When the pipes are in a vertical position, the welding procedure used is essentially that which is used for horizontal welding and for this reason this chapter is entitled, “Horizontal Pipe Welding.” Horizontal pipe welding presents a few difficulties that are charac­teristic of welding in the 2G position. The molten metal in the puddle constantly […]

When the pipe joint is filled almost to the surface, a pipe weld is ready to be capped, using the downhill technique and stringer beads. The bevel edge should be visible on both sides to serve as a guide for depositing straight stringer beads side by side, as the weld is complet­ed. When the first […]

Filler passes that are deposited on heavy-wall pipes used in cross­country pipelines are welded by using stringer bead sequences. On the next page the diagram shows that the first three passes are single layer deposits, each extending across the bevel. The second diagram shows all the completed sequences. Pipeline welds that use the stringer sequences […]

These pipes are known for their higher strength. These low alloy, higher strength pipe require the use of certain higher strength elec­trodes that include E-8010, E-7010, and E-7048. The last of these is a low-hydrogen electrode used for downhill welding. In all cases pre­heating to specified temperature of interpass temperatures is required. The technique to […]

The author originally planned to add a new chapter about downhill pipe welding, addressing the changes that have taken place over the years in the construction of cross-county pipelines, including the needed changes in welding procedures. After considering ways to incorporate the original text on downhill welding, it seemed the best approach was to complement […]

4 ELECTRODE MOTION FOfi 12-TO 5 O’CLOCK POSITIONS Courtesy of the Hobart Brothers Co. Fig. 8-29. Weaves used to weld the cover pass. A. Slant weave used for 12 to 5 o’clock positions. B. Horseshoe weave used for 5 to 6 o’clock positions. Poor Fit-up. When a poor fit-up is encountered, the necessary corrective action […]

• REMOVE SLAG FROM CRATER AND TWO INCHES OF BEAD. the electrode downward, away from the keyhole, as shown in Fig. 8-19. This will prevent slag from mixing with unsolidified weld metal to form slag inclusions. Before restarting to weld the bead, the slag must be removed from the bead and also from about 2 […]

When the pipe nipples are correctly spaced and aligned, they are ready to be welded together (see Fig. 8-7). For welding the tack welds and the root bead, an E6010, Е6010ЇР, or E7010-A elec­trode should be used. When the wall thickness of the pipe is % inch, or less, a Vg-inch electrode is used; for […]

Thin-wall pipe can be welded by the downhill weld method. Downhill welding is very fast and economical; consequently, it is used extensively to weld cross-country pipelines. In the majority of cases, the wall thickness of the pipes used for cross-country pipelines is within the range of thickness that can be welded by this method. High-quality […]

Very high-quality pipe joints can be made using the uphill weld­ing method to weld both large — and small-diameter thin-wall pipe. It is recommended for welding high-alloyed pipe and in other cases where only the highest-quality welded joint will be accepted. For large-diameter pipe, the procedure is exactly the same as that described in Chapters […]