| 摘要 |
997,934. Welding by fusion. SHIN-MITSUBISHI JUKOGYO KUBUSHIKI KAISHA. March 23, 1962 [Dec. 30, 1961], No. 11178/62. Heading B3R. In tandem arc-welding the trailing bead is deposited on the leading bead when the latter has solidified and cooled to a temperature such that martensite is in the process of being precipitated. The welding parameters used in depositing the leading bead are selected to produce a cooling rate of the bead such as to produce a structure consisting of ferrite, a transitional structure and martensite with or without pearlite. The plates being welded may be of Mn-Si steel or of a steel containing 0À99% Mn, 0À26% Si, 1.57% Ni and 0À3% Mo. The weld may contain one or more of 1-1À5% Mn, 0À3-0À5% Si, 0À5-4% Ni, 0À1-0À5% Cr and 0À1-0À5% Mo. A preliminary bead 7 containing alloying ingredients may be deposited by a submerged arc-welding head 6, the alloying ingredients being in the electrode 8 and/or the flux 4. The flux is picked up by a device 9 and the bead 7 is completely remelted by a carbon dioxide shielded metal arc-welding head 10 to deposit the leading bead 11. After cooling at a rate and to a temperature as described above, the leading bead 11 is covered by a trailing bead 12 produced by a consumable electrode of a submerged arc-welding head 16. The upper portion of the leading bead 11 is remelted but the lower and major part -is reheated to a temperature such that subsequent cooling produces a tempering effect. The trailing bead 12 is cooled at a similar rate to the leading bead. The submerged arc-welding head 6 may be dispensed with. |
