Pitting Resistance Equivalent Number

Formula Constants

Calculations weight molybdenum and nitrogen content far more heavily than basic chromium. Within the industry standard, a pitting resistance equivalent number above forty classifies a material as a super stainless steel. Achieving this score requires significant investments in the high purity melting process.

Design Rule

Specification sheets for marine projects set a minimum limit for this value before procurement begins. While the pitting resistance equivalent number indicates relative merit, it does not predict performance in non-chloride acidic conditions. High scores on this index allow for thinner wall designs in corrosive service.

Vendor Review

Verification of the number during an audit ensures that the supplier delivered the exact grade ordered. Errors in chemistry during the batch manufacture lower the rating and risk premature failures in the field. Documentation provides the first defense against material substitution.