Toward a Hydrogen Society: Innovation, Challenges,
and Future Prospects in the Energy Transition

• Can existing designs be used as they are?
• Is fundamental improvement necessary?

One of the major concerns in strength design is hydrogen embrittlement — a phenomenon where hydrogen atoms penetrate and diffuse into metallic materials, potentially degrading their mechanical properties in various ways.

• Delayed Fracture
　 Hydrogen accumulates in the material over time, eventually causing sudden fracture even under constant external stress. This is especially common in high-strength steels.

• Decrease in tensile properties, such as elongation at break and reduction of area
　 Hydrogen exposure reduces ductility, resulting in lower elongation and area reduction — typical indicators of embrittlement.
• Reduction in fatigue life and fatigue limit
　 Repeated loading leads to failure in fewer cycles than normal, resulting in a shorter fatigue life. In some cases, the stress threshold below which fatigue failure does not occur (fatigue limit) also decreases—a factor that must be considered in design.
• Acceleration of Fatigue Crack Growth Rate
　 Hydrogen accelerates the propagation of fatigue cracks, often by concentrating at crack tips and locally facilitating embrittlement of the material.
• Decrease in Fracture Toughness
　 Hydrogen reduces a material’s ability to resist crack propagation (i.e., fracture toughness), increasing the likelihood of brittle fracture.
　

Advantages:

• Enables strength testing while exposing the material’s surface to hydrogen gas
• Uses minimal amount of hydrogen gas, ensuring safety even if hydrogen gas diffuses outside the specimen.
• Integrates with KMTL’s core testing technologies,

➡ allowing us to meet diverse testing needs at reasonable cost.

• SSRT testing is performed with a specimen hydrogen-charged using electrochemical reactions during the process.
• Optimal for evaluating hydrogen embrittlement, including delayed fracture in corrosive environments, with a wide range of parameter settings such as electrolyte composition, current value, and test speed.
• Hydrogen concentration analysis is conducted by immersing the fractured specimen in liquid nitrogen and store it without hydrogen desorption.
• Custom design and fabrication of experimental equipment are available.

In all industrial fields, there is a need to take samples from actual products or components and conduct various material tests while simulating similar environments. However, limitations on the dimensions of materials that can be taken from actual machines often result in specimens that do not meet the size recommended by general test standards. We specialize in miniature testing technology, where small samples taken from actual components are machined into specimens and subjected to a range of testing methods. This technology has been adapted for high-pressure hydrogen gas environment, resulting in our original test method described in this document. For further details, please scan the QR code to explore our miniature testing services.