API 6A / NACE MR0175 Material Class Selector

Match your well fluid to the correct API 6A material class before you request a wellhead, Christmas tree, or casing/tubing head quote. Sour (H₂S) service and corrosion-resistant wetted parts drive the class — and the price.

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Advisory only. API 6A material classes (AA–HH) and temperature classes (K/L/N/P/S/T/U/V) are set by the full service envelope; sour-service hardness for carbon and low-alloy steels is limited to roughly 22 HRC under NACE MR0175 / ISO 15156. China Welong confirms the final class, PSL and PR level against your well data at engineering review.