A case study of a cooling pipe for a pre-cooler used in a 70-MPa hydrogen station

Saburo Okazaki, Shigeru Hamada, Hisatake Itoga, Hisao Matsunaga, Masami Nakamura, Saburo Matsuoka

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

A case study was conducted on the cooling pipe of a pre-cooler which had been used in a 70-MPa hydrogen station demonstration project. The cooling pipe consisted of a main pipe, a mechanical joint pipe and a mechanical joint. The main and mechanical joint pipes had been joined using TIG welding. Through chemical composition analysis, microstructure observation and Vickers hardness measurement, it was revealed that the main and mechanical joint pipes had been manufactured from SUS316L and that 316L was the filler metal used for TIG welding. Round-bar specimens were machined out of the main pipe in order to investigate the tensile properties of the base metal. On the other hand, both round-bar specimen without reinforcement and square-bar specimens with reinforcement were fabricated from the weld-joint. Using the three types of specimens, slow strain rate tensile tests were performed in 0.1 MPa nitrogen gas and in 115 MPa hydrogen gas at a temperature of -40 °C. Reduction of area (RA), φ, for the round base-metal specimen, the round weld-joint specimen and the square weldjoint specimen were respectively, 83.5 %, 71.3 % and 81.4 % in nitrogen gas, whereas the related values in hydrogen gas were 60.1 %, 61.3 % and 40.1 %. In other words, the RA for the three types of specimens was smaller in hydrogen gas than in nitrogen gas. Dimples were formed on the fracture surfaces of the three specimen types in nitrogen gas, whereas both dimples and quasi-cleavages were formed in hydrogen gas.

Original languageEnglish
Title of host publicationMaterials and Fabrication
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Electronic)9780791858004
DOIs
Publication statusPublished - 2017
EventASME 2017 Pressure Vessels and Piping Conference, PVP 2017 - Waikoloa, United States
Duration: Jul 16 2017Jul 20 2017

Publication series

NameAmerican Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP
Volume6B-2017
ISSN (Print)0277-027X

Other

OtherASME 2017 Pressure Vessels and Piping Conference, PVP 2017
Country/TerritoryUnited States
CityWaikoloa
Period7/16/177/20/17

All Science Journal Classification (ASJC) codes

  • Mechanical Engineering

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