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CN-121972769-A - Gas shielded welding method for low-alloy high-strength steel with tensile strength of 1000MPa

CN121972769ACN 121972769 ACN121972769 ACN 121972769ACN-121972769-A

Abstract

The application relates to the technical field of welding processes, and discloses a gas shielded welding method of low-alloy high-strength steel with 1000 MPa-level tensile strength, which comprises the following steps of S10, groove processing; S20, pre-welding treatment, S30, pad welding copper pads, S40, backing welding, S50, filling welding and S60, cover welding. The application ensures the strength and impact toughness of the welded joint by reasonably arranging the welding heat input and adding other auxiliary measures, and the embodiment has simple operation, easy execution in production and easy popularization to automatic robot welding, thereby realizing high-efficiency production.

Inventors

  • XU BO
  • ZENG WEIMIN
  • DENG BIRONG
  • LIU XUHUI
  • WANG HONGBING
  • LIANG WEN
  • GUO QINGXIAN
  • HUANG XIAOFENG

Assignees

  • 湖南华菱涟钢特种新材料有限公司
  • 湖南华菱涟源钢铁有限公司

Dates

Publication Date
20260505
Application Date
20260210

Claims (10)

  1. 1. A gas shielded welding method for low-alloy high-strength steel with 1000 MPa-level tensile strength is characterized in that the welding mode adopted by the method is gas shielded welding, and welding objects are at least steel plates.
  2. 2. The gas shielded welding method of low alloy high strength steel with tensile strength of 1000MPa level according to claim 1, wherein in S10, the steel plate is V-beveled without blunt edges.
  3. 3. The gas shield welding method for low alloy high strength steel with 1000MPa level tensile strength according to claim 2, wherein the groove angle of the V-groove is 55 °.
  4. 4. The gas shielded welding method of low alloy high strength steel with tensile strength of 1000MPa level according to claim 1, wherein in S20, the pre-welding treatment is pre-welding grinding of the area to be welded and metallic luster is exposed.
  5. 5. The gas shielded welding method for the low-alloy high-strength steel with the tensile strength of 1000MPa grade, which is characterized in that in S30, the pad welding copper pad comprises a pairing gap of the steel plates being 1-1.2 mm and the pad copper pad being arranged on the back of a to-be-welded area.
  6. 6. The gas shielded welding method for low alloy high strength steel with tensile strength of 1000MPa level according to claim 1, wherein S40, S50 and S60 are selected from welding wire and shielding gas, specifically: S40, S50 and S60 are all made of the same welding wire, the diameter of the welding wire is 1.2mm, and the components of the welding wire are as follows ：C 0.08-0.09、Mn 1.62-1.75、Si 0.56-0.59、Cu 0.08-0.18、Cr 0.16-0.22、Mo 0.45-0.55、Ti 0.05-0.1、P≤0.02、S≤0.01; S40, S50 and S60 all adopt the same shielding gas, and the shielding gas comprises 82% of argon and 18% of carbon dioxide.
  7. 7. The gas shielded welding method for the low-alloy high-strength steel with the tensile strength of 1000MPa according to claim 6, wherein the welding parameters of S40 are that the welding voltage is 14-16V, the welding current is 120-140A, the gas flow is 18-20L/min, and the welding speed is 120-150 mm/min.
  8. 8. The gas shielded welding method for the low-alloy high-strength steel with the tensile strength of 1000MPa according to claim 6, wherein the welding parameters of S50 and S60 are that the welding voltage is 22-25V, the welding current is 200-230A, the gas flow is 20-22L/min, and the welding speed is 300-360 mm/min.
  9. 9. The gas shielded welding method for low-alloy high-strength steel with tensile strength of 1000MPa according to claim 8, wherein the interlayer temperature of S50 and S60 is controlled to be 80-100 ℃.
  10. 10. The gas shield welding method of low alloy high strength steel with 1000MPa level tensile strength according to any one of claims 1 to 9, wherein the method is performed by at least an automated welding robot.

