Guide for selecting valve materials for dry chlorine environment
The guide for selecting valve materials under dry chlorine environment is as follows:
The product type | parts | I and the IV level | Class II and V | Level III and VI |
The casting | Body and bonnet | A216 gr.WCB, WCC,A395,A352 gr.LCB | ASTM A352Gr.LCB, LCC,A352 Gr.LC1,A352 Gr.LC2 | ASTM A352Gr. LC3 |
forgings | Body and bonnet | ASTM A105,A181 CI60, 70,A182 gr. F1,A350 gr. LF1 | ASTM A350 Gr. LF2 | ASTM A350 Gr. LF3 |
Plate and profile | Body and bonnet | ASTM A516 Gr. 70 | ASTM A516 gr.55, 60, 65(impact test -46℃) | ASTM A203 gr.e (impact test -101℃) |
Middle way fasteners | bolt | ASTM A193 Gr. B7 | ASTM A320 gr.L7 (impact test -101℃) | ASTM A320 gr.L7 (impact test -101℃) |
nut | ASTM A194 Gr.2H, heavy-duty hexagon | ASTM A194 gr.4, heavy-duty hexagon nut (impact test -101℃) | ASTM A194 gr.4, heavy-duty hexagon nut (impact test -101℃) | |
Other metal parts | The valve stem | Hastelloy C22, c-276,Monel 500,Monel 400,R405 | Hastelloy C22, c-276,Monel 500,Monel 400,R405 | Hastelloy C22, c-276,Monel 500,Monel 400,R405 |
Ball, cock, disc | Monnel 400 | Monnel 400 | Monnel 400 | |
Corrugated pipe | Monel 400, R405, Hastelloy C - 276 | Monel 400, R405, Hastelloy C - 276 | Monel 400, R405, Hastelloy C - 276 | |
Non-metallic component | Seat, sleeve, seal ring | Teflon | Teflon | Teflon |
packing | Flexible graphite or Teflon | Teflon | Teflon | |
Tathagata gasket | Teflon | Teflon | Teflon |
Note:
1. ASTM A395 for ductile iron can be used in chlorine medium class I.
2. The corrosion resistance of Hastelloy C and Hastelloy c-276 is better than Monel.
3. Monel 400, ASTM B564 for forgings, and ASTM B127 for plates.
4. To prevent the double corrosion of chemical and physical corrosion, the hard seal is usually Stellite 21 or Stellite 6. The Monel K500 is also a good hard seal material.
5. Other parts (such as bracket, bracket nut, packing gland, packing sleeve, stud, and handwheel) shall be suitable for working conditions as agreed by both parties. Fasteners shall not use 300 series of stainless steel.
6. Hastelloy C22 and Hastelloy c-276 are integral stems, which can resist the corrosion caused by the combination of the medium escaping from the packing and the moisture in the air, improving the availability.
7. PTFE is limited to one fully closed connection.
8. The bellows shall be designed to ensure that the service life of the bellows can meet the requirement of 1000 operation cycles under the maximum working pressure at ambient temperature.
9. Wound gaskets Monel 400 and Hastelloy c-276 with polytetrafluoroethylene or flexible graphite.
10, although do not recommend the use of asbestos in packing or the Tathagata gasket, but often used on some of the valves before you can see, in this case, only have been familiar with operational procedures and technical personnel to be allowed to operate the asbestos, and should be as little as possible contact and application of asbestos, albeit on some old valves.
11. After a long period of use by the end-user, it was found that the 316/316l valve (ASTM A351/A744 Gr CF8M/CF3M) could be used under certain conditions, but the material of the newly invested valve must be thoroughly tested and evaluated.
12. Castings must be traceable and conform to ASTM standards.
13. ASTM A194 Grade gr. 2H or 2HM nuts may be substituted.
14. Can not use stainless steel bolts, can use no. 20 alloy bolts.
