Novel low-magnetic steel flat position trolley automatic welding method

Abstract

The invention discloses a novel low-magnetic steel flat position trolley automatic welding method, a welding trolley is adopted to carry a welding gun, a matched welding wire is used, binary mixed gas is used as protective gas, flat position welding of low-magnetic steel is carried out according to corresponding welding parameters, and the automatic welding method comprises welding conditions and welding procedures. The welding trolley is adopted for automatic, continuous and stable welding, so that the risk of welding deformation can be reduced, excessive weld joints cannot be generated, the situation that the welding efficiency is affected by repeated grinding and slag removal is avoided, the waiting time is shortened, the labor intensity is relieved, and the working environment is improved; therefore, by the adoption of the welding method, the welding continuity is good, and weld joints and products which are attractive in shape and high in quality can be obtained.

Description

Technical Field

[0001] This invention relates to the field of automatic metal welding technology, and in particular to a novel automatic welding method for a low-magnetic steel flat-position trolley. Background Technology

[0002] Low-magnetic steel, as a material with low magnetic permeability and low remanence, is widely used in some fields with strict requirements for magnetic field environment, such as power transformers, nuclear magnetic resonance devices, and shipbuilding, to avoid the magnetic field from having a significant impact on the performance of the equipment.

[0003] Low-magnetic steel has poor thermal conductivity and a large coefficient of linear expansion. These characteristics work together to easily lead to heat accumulation and uneven stress distribution in the welding area, thereby inducing a variety of defects, including hot crystallization cracks, hydrogen porosity, significant welding deformation (such as angular deformation and warping), and excessive welding residual stress, which seriously affect the quality of the joint and the stability of the structure.

[0004] Traditional manual welding is limited by human strength, cannot be done continuously, has many weld joints, and requires multiple grinding and slag removal processes, which seriously affects welding efficiency and welding quality. At the same time, manual welding is slow and the heat input is high, which can easily lead to welding deformation and affect the quality of product construction. Summary of the Invention

[0005] In view of the above-mentioned prior art, the present invention provides a novel automatic welding method for a flat-position trolley of low-magnetic steel, which solves the problems of low efficiency and difficulty in guaranteeing welding quality in manual welding of low-magnetic steel.

[0006] To achieve the above objectives, the technical solution of this invention is implemented as follows: A novel automatic welding method for low-magnetic steel in a flat position using a welding carriage involves using a welding carriage equipped with a welding torch, a matching welding wire, and a binary mixed gas as the shielding gas. The method performs flat position welding of low-magnetic steel according to the corresponding welding parameters. The automatic welding method includes welding conditions and welding procedures.

[0007] Furthermore, welding conditions include the base material, welding equipment, welding materials, and welding parameters.

[0008] Furthermore, the base material for welding is 03Cr21Ni14Mo3N low-magnetic steel with a tensile strength Rm≥600N / mm². 2 Impact absorption energy at -40℃ ≥47J, base material thickness is 3-9mm.

[0009] Furthermore, the welding equipment is a fully automated welding carriage equipped with a MIG welding torch.

[0010] Further, the welding material is MIG welding wire with Φ=1.0, the protective gas is binary mixed gas with 97.5% Ar+2.5% CO2, and the protective gas flow is 15-25 L / min.

[0011] Further, the welding parameters are as follows: The base welding current is 140-170 A, the voltage is 20-26 V, and the welding speed is 20-30 cm / min. The filling and covering welding current is 140-170 A, the voltage is 20-26 V, and the welding speed is 20-30 cm / min.

[0012] Further, the welding procedure is as follows: ① A "V" type groove is adopted, and the assembly gap is 0-2 mm; ② No preheating is performed before welding, and the groove and the two sides of the groove are dried to remove moisture; ③ The interpass temperature is ≤100℃, and the linear energy is ≤15 kJ / cm during the welding process; ④ After the welding is completed, the weld is polished, and the welding slag is cleaned; ⑤ The back carbon arc is gas planed to clean the root, and polished; ⑥ The welded seam after welding is completed is subjected to appearance inspection; ⑦ The welded seam is subjected to non-destructive testing.

