Roll seam welding

Welded pipe is made from rolled strips formed into cylinders and seam-welded by various methods. The welds are credited with 60 to 100 percent of the strength of the pipe wall depending on welding and inspec tion procedures. Larger diameters and lower ratios of wall thickness to diameter can be obtained in welded pipe than can be... 

Most liquid collectors used with high-performance solar dryers are made with a finned metal tube absorber. The absorbers applied to solar hot water producing systans are often made of sheet halves with stamped passages bonded by seam welding or by rolling them together (Figure 14.22a). 

T vo basic methods of RPV fabrication have been used. The first method used rolled and welded plates to form separate shell courses. Thus, an RPV fabricated in this manner has both longitudinal (axial) and circumferential (girth) weld seams. In some of the older (pre-1972) PWR RPVs, these longitudinal seams are of particular concern for RPV integrity due to high levels of Cu in the welds. All BWR and most of the PWR RPVs used this rolled and welded plate construction. 

During the Vietnam war, a machine was designed to transport water, gas, and jet fuels to the front. Rolled steel or aluminum tanks were bulky, awkward, and required seam welding, a skilled operation. A pultrusion machine was installed in a standard 12-m highway trailer, and a composite tank constructed on-site (28). 

Vessels for vacuum service are normally preferred to be fabricated by seamless wall construction to avoid a possible incidence of crevices where particles, soiled solvent, and rinse fluid can be trapped Yet as noted above, seamless pipe and tubing are not available to fabricate vessels in sizes desired for enclosed cleaning machines Consequently, these vessels, such as those shown in Figures 2 19 through 2 26, are fabricated not from pipe or tubing but from stainless steel plate which is rolled to shape, seam welded to size, and then precision ground to achieve a desired internal surface finish. 

The images of vessels in Table 4.6 are those holding the same volume of adsorbent. Where necessary to achieve the design goal of 150 ft/min vapor velocity, additional outside air is added. The activated carbon used for all cases is the same — derived from coconut husks and with an internal pore diameter of 1.34 nm (Appendix A2). All of the vessels proposed for use in Table 4.7 must be fabricated from a sheet of carbon steel which has been rolled and seam-welded. Available pipe sizes are too small for use. 

Seams. As defects, seams are distinct from weld seams and may be found in nonwelded (seamless) tubes. They are caused by crevices that have been closed by some rolling process but remain unfused. 

Seams. As a defect, a seam is distinct from the seam resulting from a welding process. Seam defects can be found in nonwelded (seamless) tubes. They can originate from blow holes or nonmetallic inclusions in the ingot and are caused by crevices that have been closed by some rolling process but remain unfused. At times, they will appear in a spiral pattern in tubes. Seams can be very tight and appear as hairlines on the surface. They can cause failure when the component is pressurized. 

Cylindrical sections are usually made up from plate sections rolled to the required curvature. The sections (strakes) are made as large as is practicable to reduce the number of welds required. The longitudinal welded seams are offset to avoid a conjunction of welds at the comers of the plates. 

Center of the U.S. Bureau of Mines. The radon chamber in Denver Research Center is designed to provide adjustable humidities and a well controlled, monitored radon and CN concentration. It has a length of 213 cm, a diameter of 152 cm, and a volume of about 3.89 m. The walls are made of 0.5-cm rolled steel with welded seams. Figure 1 shows the general scheme of the test chamber excluding the transducers and data aquisition system. 

Spiral weld pipe is made from strip in coil form. After the strip is uncoiled, it proceeds to a trimmer and then to forming rolls that shape it into spiral form. The spiral seam is submerged arc welded automatically and continuously—first on the... 

A submerged-arc process is commonly used for welding stainless steels and carbon steels when an automatic operation is acceptable. The electrode is a continuous roll of wire fed at an automatically controlled rate. The arc is submerged in a granulated flux which serves the same purpose as the coating on the rods in the shielded-arc process. The appearance and quality of the submerged-arc weld is better than that obtained by an ordinary shielded-arc manual process however, the automatic process is limited in its applications to main seams or similar long-run operations. 

The body blank is formed into a cylinder over a mandrel and the hooks are engaged and rolled closed to form the side seam, which is then soldered or welded. A recent development consists of making a cylinder long enough for three bodies, which is parted across previously made score lines into three separate can bodies. Speeds of up to 900 bodies per minute can be achieved, compared with around 500 for the conventional method. 

Formerly the edges of the heated blank were welded upon the mandrel by the successive blows of a trip-hammer, or a dit)p, dies intervening between the iron tube and the drop and anvil respectively. A portion only of the seam is closed at a time by this means, and the o[ieration is more tedious an l expensive than the rollers just described. The rolling process was introduced from England. 

Figure 9.33 From the left spot-welded standing seam, projection-welded bolt, reinforced rolled edge. (Reproduced with permission from Wesfarmers Chemicals, Energy Fertilisers.)...

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