ASTM B444 UNS N06625 Nickel Alloy Steel Heat Exchanger Tube Alloy 625 Seamless Tube

ASTM B444 UNS N06625 (Alloy 625) Seamless Heat Exchanger Tube is a weld‑free, nickel‑chromium‑molybdenum‑columbium tube manufactured and tested to the ASTM B444 standard. It is specifically designed for heat exchanger service, offering outstanding corrosion resistance (especially in seawater/acids), high strength, and thermal stability. The term excludes “steel” – it is a nickel superalloy, not a steel product.

The key advantages of ASTM B444 UNS N06625 (Alloy 625) seamless heat exchanger tubes, explained simply:

• Outstanding corrosion resistance – Handles seawater, acids, and chlorides without rusting or pitting.

• High strength – Stronger than stainless steel, even at high temperatures (up to ~650°C / 1200°F).

• No weld seams – Seamless construction means no weak points or weld-related corrosion.

• Resists stress cracking – Won't crack from chloride stress corrosion (a common problem with 300-series stainless steel).

• Easy to fabricate – Can be bent, rolled, expanded into tube sheets, and welded without special difficulty.

Equivalent Grade of ASTM B444 UNS N06625 Nickel Alloy Steel Heat Exchanger Tube