[0013] Further, the welding procedure is as follows: ① A "V" type groove is adopted, and the single side slope is 30°-32.5°, no blunt edge is left, and the assembly gap is 0-2 mm; ② No preheating is performed before welding, and the groove and the two sides of the groove within the range of 30 mm-70 mm are dried to remove moisture; ③ The interpass temperature is ≤100℃, and the linear energy is ≤15 kJ / cm during the welding process; ④ After each welding is completed, the weld is polished according to the slag removal condition, and the welding slag is cleaned; ⑤ The back carbon arc is gas planed to clean the root, and then polished to expose the metal luster; ⑥ The welded seam after welding is completed is subjected to appearance inspection, and after the appearance inspection is qualified, it is placed for 48 h; ⑦ The welded seam is subjected to non-destructive testing, the radiographic non-destructive testing result meets the requirement of grade II film, and the mechanical property test meets the qualified index of low magnetic steel.

[0014] Further, the track of the full-automatic welding trolley is fixed on the base steel plate by a vacuum suction cup.

[0015] The beneficial effects of the present application are as follows: 1、The welding trolley can automatically, continuously and stably perform welding, so that the risk of welding deformation is reduced, excessive weld joints are not generated, repeated polishing and slag removal do not affect the welding efficiency, and thus the waiting time is reduced, the labor intensity is reduced, and the working environment is improved, so that the welding continuity of the welding method in the application is good, and a weld and a product with good appearance and high quality can be obtained. 2、The welding method can significantly reduce the risks of hot cracking, hydrogen pores and welding deformation by drying and removing moisture before welding, so that the stability of the welding process can be improved, the weld quality can be ensured, and pores can be reduced.

[0016] 3、The radiographic results of the weld of the welding method meet the corresponding standard requirements, and the mechanical properties of the weld joint destruction test meet the technical requirements of 03Cr21Ni14Mo3N plate and matching welding material, so that a feasible welding method is provided for flat position welding of new low magnetic steel. BRIEF DESCRIPTION OF DRAWINGS

[0017] Fig. 1 The drawing shows the bevel and assembly state of the flat position trolley automatic welding method of the new low magnetic steel. Fig. 2 The drawing shows the weld arrangement state of the flat position trolley automatic welding method of the new low magnetic steel.

[0018] In the drawing, a is the base material thickness, b is the assembly gap, c is the single side slope, d is the weld front width, e is the weld front excess height, f is the weld back excess height, and g is the weld back width. DETAILED DESCRIPTION

[0019] The technical solution of the application will be further described in detail below in combination with the drawings and specific embodiments. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as understood by those skilled in the art to which the application belongs. The terms used in the specification of the application herein are only for the purpose of describing specific embodiments and are not intended to limit the application.

[0020] EMBODIMENT Referring to the drawings, Figs. 1-2 The application provides a flat position trolley automatic welding method for new low magnetic steel, which uses a welding trolley to carry a welding gun, uses matching welding wire, uses binary mixed gas as protective gas, and performs flat position welding of low magnetic steel according to corresponding welding parameters. The specific welding method is as follows: 1、Welding conditions ①Welding base material: low magnetic steel 03Cr21Ni14Mo3N, tensile strength Rm≥600N / mm 2 , impact energy at -40℃≥47J, base material thickness a is 6mm; ②Welding equipment: full-automatic welding trolley with MIG welding gun; ③Welding material: MIG welding wire with Φ = 1.0 is selected, and the protective gas is a binary mixed gas of 97.5% Ar + 2.5% CO2, and the protective gas flow is 15-25 L / min; ④Welding parameters: base welding current 140-160 A, voltage 21-24 V, and welding speed 20-22 cm / min; filling and covering welding current 150-170 A, voltage 21-24 V, and welding speed 20-22 cm / min; 2)、Welding procedure ①V-shaped groove is adopted, and the single-side slope c is 30°-32.5°, without blunt edge, and the assembly gap b is 0-2 mm; ②No preheating before welding, and the groove and the range of 50 mm on both sides of the groove are dried and dehumidified; ③The interpass temperature during welding is ≤100℃, and the linear energy is <15 kJ / cm; ④After each pass of welding is completed, the weld is polished according to the deslagging condition, and the welding slag is cleaned; ⑤The back is cleaned by carbon arc air gouging, and then polished to expose the metal luster; ⑥The welded joint after welding is subjected to appearance inspection, and after the appearance inspection is qualified, it is placed for 48 h; ⑦Welding non-destructive testing is carried out, the radiographic non-destructive testing result meets the requirements of Class I film, the mechanical property test meets the qualified index of low magnetic steel, and the relative magnetic permeability of the welded joint metal meets the standard requirements.

[0021] Welding seam detection 1、Appearance inspection (evaluation standard: CB / T 3802-1997)

[0022] 2、Non-destructive testing (evaluation standard: CB / T 3558-2011) After X-ray film examination, no pores, cracks, incomplete fusion, incomplete penetration and other defects are found in the welding seam, and the welding quality is evaluated as Class I.

