Welding; theory, practice, apparatus and tests, electric, thermit and hot-flame processes . Fig. 54.—Top section of broken crank, case with broken arms. with double riveting, as seven to twelve. The cost of tripleriveting is not given, but it would still further increase the discrep-ancy. Besides being cheaper, the acetylene-weld is absolutelyleak proof, a great advantage over a riveted joint. On the other hand, an apparently sound acetylene-weld mayhave a tensile strength of 25 per cent, instead of 95, and may becrystalline and brittle; whereas the riveted joint is of certain HOW TO WELD 107
Welding; theory, practice, apparatus and tests, electric, thermit and hot-flame processes . Fig. 54.—Top section of broken crank, case with broken arms. with double riveting, as seven to twelve. The cost of tripleriveting is not given, but it would still further increase the discrep-ancy. Besides being cheaper, the acetylene-weld is absolutelyleak proof, a great advantage over a riveted joint. On the other hand, an apparently sound acetylene-weld mayhave a tensile strength of 25 per cent, instead of 95, and may becrystalline and brittle; whereas the riveted joint is of certain HOW TO WELD 107 Strength. In the present state of the art it would be a mistaketo advocate the acetylene-welding of boilers of any size, though forsmall containers and tubes that can be rolled and annealed theriveted and brazed joint is being rapidly superseded by theacetylene-weld. But oxy-acetylene repair welds are now fre-quently made on cracked and corroded boilers. Cracks are. Fig. 55.—Engine crank case with welded arms. first laid open by a partial heating, until their full extent isknown. Then they are welded by the flame and a melt bar,working up from the bottom of the crack. Where the plate isfull of cracks or is corroded deeply, a section of the plate is cutout with a cutting flame and a fresh plate patch is welded repairing requires very careful preheating, hammering of io8 AVELDING the weld and subsequent annealing of the plate surroundingthe weld. Repairing Defective Castings.—One of the importantpossibilities of this process is in the repairing of defective castingsfresh from the foundry. Even in the most careful foundry prac-tice the scrap heap is always a very expensive mountain to thefoundry man. If he can keep down the heap he can increase hisprofits. With the oxy-acetylene flame all kinds of defects of
Size: 1286px × 1942px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublishernewyo, bookyear1910
