Corrosion of Common Alloys in Dry Chlorine (Cl2)
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In a couple of previous issues of our Engineering Bulletins we have already shown how Chloride / Chlorine levels in aqueous environments would affect alloy selection, and how calculation of PREN (Pitting Resistance Equivalent Number) would help in selection of an appropriate alloy for pitting corrosion resistance.
This short Bulletin considers corrosion of common alloys by dry chlorine. Well, dry Chlorine (Cl2) is not corrosive to steels at ambient temperatures and is commonly shipped and handled in carbon steel equipment, with higher-alloy materials such as Monel 400 and Hastelloy C-276 used for critical parts. The main factor that influences corrosion rates of steels by dry chlorine is temperature. Stainless Steel alloys can be usable up to about 300°C (570°F).
Corrosion rates of different alloys in dry chlorine and temperature (°C) at which given rates are exceeded are presented in the table below. Keep in mind that moisture will greatly accelerate attack of any of these materials with the additional danger of SCC (Stress Corrosion Cracking) of stainless steel.
Corrosion of some common alloys in dry Chlorine (Cl2)
Penetration Rates, [inches/year] and °F at which Given Rate is Exceeded. | |||||
Alloy | 0.005″ | 0.01″ | 0.05″ | 0.10″ | 0.50″ |
Inconel 600 | 489 | 504 | 540 | 556 | 596 |
Inconel 625 | 484 | 500 | 534 | 545 | 589 |
Hastelloy C-276 | 473 | 488 | 522 | 538 | 579 |
Inconel 825 | 388 | 407 | 451 | 472 | 527 |
ss Alloy 310 | 362 | 383 | 434 | 465 | 536 |
ss Alloy 316 | 339 | 358 | 407 | 431 | 492 |
ss Alloy 309 | 354 | 390 | 406 | 448 | |
ss Alloy 304 | 341 | 375 | 393 | 434 | |
ss Alloy 321 | 341 | 375 | 393 | 434 |
Penflex does design and manufacturer Monel and Hastelloy Chlorine Transfer Hoses in complete compliance with The Chlorine Institute’s Pamphlet 6. To learn more about them, click here.
If you have any questions or comments, please contact us.
Disclaimer: The info presented here has been compiled from sources believed to be reliable. No guarantee is implied or expressly stated here and the data given is intended as a guide only.
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