Original Article

Performance of a HSLA steel produced via EAF and Arvedi ESP^™ process route for the service in gaseous hydrogen

¹ Acciaieria Arvedi, Via Acquaviva 18, Cremona 26100, Italy
² Arvedi Tubi Acciaio, Via Acquaviva 3, Cremona 26100, Italy
³ RINA Consulting – Centro Sviluppo Materiali, Viale Benedetto Brin 218, Terni 05100, Italy

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Received: 29 August 2025
Accepted: 25 February 2026

Abstract

The transition toward a low-carbon energy system requires safe and efficient infrastructure for hydrogen distribution. One of the main challenges is selecting pipeline materials capable of resisting hydrogen embrittlement and sour service conditions. This study evaluates the performance of a high-strength low-alloy (HSLA) steel, grade X46M (7.11 mm thickness), for potential application in hydrogen distribution pipelines and environments containing H₂S. The material was produced via Electric Arc Furnace (EAF) and thin slab continuous casting with direct rolling (Arvedi ESP™ process), then formed into high-frequency welded (HFW) pipes and subjected to seam annealing. A comprehensive testing program, including chemical and microstructural characterization, tensile and impact tests, and specific evaluations for hydrogen embrittlement and sulfide stress cracking, was implemented in accordance with EIGA guidelines and API 5L PSL2 and ASME B31.12 standards. Hydrogen-related performances were assessed through fracture toughness tests (K_IH) in 100% hydrogen at 80 bar for 1000 h and Slow Strain Rate (SSR) tests under 100% hydrogen. Sour service resistance was verified by Hydrogen Induced Cracking (HIC) and Four-Point Bent Beam (FPBB) tests in NACE Solution A. The results confirmed that the steel under investigation exhibits a homogeneous ferrite–pearlite microstructure, hardness below 250 HV, and mechanical properties meeting API 5L PSL2 requirements. K_IH values exceeded the ASME B31.12 threshold, while SSR tests showed only moderate ductility reduction without brittle fracture. No evidence of HIC or sulfide stress cracking was observed. These findings demonstrate that steel grades produced via the non-conventional EAF + Arvedi ESP™ route can be considered suitable for hydrogen distribution and sour service applications, supporting their potential use in future hydrogen pipeline infrastructure