09/03/2026
Experience you can’t manufacture.
At Hahn & Clay, our history with ASME (The American Society of Mechanical Engineers) & The National Board of Boiler and Pressure Vessel Inspectors-certified fabrication goes back generations.
Based on the current active ASME & NB stamp holders, Hahn & Clay is proud to hold some of the longest-standing certifications in the United States:
🔹 U Stamp - issued January 20, 1951 - 5th oldest active U Stamp in the U.S.
🔹 S Stamp - issued February 6, 1952 - oldest active S Stamp in the U.S.
🔹 U2 Stamp - issued February 6, 1973 - oldest active U2 Stamp in the U.S.
🔹 R Stamp - 10th R Stamp issued in the United States
These aren't just numbers on a certificate. They represent decades of pressure vessel fabrication, machining, quality systems, engineering knowledge, and hands-on experience.
Since 1908, Hahn & Clay has continued to build on that experience while investing in the people, equipment, and capabilities needed to serve today's most demanding industries.
115+ years of experience. Generations of ASME-certified fabrication.
That's experience you can't manufacture.
