American Petroleum Institute

Recommended Practice for Preproduction Qualification for Steel Plates for Offshore Structures - Fourth Edition
 N RP 2Z

Annotation

This Recommended Practice covers requirements for Preproduction qualification, by special welding and mechanical testing, of specific steelmaking and processing procedures for the manufacture of steel of a specified chemical composition range by a specific steel producer. This is a Recommended Practice for material selection and qualification, but not for the performance of production weld joints. This Recommended Practice was developed in conjunction with, and is intended primarily for use with, API Specifications 2W and 2Y. However, it may be sued as a supplement to other material specification s (e.g., API Specification 2H) if so desired.

PURPOSE

The purpose of these recommendations is to provide the purchaser with information which can be used to minimize the amount of time and testing necessary to prepare and certify fabrication welding procedures (and to assure that the steel to be supplied is inherently suitable for welding) with particular attention to fracture toughness and resistance to cracking of the heat affected zone. It is presupposed that welding procedures suitable for the demonstrated capabilities of the steel and intended service will be separately developed.

The specific testing required shall be that described in either Section 3 or 4 or both, as specified in the purchase order.

Demonstration of conformance to the recommendations of this practice qualifies a particular mill to produce steel manufactured to the specific chemical composition range, melting practice, and processing practice for which conformance was established. The qualification is applicable to all orders for material produced under the conditions qualified.

A significant change in chemical composition or processing practice that could be detrimental to either weldability or toughness shall require either a separate full qualification (for major change) or an abbreviated re-qualification (for minor change), as described in Section 5.