DLX Inconel 625 UNS N06625 High Strength NiCrMo Alloy for Hydrogen Storage Tanks

Description of Inconel 625 UNS N06625

What is Inconel 625 UNS N06625?

In the rapidly growing hydrogen economy, material selection for hydrogen storage and transportation is critical due to the risk of hydrogen embrittlement and extreme operating conditions. DLX Inconel 625 (UNS N06625) is the industry-leading solution, combining high tensile strength, excellent fatigue resistance and virtually no susceptibility to hydrogen-induced cracking even under ultra-high pressure and temperature cycling.

Compared to conventional stainless steels and even many nickel alloys, Inconel 625 exhibits superior performance in gaseous hydrogen (GH2), liquid hydrogen (LH2) and wet H2 environments, making it the preferred liner material for composite overwrapped pressure vessels (COPV) and critical components in hydrogen refueling stations, fuel cell vehicles and stationary hydrogen storage systems.

DLX Alloy supplies Inconel 625 in all forms with tight compositional control and surface finish optimized for seamless liner manufacturing, welding and long-term hydrogen compatibility.

DLX Inconel 625 is a high-performance nickel-chromium-molybdenum alloy renowned for its exceptional resistance to hydrogen embrittlement, pitting, crevice corrosion and stress corrosion cracking in pure hydrogen and hydrogen-containing environments. Specially processed by DLX Alloy for hydrogen energy applications, our Inconel 625 products deliver unmatched durability and safety for Type III and Type IV composite hydrogen storage vessels, high-pressure gaseous hydrogen tanks, hydrogen pipelines and transport trailers operating at pressures up to 700–1000 bar.

Key Features of Inconel 625 UNS N06625

• Outstanding Hydrogen Embrittlement Resistance — Virtually immune to hydrogen-induced cracking at pressures exceeding 1000 bar and temperatures from -253°C to 650°C

• Exceptional Corrosion Resistance — Resists pitting, crevice corrosion and intergranular attack in hydrogen sulfide, chloride and acidic hydrogen environments

• High Mechanical Strength — Yield strength 414–827 MPa (60–120 ksi), tensile strength >827 MPa (120 ksi), excellent fatigue life under cyclic pressure loading

• Superior Weldability & Formability — Easily fabricated into seamless tubes, sheets and complex shapes without post-weld heat treatment

• Wide Temperature Range — Maintains properties from cryogenic liquid hydrogen storage (-253°C) to high-temperature reforming processes

• Long Service Life — Proven 20+ year performance in demanding hydrogen applications with minimal degradation

• Certified Quality — Meets ASTM B444, B446, B564, B443, AMS 5599, 5666, ISO 6208 and NACE MR0175/ISO 15156 for hydrogen service

Chemical of Inconel 625 UNS N06625

Inconel bars Chemical composition%

Application Field of Inconel 625 UNS N06625 in Hydrogen Energy

• Liner material for Type III & Type IV high-pressure hydrogen storage tanks (700–1000 bar onboard vehicles and trailers)

• Hydrogen transportation pipelines and tubing systems

• Pressure vessels and accumulators in hydrogen refueling stations

• Components for liquid hydrogen (LH2) storage tanks and transport dewars

• Valves, fittings, flanges and seals in fuel cell and hydrogen compression systems

• Cryogenic hydrogen pumps and heat exchangers

• On-board hydrogen storage cylinders for fuel cell electric vehicles (FCEV)

• Stationary hydrogen storage for renewable energy buffering

Advantage of Inconel 625 UNS N06625  

About DLX

Founded in 2002, CHANGZHOU DLX ALLOY CO., LTD is a leading manufacturer specializing in the research and production of specialized alloy materials. Our factory has earned both the ISO9001 International Quality Management System Certificate and SGS Certification, affirming our commitment to high standards of quality.

We are experts in the entire alloy production process, including melting, drawing, heat treatment, finishing, and rigorous testing. Our product range includes nickel-based, copper-based, and iron-based alloys, such as super alloys, welding materials, anti-corrosion alloys, precision alloys, FeCrAl alloys, NiCr alloys, CuNi alloys, and thermocouples. These are available in various forms including wire, strip, ribbon, bar, tube, and plate.

FAQ:

Q: Why choose Inconel 625 over 316L stainless steel for hydrogen storage tanks?

A: 316L suffers severe hydrogen embrittlement above ~200 bar, while Inconel 625 remains unaffected even at 1000 bar and maintains higher strength, allowing thinner liners and lighter overall tank weight.

Q: Is DLX Inconel 625 approved for high-pressure hydrogen service?

A: Yes, fully compliant with ISO 19881, ASME Section VIII Div. 3, and certified for gaseous hydrogen storage systems (GHS) and transportable tanks.

Q: Can Inconel 625 be used for liquid hydrogen (LH2) storage?

A: Absolutely. Its excellent low-temperature toughness and resistance to hydrogen attack make it ideal for cryogenic LH2 tanks and dewars.

Q: What is the maximum operating pressure for Inconel 625 hydrogen tanks?

A: Proven performance in commercial systems up to 1000 bar; DLX material has been qualified in multiple 700–900 bar onboard vehicle tanks.

Q: Does DLX provide custom dimensions and surface finishes for tank liners?

A: Yes, we specialize in ultra-clean, low-roughness seamless tubes and sheets optimized for autofrettage and composite overwrapping.

Q: How does Inconel 625 compare to Inconel 718 for hydrogen applications?

A: Inconel 625 offers superior corrosion and hydrogen embrittlement resistance, while 718 provides higher strength after age-hardening. 625 is generally preferred for wet/corrosive hydrogen environments and as thin-wall liners.