Grade 91 Refining Furnace Tube OD 30mm
Seamless Grade 91 (9Cr-1Mo-V) alloy steel tube OD 30 mm for refining furnace transfer lines. Normalized and tempered for creep strength above 600°C. Fits 7304.59.20.40: alloy steel, seamless, small OD, refining furnace suitable.
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Alternative Classifications
This product could be classified differently depending on its characteristics or intended use.
If unsuitable for listed high-temp apparatus
General service alloy tubes exclude specific boiler/refining provisions.
If welded alloy steel construction
Welding process removes it from seamless Chapter 73 headings.
If for laboratory heat exchangers
Lab-scale apparatus parts classify under machinery chapters.
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Import Tips & Compliance
• Q&T heat treatment certificates mandatory; verify against P91 specs
• Mark tubes with grade, heat number, and OD per ASTM standards
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