API 7-1

The API 5B specification covers marking requirements and dimensions utilized by API Master thread gauges. The 5B specification is used when measuring pipe, tubing and casing threads, and each adheres to a specific set of guidelines. Various additional thread gauges and featured product threads are required when the API 5B specification is used. The following adhere to API 5B specifications:

  • Line pipe thread inspection
  • Buttress casing
  • Round thread casing
  • Extreme-line casing

API 5B Applications

API 5B specifications are applicable when API standards govern a product. Similarly, API 5B inspection procedures are used on threads featuring 11.5, or less, turns per inch. API 5B inspection procedures utilize the following measurements:

  • Taper
  • Lead
  • Height
  • Angle

Each thread dimension is measured and shown without included tolerances are considered connection design bases, and they’re not related, nor subjected to, measurements utilized to determine a product’s acceptance or rejection. Each manufacturer and purchaser is required to agree upon supplemental requirements before using API 5B specifications.

API 5B Inspection

API 5B specification thread inspection is used prior to shipment events. Manufacturers frequently measure a thread’s various intermediate points, and they inspect each again during destination delivery. Additionally, inspectors representing both the manufacturer and purchaser are required to inspect each 5B specification.

Manufacturers may utilize different methods and instruments to control manufacturing operations, and they may become flexible where specification application is required. However, acceptance or rejection of a product is entirely governed by an inspection’s results. This rule is often featured in accordance with a provided 5B specification listing, and is held in high regards during every inspection. Each API 5B specification requires consultation before implementation, and requirements must be provided by the manufacturer.