Inconel 625 , Nickel Alloy Seamless U Tube ASTM B444 UNS NO8825 For
Heat Exchanger
ASTM B444 specifies the requirements for nickel-alloy seamless
pipes and tubes, with UNS N08825 (commonly known as Incoloy 825)
being a high-performance material designed for aggressive
environments. This alloy combines excellent corrosion resistance
with mechanical strength, making it suitable for demanding
industrial applications.
Inconel 625 Seamless U Tube Composition:
Nickel (Ni): 38-46% (provides corrosion resistance).
Chromium (Cr): 19.5-23.5% (enhances oxidation resistance).
Iron (Fe): Remainder (base metal).
Molybdenum (Mo): 2.5-3.5% (resists pitting/crevice corrosion).
Copper (Cu): 1.5-3.0% (improves resistance to sulfuric acid).
Titanium (Ti): 0.6-1.2% (stabilizes against sensitization during
welding).
Carbon (C): ≤0.05% (minimizes carbide precipitation).
Other elements (Mn, Si, S) are controlled to low levels for optimal
performance.
Inconel 625 Seamless U Tube Manufacturing:
Produced via extrusion or rotary piercing, seamless tubes ensure
superior pressure integrity and uniformity, ideal for high-stress
applications. The process avoids weld seams, enhancing reliability
in corrosive or high-pressure environments.
Inconel 625 Seamless U Tube Key Properties:
Tensile Strength: ≥586 MPa.
Yield Strength: ≥241 MPa.
Elongation: ≥30% (ensures ductility).
Heat Treatment: Solution annealed at 925-1025°C followed by rapid
cooling to optimize microstructure.
Corrosion Resistance: Excels in both oxidizing (e.g., nitric acid)
and reducing (e.g., sulfuric, phosphoric acids) environments.
Resists stress-corrosion cracking, chloride-induced pitting, and
marine atmospheres.
Inconel 625 Seamless U Tube Applications:
- Sulfuric acid production: Used in acid concentrators, piping, and
heat exchangers (resists corrosion up to 40% concentration at
elevated temperatures).
- Phosphoric acid evaporators: Handles hot, highly corrosive slurries
during fertilizer production.
- Chlorinated solvents production: Reactors and condensers exposed to
chlorine, chlorides, and organic acids.
- Subsea pipelines: Flowlines and umbilicals for seawater injection
or corrosive hydrocarbon transport.
- Refinery heat exchangers: Tubes for crude oil preheaters and sulfur
recovery units (resists sulfidation).
- Seawater cooling systems: Condenser and heat exchanger tubes in
desalination plants, ships, and offshore platforms.
Inconel 625 Seamless U Tube Standards Compliance:
Meets ASTM B444 for chemical, mechanical, and dimensional
requirements.
Compatible with ASME SB444 for pressure vessel use.
Non-destructive testing (NDT) and hydrostatic testing ensure
quality.
Inconel 625 Seamless U Tube Advantages:
Superior performance in extreme temperatures (up to 540°C).
Seamless construction enhances safety in high-pressure systems.
Versatile in multiphase corrosive environments.
