The chromium grades as one group
CRA — corrosion-resistant alloy — is the collective name for the chromium-bearing tubulars a buyer specifies when CO2, chlorides or both make carbon steel a corrosion calculation instead of a material. The factory's published grade list contains five chromium designations: L80-3Cr, 9Cr, 13Cr in L80 strength class, P110-13Cr (described in the source list as super 13Cr) and 28Cr. What is published about each designation is uneven, as the table below shows. 13Cr is the designation with its own six-entry catalogue family; read the dedicated 13Cr corrosion-resistant page before raising a corrosion-resistant enquiry.
The published chromium designations
| Designation | As published | What is published about it |
|---|---|---|
| L80-3Cr | Named in the published grade list | No service data published for this designation |
| 9Cr | Named in the published grade list | No service data published for this designation |
| L80-13Cr | Grade list; own six-entry catalogue family | Per the source literature: martensitic stainless for wet CO2 service, listed in API Spec 5CT, with pitting and crevice-corrosion caution in chloride environments |
| P110-13Cr | Grade list (source wording: super 13Cr) | Named in the list only; detail confirmed per enquiry |
| 28Cr | Named in the published grade list | No service data published for this designation |
Choosing between designations is a corrosion-engineering decision driven by CO2 partial pressure, temperature, chloride content and pH. The published material supports that decision unevenly: the source literature for the 13Cr series notes both its strength in wet CO2 service and the pitting and crevice-corrosion caution that the source literature attaches to L80-13Cr in chloride environments, but no equivalent service envelope is published for the other designations, and none may be inferred from the 13Cr text. State the exact designation in the enquiry, and raise any combination outside the published list in the enquiry as its own confirmation item. Sour duty is a separate question — if a design names anti-sulphur grades, they are raised and confirmed in the enquiry.
Ordering CRA tubulars
A CRA enquiry states size, exact chromium designation, strength class, thread form and quantity. State the coupling grade your design names for a chromium string on its own line, and raise any non-standard combination in the enquiry as a confirmation item. Ask for each designation to be quoted on its own specification in the written quotation, and for MOQ, packing and lead time for it to be confirmed in the quotation.
Which chromium grades are actually published?
L80-3Cr, 9Cr, 13Cr (L80-13Cr), P110-13Cr and 28Cr appear in the published grade list. The 13Cr series additionally has its own six-entry product family; other rungs are confirmed per enquiry against the stated designation.
Is 13Cr suitable for sour (H2S) wells?
13Cr's published case is wet CO2 service, with chloride cautions. Sour duty involves different grade families and hardness rules — raise the full service conditions in the enquiry rather than extrapolating from this page.
Who decides between chromium and a heavier carbon-steel wall?
The design office. Corrosion allowance and alloy selection trade off differently per well, and this page publishes no comparison data between them; ask for the designation the design names to be confirmed in the quotation.
Request a Quotation
Send your size, grade, thread and quantity. MOQ, packing and lead time are confirmed in the quotation for your exact specification — no generic promise replaces a written quote.