Stainless Steel Corrosion Resistance Calculator

This PREN calculator is used to predict the susceptibility of Corrosion-resistant alloys(CRAs) to pitting corrosion. It is calculated on the basis of the chromium(C), molybdenum(M) and nitrogen(N) content of an alloy.


Stainless Steel Corrosion Resistance(PREN) Formula:

Stainless steel is known for its corrosion resistance in many environments in which carbon and low alloy tool steels would corrode.The corrosion resistance is a result of a very thin oxide layer on the steels surface.PREN is commonly used to rank the susceptibility of stainless steel and nickel-base alloys, and is calculated as :

PREN = C + (3.3 × M) + (16 × N)


PREN - Pitting Resistance Equivalence Number

C - chromium in percentage

M - molybdenum in percentage

N - nitrogen in percentage