ASTM A790 covers seamless and straight-seam welded duplex stainless steel pipe for general corrosive service, with particular emphasis on resistance to stress corrosion cracking. The duplex stainless steel pipe shall be made by the seamless or an automatic welding process, with no addition of filler metal in the welding operation. Heat analysis shall be made to determine the percentages of the elements specified. Tension tests, hardening tests, flattening tests, hydrostatic test and nondestructive electric tests shall be made to conform to the specified requirements.
This abstract is a brief summary of the referenced standard. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. This specification covers seamless and straight-seam welded ferritic/austenitic stainless steel pipe intended for general corrosive service, with particular emphasis on resistance to stress corrosion cracking. These steel are susceptible to embrittlement if used for prolonged periods at elevated temperatures.
Optional supplementary requirements are provided for welded ferritic/austenitic stainless steel pipe when a greater degree of testing is desired. These supplementary requirements call for additional tests to be made and, when desired, one or more of these may be specified in the order.
Appendix X1 of this specification lists the dimensions of welded and seamless stainless steel pipe complies with all other requirements of this specification.
The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the specification. The inch-pound units shall apply unless the M designation of this specification is specified in the order.
The dimensionless designator NPS (nominal duplex stainless steel pipe size) has been substituted in this standard for such traditional terms as nominal diameter, size, and nominal size.
Source: Zhejiang Yaang Pipe Industry Co., Limited (www.yaang.com)