Potential Demand for Refractory Metals in Hydrogen Equipment

The high-temperature steps in the hydrogen value chain are not numerous, but they are concentrated in hydrogen production and hydrogen metallurgy. Reformer tubes for hydrogen production, support structures for high-temperature electrolysis and the internals of hydrogen-based shaft furnaces all face the combined conditions of high temperature and a hydrogen atmosphere. Tungsten and molybdenum materials are often mentioned in such discussions, and most of them are still at the validation stage.

High-Temperature Components in Hydrogen Production

Steam reforming runs at relatively high temperature and pressure, and the reformer tubes sit for long periods in an oxidizing and carburizing environment, so heat-resistant alloys are normally used. Molybdenum has insufficient oxidation resistance and is not suitable for direct exposure to oxygen-containing process gas; it can be considered only under oxygen-isolated conditions, for example as a heat shield, a support or a thermal-field reflector. Treating it as a replacement for reformer tubes overstates its performance limits.

The support structures of high-temperature electrolysis operate in an environment that alternates between oxygen and hydrogen, so material selection depends more on the specific structure. If molybdenum parts are exposed to air only during shutdown and maintenance, the risk differs completely from continuous exposure, and the protective measures and inspection frequency should be adjusted accordingly.

Material Compatibility in Hydrogen Storage and Transmission

Hydrogen diffusing in metals can cause embrittlement, and the extent depends on the material, temperature, pressure and surface condition. Molybdenum and tungsten are relatively less sensitive to hydrogen-induced embrittlement, but weld joints, coating interfaces and work-hardened layers can become weak points and need experimental data to support them. For pressure-retaining components, the material assessment required by the codes cannot be omitted.

Pressure rating is a condition that cannot be avoided. Pressure-retaining components are governed by design codes, and material assessment, welding procedure and non-destructive testing all follow established procedures; if refractory metals are to enter this field, qualification must be completed first rather than trial use on equipment.

Furnace Internals in Hydrogen Metallurgy

Hydrogen-based direct reduction runs at a lower temperature than conventional ironmaking, but the atmosphere is strongly reducing, so furnace internals are more concerned with high-temperature strength, resistance to sticking and thermal shock stability. Molybdenum alloys can be used in localized high-temperature zones, provided that atmosphere isolation and structural support are properly handled to avoid contact with oxygen-containing gas. In retrofit projects, limited space often becomes a constraint earlier than temperature.

Cost structure also determines the pace of application. Molybdenum parts carry a high unit price and a large machining allowance; if the replacement interval cannot be extended significantly, the overall economics are hard to justify. Reducing the used area in the high-temperature zone and substituting only at critical locations is a route that is easier to implement.

The Validation Route from Potential Demand to Engineering Application

• Confirm the gas composition, temperature range and number of cycles;
• Run small-sample exposure tests and observe weight gain, weight loss and surface morphology;
• Assess the stability of joints and coatings in a hydrogen environment;
• Carry out component-level thermal cycling and leak-tightness tests;
• Establish failure criteria and replacement intervals rather than a single validation.

Test samples should be kept with a control from the same batch so that material changes can be distinguished from process fluctuations, and a single short-term test should not be used in place of a long-term judgment.

Material selection for hydrogen equipment still relies mainly on mature heat-resistant alloys; the opportunity for refractory metals lies in localized high-temperature, space-constrained positions or where low vapor pressure is required. Stating the applicable scope clearly helps a project move forward better than exaggerating its prospects. The behavior of high-temperature materials in reducing atmospheres is worth evaluating early in design, and company and R&D information can be found in the company profile.