Development of 6% nickel steel for LNG storage tanks

Hitoshi Furuya, Naoki Saitoh, Yasunori Takahashi, Katsumi Kurebayashi, Yoichi Kayamori, Takehiro Inoue, Ryuji Uemori, Motohiro Okushima

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

5 Citations (Scopus)

Abstract

9% Ni steel has been used for LNG storage tanks for more than four decades although 5.5% Ni steel (N-TUF CR196) was developed in the 1970's using a special heat treatment method named L-treatment. The reason why the actual application of 5.5% Ni steel has not been attained to LNG storage tanks is mainly because the requirement of fracture properties is not confirmed for the tanks. Under the circumstances of expanding demand for natural gas and double-integrity in LNG storage tanks, we restarted developing low Ni steel for LNG storage tanks by using both conventional and advanced techniques. For the application of low Ni steel to the present LNG storage tanks, both fracture initiation and propagation properties of base metal plates and welded joints should be concerned. The fracture initiation and propagation properties of base metal were compensated with the intercritical reheating process (L-treatment), and the propagation property was additionally enhanced by combining TMCP with L-treatment. In addition, the chemical composition adjustment and the homogenization treatment of solute elements were conducted for improving the fracture initiation and propagation properties of welded joints. 6% Ni steel plates were manufactured by the process of continuous casting, reheating, hot rolling, direct quenching (TMCP), L-treatment, and tempering, and their chemical composition was 0.05C-0.06Si-1.0Mn-6.3Ni-Cr-Mo. As the results of fracture property evaluation including large-scale fracture tests such as the duplex ESSO test and the wide plate tensile test, it was demonstrated that 6% Ni steel has good characteristics regarding brittle fracture initiation and propagation in base metal plates and welded joints.

Original languageEnglish
Title of host publicationASME 2011 30th International Conference on Ocean, Offshore and Arctic Engineering, OMAE2011
Pages327-331
Number of pages5
DOIs
Publication statusPublished - Dec 1 2011
Externally publishedYes
EventASME 2011 30th International Conference on Ocean, Offshore and Arctic Engineering, OMAE2011 - Rotterdam, Netherlands
Duration: Jun 19 2011Jun 24 2011

Publication series

NameProceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE
Volume3

Other

OtherASME 2011 30th International Conference on Ocean, Offshore and Arctic Engineering, OMAE2011
CountryNetherlands
CityRotterdam
Period6/19/116/24/11

All Science Journal Classification (ASJC) codes

  • Ocean Engineering
  • Energy Engineering and Power Technology
  • Mechanical Engineering

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