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US-12617044-B2 - Solid wire for gas metal arc welding

US12617044B2US 12617044 B2US12617044 B2US 12617044B2US-12617044-B2

Abstract

Provided is a solid wire for gas metal arc welding, solid wire being suitable as a welding material for high-Mn steel materials and generating less fume during welding. The solid wire of the present invention has a composition containing, in mass %, C: 0.20 to 0.80%, Si: 0.15 to 0.90%, Mn: 15.0 to 30.0%, P: 0.030% or less, S: 0.030% or less, Al: 0.020% or less, Ni: 0.01 to 10.00%, Cr: 6.0 to 15.0%, Mo: 0.01 to 3.50%, O: 0.010% or less, N: 0.120% or less, and the balance being Fe and incidental impurities.

Inventors

  • Atsushi Takada
  • Keiji Ueda

Assignees

  • JFE STEEL CORPORATION

Dates

Publication Date
20260505
Application Date
20210713
Priority Date
20200803

Claims (10)

  1. 1 . A solid wire for gas metal arc welding, the solid wire comprising a composition that contains, in mass %, C: 0.20 to 0.80%, Si: 0.15 to 0.90%, Mn: 15.0 to 30.0%, P: 0.030% or less, S: 0.030% or less, Al: 0.020% or less, Ni: 0.01 to 10.00%, Cr: 6.0 to 15.0%, Mo: 0.01 to 3.50%, O: 0.010% or less, N: 0.120% or less, and the balance being Fe and incidental impurities.
  2. 2 . The solid wire for gas metal arc welding according to claim 1 , wherein the composition further contains at least one selected from the groups A and B, in mass %, Group A: at least one selected from V: 1.0% or less, Ti: 1.0% or less, and Nb: 1.0% or less; and Group B: at least one selected from Cu: 1.00% or less, Ca: 0.010% or less, and REM: 0.020% or less.
  3. 3 . A gas metal arc welding method comprising welding a high-Mn steel having a Mn content of 10 to 35% by gas metal arc welding in accordance with JIS Z 3930-2013 using a solid wire for gas metal arc welding and using, as a shielding gas, a mixed gas containing 10 to 40% CO 2 and the balance being an inert gas Ar at a welding current of 180 to 330 A at a fume generation amount of 1200 mg/min or less, the solid wire having a composition that contains, in mass %, C: 0.20 to 0.80%, Si: 0.15 to 0.90%, Mn: 15.0 to 30.0%, P: 0.030% or less, S: 0.030% or less, Al: 0.020% or less, Ni: 0.01 to 10.00%, Cr: 6.0 to 15.0%, Mo: 0.01 to 3.50%, O: 0.010% or less, N: 0.120% or less, and the balance being Fe and incidental impurities.
  4. 4 . The gas metal arc welding method according to claim 3 , wherein the composition further contains, at least one selected from the groups A and B, in mass %, Group A: at least one selected V: 1.0% or less, Ti: 1.0% or less, and Nb: 1.0% or less; and Group B: at least one selected from Cu: 1.00% or less, Ca: 0.010% or less, and REM: 0.020% or less.
  5. 5 . The gas metal arc welding method according to claim 4 , wherein a weld joint formed by the gas metal arc welding method exhibits excellent low-temperature toughness of an absorbed energy of 28 J or more in a Charpy impact test at a test temperature of −196° C., and high strength of a room-temperature tensile strength of 400 MPa or more.
  6. 6 . The gas metal arc welding method according to claim 3 , wherein a weld joint formed by the gas metal arc welding method exhibits excellent low-temperature toughness of an absorbed energy of 28 J or more in a Charpy impact test at a test temperature of −196° C., and high strength of a room-temperature tensile strength of 400 MPa or more.
  7. 7 . A method for producing a weld joint by using the gas metal arc welding method according to claim 4 .
  8. 8 . A method for producing a weld joint by using the gas metal arc welding method according to claim 4 .
  9. 9 . A method for producing a weld joint by using the gas metal arc welding method according to claim 6 .
  10. 10 . A method for producing a weld joint by using the gas metal arc welding method according to claim 5 .

