Degradation of mechanical properties of gas steels by electrolytic saturation with hydrogen

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F47718684%3A_____%2F25%3A10002944" target="_blank" >RIV/47718684:_____/25:10002944 - isvavai.cz</a>

Result on the web

—

DOI - Digital Object Identifier

—

Result language

angličtina

Original language name

Degradation of mechanical properties of gas steels by electrolytic saturation with hydrogen

Original language description

In book of abstracts at Hydrogen Days 2025 conference. In recent years, the decarbonisation of the energy sector has become a key issue at a global level. One of the main objectives is to reduce greenhouse gas emissions. Although natural gas has a lower carbon footprint than coal or oil, it is still a fossil fuel. In this context, the focus is on replacing natural gas with greener alternatives such as natural gas-hydrogen mixtures or pure hydrogen. Hydrogen is considered the fuel of the future due to its zero-carbon content when burned. One way of gradually introducing it into the energy system is by mixing hydrogen with natural gas in blends. Such blends can be used in existing applications without significant modifications if the hydrogen content does not exceed certain limits, usually between 5-20%. This method allows a gradual reduction in greenhouse gas emissions without the need to immediately build an entirely new infrastructure.However, the main challenge is the compatibility of existing pipelines and equipment with hydrogen. Hydrogen is an extremely small molecular gas, which increases the risk of leaks. Furthermore, hydrogen can cause &apos;hydrogen embrittlement&apos; in steels, a process that degrades the mechanical properties of the material. These factors affect the safety and reliability of pipelines when transporting hydrogen-containing mixtures. Existing natural gas pipelines are mostly made of API 5L or similar gas steels. Due to the long history of gas pipeline use, steels with very different mechanical properties have been used for its construction. These include, for example, API 5 L steels X42, X46, and X52, which operate at pressures up to 13 MPa. For higher hydrogen pressures, API 5 L X60, X70 and X80 steels are used [1]. Materials developed more recently generally have higher strength and can be processed by modern processes such as thermomechanical processing, accelerated cooling and direct quenching. There is an increased density of dislocations in these materials that can promote hydrogen-enhanced decohesion and hydrogen-enhanced localized plasticity, respectively [2,3].API 5L steels X52, X60 and X70, which have different yield and ultimate strengths, were used for the experiment. These were pipes already used for natural gas. The initial structures ranged from pure ferritic-pearlitic to bainitic, depending on the steel type. The notch toughness was 77 J for X52 steel, 118 J for X60 steel and 109 J for X70 steel. Electrolytic saturation of the samples with hydrogen was carried out in a solution of 0.5N H2SO4 + 5 g/l CH4N2S and carried out for up to 48 h. The results show a significant decrease in notch toughness of up to about 22 %, depending on the steel type. The experiment was also complemented by fractographic analysis of the fracture surfaces.

Czech name

—

Czech description

—

Type

O - Miscellaneous

CEP classification

—

OECD FORD branch

20501 - Materials engineering

Project

<a href="/en/project/TH83020002" target="_blank" >TH83020002: Identification of the effect of hydrogen as a function of structural condition in pipeline distribution infrastructure and storage tanks</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2025

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů