Stainless Steel Corrosion Vs Ph

Oxy hydroxides of fe and cr 2 3 nm thick 0 002 0 003 µm transparent adherent self repairing mild steel coat.

Stainless steel corrosion vs ph.

Others factors are also influenced on ph. The results are compared to these for conventional austenitic chromium nickel stainless steel cr18ni9 aisi 304 ss. Precipitation hardening grade is a combination of two stainless steel structures i e. Both the grades i e.

Without knowing further details a general statement can be made that the lower the ph is from neutral the worse the corrosion whereas ph in the basic range is apt not to be an issue. Coatings steels passive film on stainless steel. Ph for ss316 is very complex. In the case of crevice corrosion of stainless steel the depassivation ph is the ph at which the anodic dissolution rate rapidly increases and depends on the alloying element.

The film resistance decreases and the corrosion current density increases as the ph rises from 6 42 to 7 52 for 316l ss. The corrosion rate of 316l ss increases with increasing ph in hydrogenated high temperature water at 300 c. Have an insight or suggestion. The phd is an index demonstrating the resistance of the passive film to breakdown and the most important alloying elements determining the phd are cr and mo.

Nitrogen stainless steel cr23n1 2 against general and pitting corrosion in chloride environments with ph 1 12. So it is not possible to give a ph range that 316l stainless steel can handle. Login or register to post a comment. The corrosion resistance of 17 7 ph is comparable to that of type 304 stainless steel especially in the ch 900 temper and it has been used for spring applications washers eyelets fittings and fasteners.

Acidic attack on stainless steels is very complex and depends not just on the ph but what acid is present whether the acid is weak or strong the type of acid non oxidizing versus oxidizing the temperature and level of dissolved oxygen. Corrosion resistance of stainless passive layer vs. Other considerations include ph chloride concentration and temperature of the environment in which the steel is used. Crevice corrosion this corrosion occurs when a crevice between the stainless steel and another material.

When you compare stainless steel 17 4 ph vs 316 it is obvious that 17 4 ph has higher hardening content.