Sign in Start free
Grade comparison

Grade comparisons, including the rows that do not compare

There are 29 head-to-head pages here, each built from the same two data files as the grade pages behind it. Every shared property is shown with both evidence levels, and any row where the two figures are different kinds of value, or come from different documents or product forms, is marked as such instead of being resolved into a winner.

Last verified 19 August 2026.

Same family

These are the comparisons where the numbers line up: same structure, usually the same standard and the same product form, so the difference on the page is the difference between the alloys.

Austenitic stainless steel

Ferritic stainless steel

Heat-resistant austenitic stainless steel

High-alloy austenitic stainless steel

Lean duplex stainless steel

Martensitic stainless steel

Precipitation hardening stainless steel

Super-austenitic stainless steel

Across families

These need more care. A duplex against an austenitic, or a hardenable grade against either, brings differences in test basis and product form along with the difference in alloy — and on the hardenable grades the source prints typical values rather than specified minima, so several rows are marked not comparable and stay that way.

Austenitic stainless steel

Duplex stainless steel

Precipitation hardening stainless steel

Super duplex stainless steel

Super-austenitic stainless steel

How to use these

Start from the grade index if you do not yet know which two you are choosing between, or from the selection process itself if the shortlist is not settled. Read what PREN can and cannot tell you before treating a pitting ranking as a qualification, and one alloy, two standards, three numbers before carrying any minimum from one page onto a drawing governed by a different system.

What these pages do not cover

  • Cost, availability and lead time, which decide more selections than any property here.
  • Corrosion rates in your medium at your temperature.
  • Fabrication: welding procedures, forming limits, machining.
  • Any verdict. Each page says what the documents say and stops.

Generated from data/materials/*.yaml. Regenerate rather than editing this file by hand — edits here are lost on the next build.