gas arc welding. Specifically:

[0071] Ⅰ Use hot wire TIG welding to weld the second weld between the cone section and the tail ring, and perform a full circle of continuous welding. When the welding gun passes the welding starting point again, keep the welding parameters unchanged and continue welding for 10mm. Then start the decay mode, so that the welding current decays linearly within 3s until the arc is extinguished, and the argon shielding gas is terminated 6s after the arc is extinguished.

[0072] Ⅱ uses the same method as Ⅰ to weld the first weld between the cone section and the tail ring.

[0073] At this point, the hot wire tungsten inert gas arc welding of the two welds is completed.

[0074] Step 5, submerged arc welding:

[0075] Before starting submerged arc welding, use an elastic grinding disc to grind the weld surface completed by hot wire TIG welding to remove oxides and other impurities, and grind the remaining weld groove smooth to avoid slag inclusions or unfused defects between the transition layers of the two methods.

[0076] After cleaning, the second weld between the cone section and the tail ring is welded by submerged arc welding, and then the first weld between the head ring and the cone section is welded. At this point, the cone workpiece is welded.

Claims

1. A hot wire TIG + submerged arc hybrid welding method for a high-strength steel conical workpiece, wherein the conical workpiece is welded in sequence by a head ring, a conical section and a tail ring; characterized in that: The specific process is: Step 1, processing and cleaning of welding groove: The processing of the welding groove is to process the welding groove at the welding position of the head ring and the cone section, and the welding position of the cone section and the tail ring; Step 2, assembly of conical workpieces: The pair assembly of the conical workpiece is to assemble and position the head ring, the conical section and the tail ring in sequence to complete the pair assembly of the conical workpiece; The misalignment between the tail ring, cone section and head ring is less than 1mm; Step 3: Clamp the welded parts and adjust the posture: Transfer the welded component of the conical workpiece to the platform of the rotary positioner, and make the misalignment between the axis of the welded component and the axis of the rotary positioner less than 2 mm; adjust the posture of the welded component so that its posture and the welding gun meet the workpiece welding posture requirements of hot wire TIG + submerged arc welding; Step 4, hot wire TIG welding: The welded component has two welds, namely a first weld between the head ring and the cone section and a second weld between the cone section and the tail ring; the two welds are welded successively by hot wire TIG welding to complete the hot wire tungsten inert gas arc welding of the two welds; Step 5, submerged arc welding: Before submerged arc welding, the surfaces of the welds completed by hot wire TIG welding are polished and cleaned; After cleaning, the second weld between the cone section and the tail ring is welded by submerged arc welding. After the second weld is welded, the first weld between the head ring and the cone section is welded. At this point, the welding of the cone workpiece is completed.

2. The hot wire TIG + submerged arc hybrid welding method for high-strength steel tapered workpieces as claimed in claim 1, characterized in that: The welding groove structures of the welding position between the head ring and the cone section and the welding position between the cone section and the tail ring are the same and mirror-symmetrical.

3. The hot wire TIG + submerged arc hybrid welding method for high-strength steel tapered workpiece according to claim 1, characterized in that: When assembling the conical workpieces, the tail ring is placed on a stable platform to ensure that it does not shake or slip; the cone section is placed on the upper end surface of the tail ring, and a gap of L2 is left between the contact surfaces of the tail ring and the cone section; argon arc welding is performed to position and seal the bottom to obtain a welded assembly consisting of the tail ring and the cone section; The head ring is placed on the upper end surface of the cone section of the assembly weldment, so that the lower end surface of the head ring contacts the upper end surface of the cone section, and a gap of L1 is left between the contact surfaces of the head ring and the cone section; argon arc welding is performed for positioning and sealing to obtain the assembly weldment of the conical workpiece.

4. The hot wire TIG + submerged arc hybrid welding method for high-strength steel tapered workpiece according to claim 1, characterized in that: When assembling the head ring 1 and the cone section, compare the diameters of the end faces on both sides of the weld, select the parts that satisfy Formula 1 for pairing, and then adjust the gap L1 during assembly according to Formula 2 to achieve accurate matching of the diameters: |Φ2-Φ1|≤0.5 (1) L1=L0+(Φ2 / Φ1-1)T1 (2) Among them: Φ1 is the diameter of the welding end face of the head ring 1 obtained by actual measurement, unit: mm; Φ2 is the diameter of the end face of the welding side of the cone section and the head ring 1 obtained by actual measurement, unit: mm; L1 is the gap that should be controlled when assembling the butt weld when assembling the head ring and the cone section, unit: mm; L0 is the theoretical gap for assembling the above butt weld, unit: mm; T1 is the theoretical distance from the top of the cone to the welding end face of the head ring and the cone section, unit: mm.

5. The hot wire TIG + submerged arc hybrid welding method for high-strength steel tapered workpiece according to claim 1, characterized in that: When assembling the cone section and the tail ring, formula 3 should be satisfied, and the assembly clearance should be controlled according to formula 4: |Φ4-Φ3|≤0.5 (3) L2=L0+(Φ4 / Φ3-1)T2 (4) Among them: Φ3 is the diameter of the end face of the cone section and the tail ring welded on one side, measured in mm; Φ4 is the diameter of the tail ring welded end face, measured in mm; L2 is the gap that should be controlled when assembling the cone section and the tail ring, when assembling the butt weld, in mm; L0 is the theoretical gap for assembling the above butt weld, in mm; T2 is the theoretical distance from the top of the cone to the end face of the cone section and the tail ring weld, in mm.

6. The hot wire TIG + submerged arc hybrid welding method for high-strength steel tapered workpiece according to claim 1, characterized in that: When adjusting the posture of the welded parts, the conical workpiece is rotated along its own axis, and the generatrix where the welding point is located is always parallel to the ground during the rotation; the position of the welding gun is adjusted so that the tungsten electrode tip of the welding gun is aligned with the center of the weld width for welding.

7. The hot wire TIG + submerged arc hybrid welding method for high-strength steel tapered workpiece according to claim 1, characterized in that: The specific process of hot wire tungsten inert gas arc welding is: Ⅰ Use hot wire TIG welding to weld the second weld between the cone section and the tail ring, and perform a full circle of continuous welding; when the welding gun passes the welding starting point again, keep the welding parameters unchanged and continue welding for 10mm, then start the decay mode, so that the welding current decays linearly within 3s until the arc is extinguished, and the argon shielding gas is terminated 6s after the arc is extinguished; Hot wire TIG welding to complete the second weld; II Repeat the process of welding the second weld to complete the hot wire TIG welding of the first weld.

8. The hot wire TIG + submerged arc hybrid welding method for high-strength steel tapered workpiece according to claim 1, characterized in that: The welding current of hot wire TIG welding is 220A, the welding voltage is 10V, the hot wire voltage is 5.0V, the wire feeding speed is 120m / h, and the welding speed is 7m / h.

9. The hot wire TIG + submerged arc hybrid welding method for high-strength steel tapered workpiece according to claim 1, characterized in that: The submerged arc welding has a welding current of 310A, a welding voltage of 30V, and a welding speed of 20m / h.

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