Railway and Locomotive Engineering . r cent, the op- fs^pv *? m~M 1 - f^^ ..^^p^ FIG. 1. BROKEN SECTIONS OF CAST IKON AIR COMPRESSOR BACK FRAME LINED UP FOR WELDING. erators decided to repair it by means ofThermit welding. In welding the cast-ing the bed plate was laid on its side, asshown in Fig. 1. The broken sections ofthe casting were then lined up by meansof bolted straps, as shown, a small gapbeing left between the two sections to pro-vide space for the Thermit steel later t(ienter. Yellow pattern wax was then insertedin the space and a mold formed aroundthe wax. A preheating torch was d
Railway and Locomotive Engineering . r cent, the op- fs^pv *? m~M 1 - f^^ ..^^p^ FIG. 1. BROKEN SECTIONS OF CAST IKON AIR COMPRESSOR BACK FRAME LINED UP FOR WELDING. erators decided to repair it by means ofThermit welding. In welding the cast-ing the bed plate was laid on its side, asshown in Fig. 1. The broken sections ofthe casting were then lined up by meansof bolted straps, as shown, a small gapbeing left between the two sections to pro-vide space for the Thermit steel later t(ienter. Yellow pattern wax was then insertedin the space and a mold formed aroundthe wax. A preheating torch was directedinto the mold for the purpose of dryingout the mold, preheating the sections tobe welded and burning out the patternwax. Finally when everything was ready tomake the weld 300 lbs. of Cast Iron Ther-mit, a mixture of iron oxide and alumi-num, to which was added 3 per cent FerroSilicon 50/50 per cent and 20 per centmild steel punchings, were ignited in acrucible suspended over the mold. Achemical reaction at the extremely hot. FIG. 2. THERMIT WELDED FRAMEBEFORE REMOVING RISER. temperature of 5000° Fahr. was startedduring which the aluminum combinedwith the oxygen of the iron oxide to formaluminum oxide or slag, in a highly super-heated molten state while the iron wasset free and produced as liquid steel. The reaction required only about 35seconds at the end of which time theliquid steel which had precipitated to thebottom of the crucible was tapped throughthe bottom of the crucible into the mold,thus amalgamating with the broken sur-faces of the two sections. The metal in the weld was allowed tocool slowly after which the mold materialwas removed, excess metal cut off and thewelded bed plate returned to service, asshown in Fig. 3, as strong as ever. The function of the steel riser shown ^ ^J k 0 Shops of the EriePa. in Fig. 2 was to hold a supply of steelwhich would remain a consider-able period of time and take care of allshrinkage, so that when a pipe is form
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Keywords: ., bookcentury1900, bookdecade1900, bookpublishernewyork, bookyear19
