. Railway mechanical engineer . autogenous weld-ing are produced by expansion and contraction and they areespecially troublesome in welding locomotive firebox vertical cracks through several staybolt holes inbad sheets will invarialjly start trouble in the next parallelrow, the cause being checks on the water side that developand extend when contraction strains are set up at the adjacentrow. It is generally supposed that the electric welding pro-cess with its small area of heating and limited amount ofexpansion takes care of all work of this kind. While there isno doubt about it
. Railway mechanical engineer . autogenous weld-ing are produced by expansion and contraction and they areespecially troublesome in welding locomotive firebox vertical cracks through several staybolt holes inbad sheets will invarialjly start trouble in the next parallelrow, the cause being checks on the water side that developand extend when contraction strains are set up at the adjacentrow. It is generally supposed that the electric welding pro-cess with its small area of heating and limited amount ofexpansion takes care of all work of this kind. While there isno doubt about its success in a good sheet, it may fail if thesheet is checked on the water side. In the job which was finally handled as shownin the sketch, a vertical crack was found which extended con-tinuously between nine stayliolts. This was electricallywelded, and on cooling the next row of parellel bolts showeda crack eight bolts in length. On welding this row the nextone cracked for a length of four bolts. The sheet had one Bighf Side. ,^m 11 a II ^Sf^r,^Tr:^^r^^rr,^^J^^rrTi^^..i^^^i^^ Cross SecHon af Puiiing Bo/^s. Method of Applying Firebox Patch to Remove IVIechanically theShrinioge Strains riveted patch, and with this additional troulile, it was slatedfor the scrap pile. There was only one thing to do: weldin a patch and finish the sheet without leaving any shrinkagestrain. In the sketch, row A was the first one welded, B the secondand C the third. These three lines of bolts were cut outand a box patch placed as shown. Rows A and C wereflexible bolts and screwed in position to hold the patch inproper relation to the side sheet. It will be noticed that tliepatch is dished about -4 in- towards the water side whichallows 34 in. for shrinkage when the patch is brought outflush with the sheet. Over row 5 and extending the widthof the sheet were placed two parallel bars one inch by fourinches, riveted together one inch apart. Between these barsand extending into the holes
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectrailroadengineering
