Stainless Steel Corrosion Vs Ph

The effect of ph on the corrosion behavior of 316l stainless steel ss was investigated.

Stainless steel corrosion vs ph.

Coatings steels passive film on stainless steel. Ph for ss316 is very complex. Oxy hydroxides of fe and cr 2 3 nm thick 0 002 0 003 µm transparent adherent self repairing mild steel coat. 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. When you compare stainless steel 17 4 ph vs 316 it is obvious that 17 4 ph has higher hardening content. 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. Zf for example a test indicates a corrosion rate of ool mils penetration per year for steel a and 002 for steel b it should not be concluded that steel a is twice as good as steel b but rather thati.

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. 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. The results are compared to these for conventional austenitic chromium nickel stainless steel cr18ni9 aisi 304 ss. Have an insight or suggestion.

Login or register to post a comment. Crevice corrosion this corrosion occurs when a crevice between the stainless steel and another material. Other considerations include ph chloride concentration and temperature of the environment in which the steel is used. 17 4 ph vs 316 offer high corrosion resistance.

Corrosion resistance of stainless passive layer vs. Others factors are also influenced on ph. Both the grades i e. Precipitation hardening grade is a combination of two stainless steel structures i e.

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.