Sulphide stress cracking, hydrogen-induced cracking and SOHIC explained: how each one forms, which steels are at risk, and how NACE MR0175 controls them.
SSC vs HIC vs SOHIC: The Three Sour Service Cracking Mechanisms Read More »
How the API 6A hydrostatic shell test works: test pressure at 2x or 1.5x working pressure, the 3 and 15 minute holds, and the acceptance criteria.
API 6A Hydrostatic Body Test: Test Pressures and Hold Times Explained Read More »
What API 6A PR1 and PR2 mean, what a PR2 validation test involves, and why most operators now specify PR2.
API 6A PR1 vs PR2: What the Performance Requirement Means Read More »
API 6A temperature classes K, L, N, P, R, S, T, U, V, X and Y with their °F ranges, how combined classes like P+U work, and when derating applies.
API 6A Temperature Classes K to Y: What the Letters Mean Read More »
API 6A material classes AA, BB, CC, DD, EE, FF and HH explained: body and trim materials, general vs sour service, and how to choose.
API 6A Material Classes AA to HH: How to Pick the Right One Read More »
What API 6A PSL 1, 2, 3, 3G and 4 mean, what each level adds in testing and traceability, and how operators choose one.
API 6A PSL 1 to PSL 4 Explained: Which Product Specification Level Do You Need? Read More »
A Christmas tree controls the well wherever it sits. Compare surface (API 6A) and subsea (API 17D) trees: access, valves, control, intervention, ratings and why the design work moves upstream.
Surface Tree vs Subsea Tree: What Changes When the Well Moves to the Seabed Read More »
A plain guide to oil well packers: what a packer does, its key parts, permanent vs retrievable designs, setting methods and API 11D1 validation grades.
Oil Well Packers: What They Are, How They Work and the Main Types Read More »
How an API 6A gate valve works: labelled parts diagram, open vs closed, slab gate metal-to-metal sealing, stem packing and API 6A rules. Free PDF.
API 6A Gate Valve: How It Works, Parts and Sealing Read More »
If you work on wellhead or Christmas tree equipment for more than a few months, “API 6A” stops being a document you occasionally reference and becomes the language you think in — pressure classes, material classes, PSL levels. For anyone newer to the specification, or anyone who wants a single clear reference to hand a
Introduction to API 6A: Specification for Wellhead and Christmas Tree Equipment Read More »