Seamless pipes solution leader Vallourec has announced the successful completion of tests qualifying the fracture toughness resistance of a selection of steel grades in the presence of pure H2 gas. In September 2022, Vallourec announced the successful completion of tests qualifying the fracture toughness resistance of a selection of steel grades in the presence of pure H2 gas. Since then, Vallourec has expanded its range of validated materials for hydrogen service, solidifying its expertise and product portfolio to assist customers in high-pressure transport and storage of H2

Vallourec succeeded in testing higher strength steels that, for certain applications, enable thinner walls, lighter solutions, and reduced resource consumption to its customers. With the growing number of low-carbon hydrogen production and use projects, ensuring the compatibility of assets for hydrogen storage and transportation is paramount. Vallourec has investigated the fracture toughness resistance and corrosion fatigue behavior of a selection of seamless pipes for OCTG, pipeline, and pressure vessels in pressurized H2 service.

Validation tests included fracture toughness evaluations conducted using fatigue pre-cracked bolt-load specimens exposed to 100 bar hydrogen gas during 1,000 hours at room temperature. All materials presented hydrogen stress intensity factor thresholds KIH largely above 55 MPa.m1/2, compliant with the ASME B31.12 option B requirement that defines materials requirements for hydrogen service.

In addition, corrosion fatigue tests were performed on compact tensile specimens prior to pre-cracking. Fatigue crack growth rate measurements were determined from 0.01 to 30 Hz and load ratios at 0.1 or 0.9 for covering applications susceptible to present very different internal pressure variations during service life.

The first selection of standard and Vallourec proprietary grades tested in the presence of pure H2 gas back in 2022 included:

⦁ Grade X65 for line pipes including the qualification of girth welds done by Serimax

⦁ Grade VM55W (55 ksi proprietary grade) for weldable OCTG pipes

⦁ Grade K55 for seamless OCTG pipes

⦁ Grade VM80S (80 ksi proprietary grade/L80) for seamless OCTG pipes

⦁ Grade 34CrMo4 for pressure vessels

Vallourec has now added the following grades to its validated material portfolio:

Grade X80 for line pipes

⦁ Grade VM80W (80 ksi proprietary grade) for weldable OCTG pipes

⦁ Grade VM95SS (95 ksi proprietary grade) for seamless OCTG pipes

⦁ Grade VM110SS (110 ksi proprietary grade) for seamless OCTG pipes

As hydrogen projects gain traction around the world, the ability to safely transport and store hydrogen gas is essential to its development and Vallourec is learning as much as possible about its grades’ behavior to hydrogen to anticipate customers’ future needs and contribute to the industry's success by providing safe and effective solutions.

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