Unfortunately, stainless steels of any kind are not generally recommended for use with hydrochloric acid. Duplex alloys like 2205 are sometimes used at ambient temperature, but only at concentrations of up to 4%. Some of the highly alloyed stainless steels like 654 SMO provide useful corrosion resistance at concentrations up to 10% hydrochloric acid at ambient temperature. Better choices for 5% hydrochloric acid service are alloy 59, most any of the Hastelloy C alloys, Hastelloy B-2 (if oxidizers are not present) and tantalum.