Description

CROSS REFERENCE TO RELATED APPLICATIONS This is the U.S. National Phase application of PCT/JP2021/026319, filed Jul. 13, 2021 which claims priority to Japanese Patent Application No. 2020-131365, filed Aug. 3, 2020. FIELD OF THE INVENTION The present invention relates to solid wires for gas metal arc welding, and particularly relates to a solid wire for welding high-Mn steel materials used in cryogenic environments. BACKGROUND OF THE INVENTION Environmental regulations have been strengthened in recent years. Liquefied natural gas (hereinafter, also referred to as LNG), which does not contain any sulfur, is regarded as a clean fuel that does not generate air pollutants such as sulfide oxides. Accordingly, the demand on LNG is increasing. To transport or store LNG, a container (tank) for transporting or storing LNG is required to maintain excellent cryogenic impact toughness at a temperature of −162° C., which is the liquefaction temperature of LNG, or less. Due to the necessity to maintain excellent cryogenic impact toughness, aluminum alloys, 9% Ni steels, austenite stainless steels, etc., have been used as materials for the containers (tanks) and the like. However, aluminum alloys have a low tensile strength and pose problems in that the structure needs to be designed to have a large thickness. Furthermore, aluminum alloys have a poor weldability. In addition, 9% Ni steel is economically disadvantageous because use of an expensive Ni-based material as a welding material is required. Furthermore, austenite stainless steel is expensive and has a problem of low base material strength. Because of these problems, application of high-Mn-content steel (hereinafter, also referred to as high-Mn steel) having a Mn content of about 10% to 35% in mass % to the material for containers (tanks) for transporting or storing LNG has recently been studied. The features of the high-Mn steel are that the high-Mn steel is in an austenite phase even at cryogenic temperatures, thereby preventing brittle fracture, and has high strength compared to austenite stainless steel. Therefore, development of a welding material with which such high-Mn steel materials can be welded stably has been demanded. To meet this demand, for example, Patent Literature 1 proposes “a high-strength weld joint having excellent cryogenic impact toughness and a wire for flux cored arc welding therefor”. The flux cored wire for arc welding described in Patent Literature 1 has a composition containing, in weight %, C: 0.15% to 0.8%, Si: 0.2% to 1.2%, Mn: 15% to 34%, Cr: 6% or less, Mo: 1.5% to 4%, S: 0.02% or less, P: 0.02% or less, B: 0.01% or less, Ti: 0.09% to 0.5%, N: 0.001% to 0.3%, TiO2: 4 to 15%, a total of at least one selected from SiO2, ZrO2, and Al2O3: 0.01% to 9%, a total of at least one selected from K, Na, and Li: 0.5% to 1.7%, at least one of F and Ca: 0.2% to 1.5%, and the balance being Fe and incidental impurities. When welding is performed using the flux cored wire for arc welding described in Patent Literature 1, it is possible to effectively obtain a weld joint having excellent low-temperature toughness of an absorbed energy of 28 J or more in a Charpy impact test at a test temperature of −196° C. and high strength of a room temperature tensile strength of 400 MPa or more. In addition, the wire composition is adjusted to Mo: 1.5% or more, and a weld joint having excellent hot crack resistance can be securely obtained. PATENT LITERATURE PTL 1: JP 2017-502842 A SUMMARY OF THE INVENTION However, according to the study conducted by the inventors of the present invention, the technique described in Patent Literature 1 has a problem that a large amount of fume is generated during welding. Therefore, a welder is exposed to an environment containing a large amount of fume. An object according to aspects of the present invention is to address the problems of the related art mentioned above by providing a solid wire for gas metal arc welding which generates less fume during welding, suitable as a welding material for high-Mn steel materials used in cryogenic environments and enabling manufacture of a weld joint that has both high strength and excellent cryogenic toughness. Here, “generating less fume during welding” means that, when gas metal arc welding is performed in accordance with JIS Z 3930-2013 with a shielding gas composition of 80% Ar+20% CO2 and a welding current of 250 A, the fume generation amount is 1200 mg/min or less. Furthermore, “high strength” means that the room-temperature yield strength (0.2% proof stress) of a deposited metal prepared in accordance with JIS Z 3111 is 400 MPa or more, and “excellent cryogenic toughness” means that a deposited metal prepared in accordance with JIS Z 3111 has an absorbed energy vE−196 of 28 J or more in a Charpy impact test at a test temperature of −196° C. The inventors have first intensively studied factors that affect the fume generation amount during gas metal arc welding. As a result, the inv