Unfortunately (or maybe not?), I haven’t any experience with metallic corrosion from H2
. My hydrogen peroxide arrives in plastic (PE) & I use it in plastic tanks. An intuitive choice for best corrosion resistance to an oxidizer is an SS that can be passivated in Type VI nitric acid solution of QQ-P-35C. However, these are all austenitic SS, so to meet the magnetic requirement, choose a ferritic SS that can be passivated in Type VII solution. E.g., 17+% Cr SS Types 429, 430, 434, 436, 442, 446 or XM-47 (S44625). Less expensive alternatives with lesser corrosion resistance are the 12% Cr SS ferritic Types 405, 409 and the martensitic Types 410, 414. Also, the 16%Cr martensitic Type 431. The PH alloys may be suitable, but costly. Wouldn’t use a free-machining alloy or the high-carbon 440’s.
Checked some online chemical resistance selectors for materials resistant to 30% H2
Results: plastics like PTFE, non-magnetic metals tantalum, zirconium, niobium, titanium and the high nickel alloys.
A survey of half a dozen corrosion books was similarly fruitless: non-magnetic alloys and high Ni- and Si-cast irons.
For general resistance to peroxide in neutral or alkaline solutions: austenitic SS is Normally Excellent, Ni-Resist cast iron is Good to Excellent, and mild & low alloy steel are Good – Suitable when superior alternatives are uneconomical. – Perry’s Chemical Engineers’ Handbook, 6th & 7th Edns.
Specific resistance to 30% hydrogen peroxide: steel has a corrosion rate > 0.050 inch/year at room temperature and above. 12% Cr, 17% Cr and 316 SS’s have corrosion rates in the range 0.002 to 0.020 inch/year at 225o
F for H2
concentrations to 50%. Nickel corrodes 0.002 to 0.020 inch/year for 100% H2
at room T. -- Perry’s, 6th Edn.
, pp. 23-29 to 23-30.
I would recommend the 400 series SS’s listed in the first paragraph. However, depending upon the A311 grade, the ferritic SS’s even in cold-drawn condition may not meet YS requirements. The martensitic SS’s in Q + T condition should exceed A311 mechanical requirements.
Cr plating (over duplex Ni, of course) of the existing alloy should also work, but would require good rinsing after each cleaning. [Actually, good rinsing should be required in any case.]
So, all things considered, end up in agreement with Metalguy