Hastelloy type for hydrochloride acid and sodium hydroxide

[JeroenPh]

I need to specify a metal for the construction of a sample valve. The fluids are hydrochloride acid and sodium hydroxide. My guess is some hastelloy type (B or C) but what type is best resistant to both acid an akalic fluid?

Thanks for your help/tips

 

[EdStainless]

How severe is the caustic? In general Ni alloys don't like high pH, especially if the conditions are reducing.
I will try to find you some corrosion data for "C" type alloys in in caustic.

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Corrosion never sleeps, but it can be managed.

http://www.trenttube.com/Trent/tech_form.htm

 

[JeroenPh]

EdStainless,

Thanks for your quick repley. The conditions are as follows:
HCl 30% 5 barg @ 60 deg C / NaOH 22% 5 barg @ 60 deg C.

 

[Biggy]

I would probably go for a PFA/PTFE lined sample valve. We use a lot Manufacturers whe have used CRP-Flexrite, Technova, Halwachs. Can get a bit pricy but do the job. They have some good safety features most of them will design around a standard valve for unusual duties.

Good luck.

Biggy

 

[rnd2]

According to Philip A Schweitzer the following Hastelloy grades are resistant to both sodium hydroxide as well as hydrochloric acid: (Temperature degree Fahrenheit). The tabled value indicates the resistance is "good".
"Good" is defined as <20 mils/year.

HCl Dilute 20% 35% 38% 50%
Hastelloy B/B-2 180 220 200 140 80
Hastelloy C/C-276 160 150 140 140 80

NaOH 10% 15% 30% 50% 70% Conc
Hastelloy B/B-2 230 210 250 250 220 200
Hastelloy C/C-276 230 210 210 210 220 120