Taking Class600, 20in all welded valve body pipeline pneumatic ball valve 44mm thick cylindrical valve body welded joint as an example, according to API 1104 Appendix A and DNV-OS-401 standard and CTOD test results, it is sufficient to assess that the submerged arc welding joint can be free of post weld heat treatment.

Advantages of non-metallic tetrafluoro compensator and its device requirements
1. No reverse thrust: Since the main material is fiber fabric, it is unable to transmit. The use of fiber compensator can simplify the design, prevent the use of large bearings, and save a lot of data and labor.
2. Vibration attenuation and isolation: fiber fabrics and insulation cotton have the functions of sound absorption, vibration isolation and transmission, which can effectively reduce the noise and vibration of boiler, fan and other systems.
3. The non-metallic compensator has good high temperature resistance and corrosion resistance: the selected fluoroplastic and silicone materials have good high temperature resistance and corrosion resistance.
4. The non-metallic compensator has excellent corrosion resistance and plays an important role in the chemical industry. For example, polytetrafluoroethylene/rubber compensators are resistant to common chemicals and solvents, especially in dilute sulfuric acid, hydrochloric acid and hydrofluoric acid escort pipelines, which cannot be replaced by metal compensators.
5. Non metallic compensators are also used in the automotive industry. For example, the indispensable rubber compensator for sealing and dust-proof in the installation of locomotive internal combustion engine brake is the rubber compensator for the air pipe sealing connection in the supply system of the tractor starter. The cold resistant, shrink resistant and permanent deformation resistant water sealed FPM rubber compensator is used in Santana, and the tetrafluoroethylene compensator fully displays the sealing characteristics of the non-metallic compensator.
6. The good comprehensive performance of non-metallic compensator makes it widely used in many engineering fields. The ventilation, dust removal, smoke exhaust and air conditioning insulation pipes and equipment with low working pressure usually use the Pingcheng compensator.