1.1 Purpose These recommended practices provide recommendations for general specifications and performance requirements of carbon, alloy and high strength low alloy steel tube assemblies for fluid power applications utilizing commonly available manufacturing methods and general guidelines for tube selection and application. 1.2 Field of Application These recommended practices are intended for general application and hydraulic systems on industrial equipment and commercial products. Aircraft and Aerospace applications were not considered during the preparation of this document. Since many factors influence the pressure at which a hydraulic system will or will not perform satisfactorily, these recommended practices should not be construed as guaranteed minimums. For any application, it is recommended that sufficient testing be conducted and reviewed by both the user and supplier to ensure that required performance levels are met. For use of these recommended practices and connectors in conditions outside the pressure and temperature of limits specified, the fabricator must be consulted. Both metric and inch tubing should be considered to accommodate hydraulic system design requirements. In the past, these requirements have been met predominantly with inch tubing; for new designs, metric tubing should be considered.
The user community has expressed a need for additional documented knowledge associated with the design, expected performance and procurement of metallic fluid conductors. This revision to SAE J2551 reorganizes the document into three parts, design and fabrication, general specifications and performance requirements and procurement. The following changes and additional information is intended to bring this document up to date with current industry technology and provide comprehensive application and procurement information requested by the user community. In addition, the document title has been revised to include steel tube materials that have been recently added as SAE standards.