300-series stainless steel is the most widely used chromium-nickel austenitic stainless steel. Its fundamental properties stem from a stable face-centered cubic austenitic structure, which imparts non-magnetic behavior, excellent corrosion resistance, good plasticity and toughness, and superior formability. These characteristics make it an indispensable basic material for everything from everyday items to advanced industrial applications.

Hydrogen Energy Industry Chain: Core Material Innovation from Storage & Transport to Application

Since 2022, significant progress has been made in the development of specialty stainless steels for high-pressure and cryogenic hydrogen environments, with practical engineering applications already realized.

1. Hydrogen Storage Tank Materials: Advancing Toward Ultra-Low Temperatures and High Strength

To meet the extreme demands of liquid hydrogen storage (-253°C), conventional SUS304L and SUS316L have been widely used for the inner shells of liquid hydrogen storage tanks and transport vessels (e.g., the world's first liquid hydrogen carrier, "Suiso Frontier"). Building on this, the development of specialty grades has become a key focus:

Ultra-low temperature specialty steels: Austenitic stainless steels such as TAS31608-LH (developed by China's Taigang), as well as STH2 and HYDLIQUID™ (developed by Nippon Steel), have been optimized through compositional adjustments (e.g., tuning Cr, Ni, Mo content and adding N, Cu). These steels maintain excellent hydrogen embrittlement resistance while enhancing cryogenic toughness and strength (e.g., STH2 exhibits tensile strength 1.2 times that of SUS316L), and are specifically designed for liquid hydrogen tank manufacturing.

Economical materials for high-pressure hydrogen storage: A technological breakthrough has been achieved by partially replacing expensive nickel with Mn-N combined alloying. Low-cost austenitic stainless steels (e.g., 06Cr22Ni10Mn8N) and lean-austenitic stainless steel clad plates have been developed. These materials reduce costs by approximately 40% while maintaining mechanical properties and hydrogen embrittlement resistance (elongation loss <15% after prolonged hydrogen charging), outperforming conventional 310S steel and making them suitable for high-pressure hydrogen storage cylinders.

2. Hydrogen Transport Pipelines: Industrial Application of Specialty Hydrogen-Embrittlement-Resistant Linepipe Steel

In the field of hydrogen transport pipelines, material resistance to hydrogen embrittlement is critical. In 2022, Shougang Group achieved mass production of L360MH high-grade hydrogen transport linepipe steel. This steel was successfully applied in China’s first high-pressure long-distance hydrogen blending pipeline project (the Guyang–Baiyunebo pipeline in Inner Mongolia, designed for 6.3 MPa with 20% hydrogen blending). The steel features a low C, Mn and Nb-V-Ti co-addition design, achieving a high proportion of high-angle grain boundaries. Its hydrogen embrittlement sensitivity index (HEIδ) under high-pressure hydrogen is controlled within 10%. As of the reporting period, over 12,000 tons have been produced.

3. Fuel Cell Bipolar Plates: Emergence of High-Cost-Performance Alternative Materials

To meet the demanding requirements of PEMFC (Proton Exchange Membrane Fuel Cell) bipolar plates—high corrosion resistance, electrical conductivity, strength, and low cost—alternative materials surpassing conventional SUS316L (yield strength ~260 MPa) have been developed:

High-strength ferritic stainless steel: A high-corrosion-resistance ferritic stainless steel (Steel A) jointly developed by Northeastern University and Taigang achieves a yield strength of 450 MPa, approximately 73% higher than 316L. Its corrosion current density in simulated cathode environments is three orders of magnitude lower than that of 316L, meeting DOE 2025 standards.

Low-nickel, low-molybdenum austenitic stainless steel: Nippon Steel’s 218N austenitic stainless steel reduces Ni and Mo content while adding nitrogen for strengthening. It offers advantages in cost, crevice corrosion resistance, and formability compared to SUS316L.