[0023] 3、Mechanical property test 1)Welded joint tensile test (test standard: GB / T 2651-2023) Test sample 1

[0024] Test sample 2

[0025] Conclusion: According to the test data, the tensile strength of the two samples is 713N / mm 2 , 701N / mm 2 , respectively, which exceeds the above value, and the sample is broken. The tensile strength of the base material is greater than or equal to 600N / mm 2 .

[0026] 2) Impact test (test standard: GB / T2650-2022)

[0027] Conclusion: According to the test data, the impact test results of the three groups meet the requirement that the impact energy of the base material at-40℃ should be greater than or equal to 47J.

[0028] 4, Relative permeability detection of weld metal The maximum relative permeability of each point in the weld metal area is 1.008 by Foerster contact permeameter detection, which meets the standard requirement of the relative permeability of the weld metal (μ r ≤ 1.01).

[0029] Preferably, the track of the full-automatic welding trolley is fixed on the steel plate by vacuum chuck. Since the magnetic property of the low-magnetic steel plate is weak, the magnetic track cannot be firmly adsorbed on the material surface, so the track is fixed by vacuum chuck to ensure that the welding trolley welds along the specified path.

[0030] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any skilled person in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. The protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A novel low magnetic steel flat car automatic welding method, characterized in that: The automatic welding method comprises welding conditions and a welding procedure.

2. A novel low magnetic steel horizontal position trolley automatic welding method according to claim 1, characterized in that, The welding conditions comprise a welding base material, welding equipment, welding material and welding parameters.

3. A novel low magnetic steel horizontal position trolley automatic welding method according to claim 2, characterized in that, The welding base material is 03Cr21Ni14Mo3N low magnetic steel, the tensile strength Rm≥600 N / mm 2 , the impact absorption energy at -40℃ is ≥47 J, and the base material thickness (a) is 3-9 mm.

4. The novel low magnetic steel horizontal position trolley automatic welding method according to claim 2, characterized in that, The welding equipment is a full-automatic welding trolley carrying a MIG welding gun.

5. The novel low magnetic steel horizontal position trolley automatic welding method according to claim 2, characterized in that, The welding material is a MIG welding wire with a diameter of 1.0, and the protective gas is a binary mixed gas of 97.5% Ar and 2.5% CO2, with a protective gas flow of 15-25 L / min.

6. A novel low magnetic steel horizontal position trolley automatic welding method according to claim 2, characterized in that, The welding parameters are as follows: The welding current for the backing welding is 140-170 A, the voltage is 20-26 V, and the welding speed is 20-30 cm / min; The welding current for the filling and surface welding is 140-170 A, the voltage is 20-26 V, and the welding speed is 20-30 cm / min.

7. The novel low magnetic steel horizontal position trolley automatic welding method according to claim 1, characterized in that, The welding procedure is as follows: ① A "V" type groove is adopted, and the assembly gap (b) is 0-2 mm; ② No preheating is performed before welding, and the groove and the groove sides are dried to remove moisture; ③ The interpass temperature is ≤100℃, and the linear energy is ≤15 kJ / cm during the welding process; ④ After the welding is completed, the weld is polished, and the welding slag is cleaned; ⑤ The back carbon arc is gas planed to clean the root, and then polished; ⑥ The welded seam is subjected to appearance inspection; ⑦ The welded seam is subjected to non-destructive testing.

8. The novel low-magnetic steel horizontal position trolley automatic welding method according to claim 7, characterized in that, The welding procedure is as follows: ① A "V" type groove is adopted, and the single-side slope (c) is 30°-32.5°, and no blunt edge is left, and the assembly gap (b) is 0-2 mm; ② No preheating is performed before welding, and the groove and the groove sides within a range of 30-70 mm are dried to remove moisture; ③ The interpass temperature is ≤100℃, and the linear energy is ≤15 kJ / cm during the welding process; ④ After each welding is completed, the weld is polished according to the slag removal condition, and the welding slag is cleaned; ⑤ The back carbon arc is gas planed to clean the root, and then polished to expose the metal luster; ⑥ The welded seam is subjected to appearance inspection, and after the appearance inspection is qualified, the welded seam is placed for 48 h; ⑦ The welded seam is subjected to non-destructive testing, and the radiographic non-destructive testing result meets the requirements of a Class II film, and the mechanical property test meets the qualified indexes of the low magnetic steel.

9. A novel low magnetic steel horizontal position trolley automatic welding method according to claim 1, characterized in that, The track of the full-automatic welding trolley is fixed on the base material steel plate by a vacuum suction cup.

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