For pipes and tubes

Fig. 5. Vacuum caUbrator for pipe and tubing extmsion A, molten tube from die B, tank C, hinged cover with gasket D, siting rings E, circulated and temperature controlled water E, water level G, vacuum and H, inside of pipe open to atmospheric pressure (15).

Eddy current examination of austenitic stainless steel pipe and tubing shall follow the general guidelines of ASME BPV Code Section V, Article 8, subject to the following specific requirements for pipe and tube ... 

For pipes and tubes with their parabolic velocity profile the various pulse response curves are found to be as follows ... 

It is worth noting that, although in principle tube and tubular blown film dies are similar, in practice they are quite different in function, size, and complexity. Blown film dies are much longer, have a very small die lip opening, and are subject to more stringent product uniformity criteria because there is no sizing equipment downstream. Furthermore, blown film products are almost exclusively LDPE, and occasionally HDPE and PP. On the other hand, HDPE and rigid and plasticized PVC are the common polymers for pipes and tubes. 

Figure 6.16 Typical spider-type tube die for pipe and tube extrusion.

Calibrator with ultrasonic gauging for pipe and tubing extrusion A=rubber seals B = stainless steel guides C brushes (to remove bubbles) D ultrasonic probes E water drain and water inlet. 

Because of its high tensile strength, it-poly(butene-l) is used as packaging film. It is also used for pipes and tubes because of low creep, good flexibility, and resistance to stress crazing. 

The gasket consists of a lens shaped ring of heat treated low alloy steel or some other metal. The ring should be softer than the flange face. Flardness of the conventional lens ring varies with the metal required for the service condition. This joint is ideal for pipe and tube applications. It can be used for small connections and can be used for pressure vessel closures but is better suited for piping applications. 

Figure 7-47. Examples of calibration systems for pipe and tube extrusion lines.

Figure 8.15 Vacuum sizing tank used for pipe and tube extrusion.f ...

Materials. The preferred materials for piping and tubing in contact with NO,OUT A are 304 or 316 stainless steel. The circulation and metering pumps incstainless steel construction, and the water booster pump is bronze. The storage tank is FRP, and the injectors are 316 stainless steel or Monel (Grisko, 1992). 

While 5 to 9% Cr materials are often used for pipe and tubing, pressing vessels of this composition are seldom encountered, because the required corrosion resistance is imparted to the base material by stainless cladding or weld overlays. Cr-Mo steels with this range of chromiiun do not markedly temper-embrittle and retain reasonable room-temperature toughness. 

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