# US 8,785,806 B2 · Submerged arc welding method with multiple electrodes for steel material > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,785,806 B2 - Document ID: US8785806B2 - Status: Granted - Kind: B2 - Application number: 12/918,095 - Filed: 2009-02-19 - Published: 2011-02-17 - Granted: 2014-07-22 - Earliest claimed: 2008-02-22 - Assignees: Jfe Steel Corporation - Applicants: Atsushi Ishigami; Kenji Oi; Naoya Hayakawa - Inventors: Atsushi Ishigami; Kenji Oi; Naoya Hayakawa - Web page: https://patentgrep.com/patent/US8785806B2 ## CPC - B23K 9/188: {making use of several electrodes} - B23K 9/0253: {for the longitudinal seam of tubes} - B23K 9/0282: {for welding tube sections} - B23K 2101/06: Tubes - B23K 2103/04: Steel {or steel} alloys - B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM ## Abstract Steel is subjected to multiple-electrode submerged arc welding with three or more electrodes in which a direct-current power source is used to supply current to a first electrode, the welding by the first electrode is carried out at a current density of 250 A/mm2 or more, preferably with a wire diameter of 3.2 mm or less and a weld current of 1,000 A or more, the welding by the second electrode is carried out at a current density of 150 A/mm2 or more, preferably with a weld current of 600 A or more, one of the interelectrode spacings is 23 mm or more on a surface of the steel, and the remaining interelectrode spacings are 20 mm or less. ## Claims ### Claim 1 A multiple-electrode submerged arc welding method for steel, comprising: spacing one of the interelectrode distances to 23 mm or more on a surface of the steel; spacing the remaining interelectrode distances to 20 mm or less on the surface of the steel; supplying current to a first electrode using a direct current power source; supplying current in which the current density of the first electrode is 250 A/mm2 or more and the current density of a second electrode is 150 A/mm2 or more; subjecting steel to multiple-electrode submerged arc welding with three or more electrodes; and forming a semi-one molten pool that is a molten pool partially constricted and shallow at a bottom surface of the molten pool and has a shape like a bottle gourd such that two front and rear molten pools are fused together. ### Claim 2 (depends on 1) The method according to claim 1, wherein current of the first electrode is 1,000 A or more and current of the second electrode is 600 A or more. ### Claim 3 (depends on 1) The method according to claim 1, wherein welding by the first electrode is carried out with a wire diameter of 3.2 mm or less. ### Claim 4 (depends on 1) The method according to claim 1, wherein the wire center-to-center spacing between the first electrode and the third electrode is 40 to 60 mm on a surface of the steel, and a current ratio of the first electrode (I1) to the second electrode (I2) satisfies the following inequality: I2/I1≧0.5 where I1 is current (A) of the first electrode and I2 is current (A) of the second electrode. ### Claim 5 (depends on 1) The method according to claim 1, wherein four electrodes are used and the wire center-to-center spacing between the third electrode and the fourth electrode is 20 mm or less on a surface of the steel. ### Claim 6 (depends on 1) The method according to claim 1, wherein each of inner and outer surfaces of the steel is subjected to one-layer welding. ### Claim 7 (depends on 2) The method according to claim 2, wherein welding by the first electrode is carried out with a wire diameter of 3.2 mm or less. ### Claim 8 (depends on 2) The method according to claim 2, wherein the wire center-to-center spacing between the first electrode and the third electrode is 40 to 60 mm on a surface of the steel, and a current ratio of the first electrode (I1) to the second electrode (I2) satisfies the following inequality: I2/I1≧0.5 where I1 is current (A) of the first electrode and I2 is current (A) of the second electrode. ### Claim 9 (depends on 3) The method according to claim 3, wherein the wire center-to-center spacing between the first electrode and the third electrode is 40 to 60 mm on a surface of the steel, and a current ratio of the first electrode (I1) to the second electrode (I2) satisfies the following inequality: I2/I1≧0.5 where I1 is current (A) of the first electrode and I2 is current (A) of the second electrode. ### Claim 10 (depends on 7) The method according to claim 7, wherein the wire center-to-center spacing between the first electrode and the third electrode is 40 to 60 mm on a surface of the steel, and a current ratio of the first electrode (I1) to the second electrode (I2) satisfies the following inequality: I2/I1≧0.5 where I1 is current (A) of the first electrode and I2 is current (A) of the second electrode. ### Claim 11 (depends on 2) The method according to claim 2, wherein four electrodes are used and the wire center-to-center spacing between the third electrode and the fourth electrode is 20 mm or less on a surface of the steel. ### Claim 12 (depends on 3) The method according to claim 3, wherein four electrodes are used and the wire center-to-center spacing between the third electrode and the fourth electrode is 20 mm or less on a surface of the steel. ### Claim 13 (depends on 4) The method according to claim 4, wherein four electrodes are used and the wire center-to-center spacing between the third electrode and the fourth electrode is 20 mm or less on a surface of the steel. ### Claim 14 (depends on 7) The method according to claim 7, wherein four electrodes are used and the wire center-to-center spacing between the third electrode and the fourth electrode is 20 mm or less on a surface of the steel. ### Claim 15 (depends on 10) The method according to claim 10, wherein four electrodes are used and the wire center-to-center spacing between the third electrode and the fourth electrode is 20 mm or less on a surface of the steel.