Welding Inspection and metallurgy


The standard API RP 577 provides guidance to the API authorized inspector on welding inspection as encountered with fabrication and repair of refinery and chemical plant equipment and piping. Common welding processes, welding procedures, welder qualifications, metallurgical effects from welding, and inspection techniques to aid the inspector in fulfilling their role implementing API 510, API 570, API 653 and API 582. The level of learning and training obtained from this document is not a replacement for the training and experience required by the American Welding Society (AWS) Certified Welding Inspector (CWI).


The inspection of welding is a critical part of a comprehensive program of quality assurance of welding. The welding inspector includes much more than only the non-destructive examination of the completed weld. Other important issues are the revision of the specifications, set design, cleaning procedures and welding procedures. The welder qualification must be performed to help ensure that the welding works correctly in the service.


This recommended practice applies to new pressure vessels in the refining of petroleum, petrochemical and chemical plants, they work in the range of 825-1100 °F (441-595°C). It is based on decades of experience in the industry, in the results of the recent experimentation and the recent tests by independent manufacturers, manufacturers and users of the pressure vessels for this service.


Licensors and the owners of the process units in which these pressure vessels are going to use you can modify and / or supplement is recommended practice with additional requirements of property.




  • The materials and the manufacturing requirements for the new of 1 ¼ Cr-½ Mo de acero 1CR-½ Mo pressure vessels and heat exchangers for high-temperature service
  • Applies to vessels that are designed, manufactured, certificates and documented, in accordance with the ASME Code Section VIII, Division 1.
  • This document can also be used as a resource to modify the time to plan the existing pressure vessels.