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SELECTION OF THE WELDING METHOD AND FILLER MATERIAL DURING THE REPAIR OF BRASS PROPELLERS

For many years the shipyards have been repairing propellers of LMtsZh-53-3-1 brass by means of gas and manual arc welding with a carbon electrode on using filler-metal rods of brass of the same mark coated with a four component flux having the composition: 50 percent KCl, 12.5 percent NaCl, 35 percent cryolite, 2.5 percent charcoal. However, these methods are far from perfect: during gas welding considerable deformations arise, while during manual arc welding cracks form and there occurs considerable burnout of metal (36-40 percent even under optimal conditions). Moreover, welding with a carbon electrode is a highly unproductive technique. To eliminate these shortcomings, methods of electric arc welding were tested out on using Br.AMts9-2 aluminum bronze as the filler metal. Experience in the repair welding of 5-7 m diameter propellers of large-tonnage ships has shown that the use of rods and wire of this bronze is warranted: it has become possible to weld up cracks and to join vane parts with welds reaching as much as 150 mm in thickness without risking crack-formation. Moreover, the structure of the weld metal, the fusion line and the near-weld zone then are finegrained, without pores, cracks or other defects. It was established that when Br. AMts9-2 bronze is used as the filler metal, the optimal composition of the flux should be: 66 percent cryolite, 25 percent KCl, 6 percent NaCl, and 3 percent charcoal. Further, electric arc welding in lieu of gas welding was found to improve quality, reduce internal stresses and reduce to a minimum the deformations of propellers. Moreover, considering that LMtsZh 53-3-1 brass is prone to stress corrosion cracking owing to residual stresses, these stresses can be relieved by means of local heat treatment (by placing a furnace under the affected parts of the propeller vanes); subsequent prolonged operation of the propellers has confirmed that skillfully conducted local heat treatment indeed relieves dangerous residual stresses.

  • Authors:
    • Pashkov, A P
    • Kipernik, YeG
    • Kudryashev, M M
    • Yavorskiy, I A
  • Publication Date: 1968

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Filing Info

  • Accession Number: 00014965
  • Record Type: Publication
  • Source Agency: Joint Publications Research Service
  • Files: TRIS
  • Created Date: May 7 1971 12:00AM