• TECH TALK •
Engineers( ASME), ISO, and the National Association of Corrosion Engineers( NACE). Heat affected zone hardness surveys for weld procedure qualifications need to be in accordance with NACE. Weld repairs must be applicable to ASME and ASTM standards. Through-wall repairs on any castings are not permitted without prior written approval from the end user.
Post Weld Heat Treatment( PWHT) stipulations will be based on specific material as well as applied to weld repairs and nickel butter passes using the specified heat treatment temperatures. Post Weld Heat Treatment is not necessary for C276. Qualified welding procedures to NACE for a nickel butter pass may not be applicable to PWHT.
Materials to the American Society for Testing and Materials( ASTM) standards for cast and forged bodies, bonnets, and covers are low RE carbon steel, Alloy 400 and C276.
Radiographic Testing( RT) of carbon steel body and bonnets( cover) shall be modified to critical areas. For Alloy 400 and C276 components, 100 % volume RT is required and must be approved to Level III standards. Positive Material Identification( PMI) using XRF or OES needs to be conducted according to the applicable API standards.
Testing first with helium is recommended. During the comparative testing, it was found that testing water first blocks or plugs a small throughwall leak from being detected. In the event of water being used for initial testing, the valve needs to be dried to the temperature and minimum length of time requirements.
Helium Mass Spectrometry – Accumulation Method is Preferred The accumulation method is the recommended approach for helium mass spectrometry leak testing. Other methods may be used but they must involve a bubble test and a helium detector probe. Comparative testing revealed these two methods are less effective when used individually. When combined, they can reliably detect small leaks.
Marking and Tagging Marking and tagging a tag is necessary with specific details. Preparation for shipping must entail an acid-indicating painting to the figures of the areas that must be coated on valves.
Following the publication of the MSS SP-160 Standards, an erratum was published that added a sub paragraph specifically for plug valves to be“ Certified Low-Leaking Valves.” A manufacturer shall provide a written guarantee that the valve will not leak above 100ppm for five years.
The MSS SP-160 is recommended for inclusion in future editions of industry design standards publications. •
* Author ' s Note: These are generalized excerpts from the overall MSS SP-160 document. There are too many additional requirements to provide details adequately without the actual MSS SP-160 report.
• ABOUT THE EXPERT •
According to the standards, any foundry changes must go through a new casting simulation, and partial furnace changes are not permitted.
Paul’ s career began more than 40 years ago as a Valve Design Engineer. He has participated in various industry standards committees and is an active voting member of API, ASME, MSS, and the MSS Board of Directors. He joined Bonney Forge in 2009 as Vice President of Product Engineering and is responsible for Specialties and China Operations, working closely with both domestic and international operations and sales.
16 Valve World Americas | October 2025 | www. valve-world-americas. com