Vol.8 No.2 2015

Research paper−61−Synthesiology - English edition Vol.8 No.2 pp.61-69 (Sep. 2015) automotive and infrastructure industries.Due to such a background, we believe the development of an experimental equipment that allows material testing in hydrogen gas surpassing 100 MPa, the establishment of a material testing method that allows accurate evaluation of hydrogen embrittlement and accumulation of test data using such equipment, and the diffusion to and sharing of knowledge of such material test data with related industries will greatly contribute to the international standardization of the evaluation method and qualification of materials compatibility for high-pressure gaseous hydrogen equipment. In this paper, we overview the properties of metallic materials that are demanded for use in high-pressure gaseous hydrogen equipment, including the situations in Japan and overseas. Next, we discuss the material testing equipment in high-pressure gaseous hydrogen at AIST, review the material testing methods using such equipment, and describe the international comparison of the material testing methods. Then we discuss our contribution that we may make toward the international standardization of the material testing method.2 Properties demanded for the metallic materials used in high-pressure gaseous hydrogen equipment2.1 What is hydrogen embrittlement?When a metallic material is exposed to hydrogen atmosphere, 1 IntroductionThere is a plan to commercialize fuel cell vehicles (FCV) by FY 2015 with the goals of diffusion of about 2 million FCVs that use 70 MPa high-pressure gaseous hydrogen by FY 2025 and installment of about 1,000 hydrogen filling stations.[1] In June 2014, Toyota Motor Corporation showcased an FCV scheduled for commercial sales.[2] To realize these goals, the pricing of FCV and the reduced construction cost of hydrogen filling stations are important, and the “Strategic Road Map for Hydrogen and Fuel Cell” was released to achieve a hydrogen society.[3] The high-pressure hydrogen vessel is the most expensive part of the high-pressure gaseous hydrogen equipment used in 70 MPa FCV and hydrogen filling stations. With FCV, it is called the on-board container with assumed hydrogen gas pressure of 70 MPa. It is called the pressure vessel for hydrogen stations, and the hydrogen gas pressure of 82 MPa is assumed.[4] The accumulation of material database and the establishment of evaluation technology for the effect of hydrogen on materials including pipes, valves in high-pressure gaseous hydrogen condition over 100 MPa, particularly for hydrogen embrittlement of metallic materials, are important topics in achieving a safe and economic hydrogen society. Also, harmonization of the domestic and overseas standards for materials that are used for high-pressure gaseous hydrogen equipment is expected to promote the development of low-cost equipment and parts, as well as strengthen international competitiveness of - Toward contribution to international standardization-To commercialize fuel cell vehicles and hydrogen filling stations, and to achieve a reliable and economical “hydrogen society,” international accordance of the material usage standard for high pressure gaseous hydrogen equipment is regarded as an important issue. Therefore, a precise method to evaluate the effect of gaseous hydrogen on structural metallic materials is required to qualify the materials compatibility for high pressure gaseous hydrogen equipment. For this purpose, our research group developed testing equipment capable of such examinations as slow strain rate tensile tests, fracture toughness tests, and delayed fracture tests up to 120 MPa of gaseous hydrogen. We acquired operation expertise of the equipment and testing data of commercialized metallic materials. In particular, fracture testing methods of Cr-Mo standard steel in Japan and USA were compared in an international collaborative study between Sandia National Laboratories, Livermore and our research group. We concluded that estimating fracture toughness with a rising displacement is essential for testing methods in a high pressure gaseous hydrogen environment. Development of material testing equipment in high pressure gaseous hydrogen and international collaborative work of a testing method for a hydrogen societyKeywords : hydrogen embrittlement, fracture toughness, material testing, fuel cell vehicle, hydrogen filling station [Translation from Synthesiology, Vol.8, No.2, p.62-69 (2015)]Takashi Iijima1*, Takayuki Abe1 and Hisatake Itoga21. Energy Technology Research Institute, AIST Tsukuba West, 16-1 Onogawa, Tsukuba 305-8569, Japan * E-mail :, 2. Research Center for Hydrogen Industrial Use and Storage, Kyushu University 744 Motooka, Nishi-ku, Fukuoka 819-0395, JapanOriginal manuscript received August 29, 2014, Revisions received December 2, 2014, Accepted December 4, 2014


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