In countries using the English system of measurement stress is always given in pounds per square inch (lbs per sq in.). Where the metric system is used, stress is given in newtons per square milli­meter (N/mm2), where 1 lb is 4.44822 newtons. 1000 L8S. ЮОО UBS. ,’OOOIBS. A I000LBS. 1000 LBS. В 1000 LBS. D […]

The materials used by pipe welders are primarily metals. It is, therefore, logical that a better understanding of the properties and the nature of metal will be useful in pipe welding and the objective of this chapter is to enlarge upon this subject. Metals have distinguishing characteristics that are important to know. In the solid […]

Another common orientation at which T-joints must be welded is shown in Fig. 10-8. In this case, the weld must be made in three welding positions, namely: overhead, vertical uphill, and flat, in the order given. The overhead weld is made using a slanted “loop” weave while for the other two welding positions, a slant […]

A typical T-joint is shown in Fig. 10-6. The joint must be very carefully prepared by beveling the edges so that a good fit-up is obtained. After the root bead is welded, additional filler beads are deposited to fill the joint and give it more strength. On both sides, the weld is started at the […]

When two pipes are joined together as shown in Fig. 10-5, the edges of the joint are beveled and a root bead is first deposited in the usual way to close the joint. The intermediate layers and the cover layers, however, assume the characteristics of a fillet weld. In effect, four separate joints, two on […]

The procedures shown in Fig. 10-3 are used when the pipes to be welded are at an angle, or approximately in the 6G position. In this case the joint is a butt joint. The bead is started by overhead welding at the lowest part of the pipe. As the bead progresses around the pipe, the […]

The principles of pipe welding have been treated in the last six chapters. Much emphasis has been placed on small, but important, details, such as the preparation of the pipe joint, striking the arc, the arc length, the electrode angle, and controlling the molten pool of metal. Procedures for welding root beads, intermediate layers, and […]

Steelmaking plays an important role in securing the properties need­ed for cryogenic services. It produces steels with features such as (a) fully deoxide steel (fully killed steel), (b) fine grain, (c) heat treatment, quench and tempered (d) alloy with nickel, (e) minimal use of carbon, and (f) reduction in the sulfur and phosphorus content to […]

Welding at high temperatures demands that the weldment be made of alloy steel because of two property limitations of iron and carbon steel, which grow weaker as temperature rises. These are a decrease in strength and an increase in corrosion and oxidation. Chromium and moiychrom steel, also known as chrom-moly, were originally developed for elevated […]

It would be possible to weld the root bead with the pipe nipples placed on end on a welding table. However, it may prove awkward to weld in this position, especially if the welding table is large. A better method would be to clamp the pipe nipples onto a welding stand, as shown in Fig. […]