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Hastelloy type for hydrochloride acid and sodium hydroxide

Hastelloy type for hydrochloride acid and sodium hydroxide

Hastelloy type for hydrochloride acid and sodium hydroxide

(OP)
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

RE: Hastelloy type for hydrochloride acid and sodium hydroxide

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.

= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.
http://www.trenttube.com/Trent/tech_form.htm

RE: Hastelloy type for hydrochloride acid and sodium hydroxide

(OP)
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.

RE: Hastelloy type for hydrochloride acid and sodium hydroxide

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

RE: Hastelloy type for hydrochloride acid and sodium hydroxide

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

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