Seamless Tubing

Manufacturing tolerances for steel, stainless-steel, and nickel-alloy tubes are such that the tubing is produced to either average or minimum wall thickness. Seamless carbon steel tube of minimum wall thickness may vaiy from 0 to 20 percent above the nominal wall thickness. Average-wall seamless tubing has an allowable variation of plus or minus 10 percent. Welded carbon steel tube is produced to closer tolerances (0 to plus 18 percent on minimum wall plus or minus 9 percent on average wall). Tubing of aluminum, copper, and their alloys can be drawn easily and usually is made to minimum wall specifications. 

Defects in finished components can sometimes be traced as far back as casting problems in the ingot or billet from which the component was eventually produced. Defects in welded tubes may be linked to defective metal or to the welding process itself Defects in seamless tubes can originate in extrusion or drawing processes. 

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. 

Sample Specifications 1 in. (2.5 cm) outside diameter, 90 10 cupronickel seamless tube... 

Welded or seamless tubing manufactured in a large range of sizes of varied chemical compositions (sizes range V16-IO % in. o.d. inclusive for carbon and alloy material) usually not fabricated to meet any specification other than application requirements fabricated to meet exact outside diameter and decimal wall thickness. 

Unalloyed molybdenum is available commercially in almost all forms, from forging billets and plate to seamless tubing, foil and wire. In addition, the following molybdenum-base alloys can be considered as established engineering materials Mo-0-5Ti-0-8Zr (designated TZM) and Mo-30W. A Mo-30Ta alloy has also been produced for specific applications where high corrosion resistance is required. 

Drawing Tantalum has a tendency to gall and is normally anodised to provide a surface which will carry a drawing lubricant. Seamless tube is produced by cupping followed by drawing or by hollow shells. 

The design of pipework has to be such as to allow access to welds and bends for weld and surface preparation. It is preferable to use seamless tubing conforming to BS 806 1986. Where this is impractical, tubing in accordance with BS 1387 1985 is acceptable provided that the butt-welded joint seam does not restrict the bore by more than 0-25 mm. 

B 210 Aluminum and Aluminum-Alloy Drawn Seamless Tubes... 

For display shells of 200 mm and above, reinforced fibreglass mortar tubes are invariably used. Welded steel tubes have long been considered to be amongst the safest because, in the event of a pressure-burst, the tube will split in the vicinity of the weld, thus creating a predictable danger zone. With seamless tubes the fragmentation is completely random and creates a shrapnel hazard for the fireworks operator. 

ISO 2604-2, Steel products for pressure purposes — Quality requirements — Part 2 Wrought seamless tubes. 

RESISTANCE TO HYDROGEN - INDUCED CRACKING IN COMMERCIAL 7"0 SEAMLESS TUBE STEEL... 

The fabrication from seamless tubing is described in Section 10.1. 

Figure 1 shows a schematic view of the tubular reactor. Seamless tubing, of 1/4-inch OD, type 316 stainless steel, was used for the preheater and the reactor. The reactor itself was 187 feet long, wound into a helix of 1 ft. diameter. The reactor and preheater were immersed in separate drums, which were filled with water, and maintained at constant temperature. 

Bearing element of a sorber design is the container (pressure vessel), where the other sorber elements are placed. As a rule, the container is made of a seamless tube with welded bottom. Sorber should be orientated so that its long axis was normal to a gravity vector for avoiding vessel wall "swelling" in the bottom part. 

The HPS condenser is made of 316L seamless tubes with a nominal outer diameter of 25 mm, a nominal wall thickness of 2.2 mm and a length of 6.4 m. The tube ends are joined to the tube sheet (100 mm thick) to form a bundle 1.1 m in diameter that is welded to the shell to make up the shell-and-tube condenser. The tubes are weld sealed at the top of the tube sheet as shown in Figure 7.72. The condenser is installed vertically with severe operating conditions1 at the inlet of the top tube sheet as the temperature reaches 150°C and pressure 250 psi. 

---