Description

Gas shielded welding method for low-alloy high-strength steel with tensile strength of 1000MPa Technical Field The application relates to the technical field of welding processes, in particular to a gas shielded welding method for low-alloy high-strength steel with tensile strength of 1000 MPa. Background The high-strength steel has the advantages of high strength, good plasticity and toughness and the like, and is gradually applied to the fields of engineering machinery, port machinery, coal mine machinery and the like, such as a large-tonnage crane boom, a concrete pump truck boom, a fire truck pump truck boom, a high-performance hydraulic support, an ultra-large-tonnage port crane and the like. Because the light weight requirement is higher and higher, the high-strength steel has great advantages in the aspects of reducing dead weight, improving bearing capacity, reducing transportation and installation cost and the like. The use of high strength grades of low alloy high strength steels has become a selling point and advantage for mechanical products in these industries. The 20MnTiB has higher hardenability, the strength after heat treatment can reach more than 1000MPa, and the cost performance is higher, so that the alloy is widely applied to the production of welding structural members of engineering machinery products, and the manufacturing cost of the engineering machinery is obviously reduced. However, compared with the high-strength steel with a lower strength level, the welding difficulty of 20MnTiB which is subjected to heat treatment to more than 1000MPa is high, and the welding problem is more, because the structure and the performance of a welding heat affected zone are changed under the uneven heating and cooling actions of a welding heat source, and the problems of embrittlement, softening, cracking and the like can occur, so that the welding heat affected zone becomes a weak part of a welding structural member. For welding high-strength steel, although there are many patents of high-strength steel welding methods, such as a 1200MPa high-strength steel non-preheating combined welding method, a 1000 MPa-grade engineering machinery high-strength steel thick plate gas shield welding method, a 900 MPa-grade high-strength steel welding method and the like, the welding process is complex, such as low-strength welding wire backing welding, high-strength steel welding wire filling welding, gouging back chipping, low-strength welding wire back cover and cover surface, post-welding heat preservation and the like, and the welding process is difficult to execute, so that the production efficiency is seriously affected. Disclosure of Invention The application aims to provide a gas shielded welding method for low-alloy high-strength steel with tensile strength of 1000MPa, which aims to solve the technical problems of high welding difficulty and more welding problems of 20MnTiB which is heat treated to be more than 1000MPa in the prior art. In order to achieve the aim, the application provides a gas shielded welding method of low alloy high strength steel with the tensile strength of 1000MPa, which adopts a welding mode of gas shielded welding, and at least the welding object is a steel plate, and comprises the following steps of S10, groove processing; S20, pre-welding treatment, S30, pad welding copper pads, S40, backing welding, S50, filling welding and S60, cover welding. Preferably, in S10, the steel plate is V-beveled and has no blunt edge. Preferably, the groove angle of the V-groove is 55 °. Preferably, in S20, the pre-welding treatment is pre-welding polishing of the region to be welded and exposure of metallic luster. Preferably, in S30, the pad welding copper pad comprises a pairing and a pad copper pad, wherein the pairing gap of the steel plates is 1-1.2 mm, and the copper pad is padded on the back surface of the to-be-welded area. Preferably, S40, S50 and S60 are selected from welding wires and shielding gas, specifically: S40, S50 and S60 are all made of the same welding wire, the diameter of the welding wire is 1.2mm, and the components of the welding wire are as follows ：C 0.08-0.09、Mn 1.62-1.75、Si 0.56-0.59、Cu 0.08-0.18、Cr 0.16-0.22、Mo 0.45-0.55、Ti 0.05-0.1、P≤0.02、S≤0.01; S40, S50 and S60 all adopt the same shielding gas, and the shielding gas comprises 82% of argon and 18% of carbon dioxide. Preferably, the welding parameters of the S40 are that the welding voltage is 14-16V, the welding current is 120-140A, the gas flow is 18-20L/min, and the welding speed is 120-150 mm/min. Preferably, welding parameters of the S50 and the S60 are that the welding voltage is 22-25V, the welding current is 200-230A, the gas flow is 20-22L/min, and the welding speed is 300-360 mm/min. Preferably, the interlayer temperature of S50 and S60 is controlled to be 80-100 ℃. Preferably, the method is performed by at least an automated welding robot. The gas shielded welding method for the low-alloy high-strength