圧力技術
Online ISSN : 1347-9598
Print ISSN : 0387-0154
ISSN-L : 0387-0154
57 巻, 2 号
選択された号の論文の5件中1~5を表示しています
論文
  • 酒井 信介, 岩崎 篤, 佐々木 哲也, 宮崎 信弥, 石崎 陽一, 戒田 拓洋
    2019 年 57 巻 2 号 p. 66-72
    発行日: 2019年
    公開日: 2019/04/25
    ジャーナル フリー
    HPIS Z109 TR: 20161) which treats the procedure for evaluating the soundness of local metal loss found at the time of inspection based on reliability has been published. Although this TR summarizes the basic concept in applying reliability engineering to the metal loss evaluation, in order to widely utilize this technology, it is necessary to develop a partial safety factor table according to reliability targets for a wide range of the geometry, material, and operation condition of the pressure vessel and pipe to be applied. Therefore, working group was newly constructed in the RBM committee, and a partial safety factor table covering piping and pressure vessels in a wider range was created. In this report, we will summarize its basic principle and concept, propose a method for expressing a partial safety factor table in the standard, and present calculation results of a representative case.
  • 土田 豊
    2019 年 57 巻 2 号 p. 73-81
    発行日: 2019年
    公開日: 2019/04/25
    ジャーナル フリー
    Experimental thermal desorption curves of vanadium (V)-bearing high strength steel were successfully separated, by the use of Gaussian distribution function, into desorption curves for hydrogen traps of dislocation (A1) , grain boundary (A2) , two types of vanadium carbide (V1 and V2) . The amount of A2 hydrogen (hydrogen trapped by grain boundary) rationalized the strength in different types of hydrogen embrittlement tests, i. e. conventional strain rate test (CSRT) , slow strain rate test (SSRT) and constant load test (CLT) . The strength dropped steeply beyond the threshold amount of 0. 15 ppm. All the four kinds of trapped hydrogen (A1, A2, V1 and V2) were revealed in equilibrium of Fermi-Dirac statistics. Over half of total hydrogen was trapped by the two kinds of V-carbide (V1 and V2) , and the rest was partitioned into A1 and A2 hydrogen; more hydrogen was partitioned into A2 hydrogen by SSRT and CLT than by CSRT. The partitioning was hardly affected by vanadium alloying. The threshold amount of A2 hydrogen may be originated by the suppressed amount of impurity atoms and carbide along grain boundary.
  • -レーザピーニングの効果-
    笛木 隆太郎, 高橋 宏治, 粂野 文亮, 澁谷 紀仁
    2019 年 57 巻 2 号 p. 82-91
    発行日: 2019年
    公開日: 2019/04/25
    ジャーナル フリー
    The effects of laser peening (LP) on the bending fatigue limit of an austenitic stainless steel JIS-SUS316 welded joint containing an artificial semi-circular slit on the weld toe were investigated. The optimum LP condition which was expected to have a good effect in fatigue limit improvement was determined by measuring the residual stress distributions for several LP conditions. Then, three-point bending fatigue tests were carried out at a stress ratio of R=0.05 for both LP treated welded specimens with the slit on the weld toe and those without the slit. The fatigue limits of all specimens increased by 23-64% due to LP. LP treated specimens with a slit depth of a=0.2 mm had high fatigue limits that were nearly equal to those of non-slit, LP treated specimens. Therefore, a semi-circular slit of less than a=0. 2 mm could be rendered harmless due to LP. The improvement of fatigue limit due to LP was mainly achieved by compressive residual stress.
解説
  • 吉田 聖一
    2019 年 57 巻 2 号 p. 92-99
    発行日: 2019年
    公開日: 2019/04/25
    ジャーナル フリー
    On February 8, 2017, a foul condensate tank exploded at the Packaging Corporation of America paper mill in DeRidder, Louisiana, USA. The explosion killed three workers and injured seven workers. The non-condensate gas in the vapor space of the tank ignited by the welding fire. The explosion separated the tank from its bottom plate and launched it from its ground-level position up and over a six-story building, landing approximately 110 m away. The U. S. Chemical Safety and Hazard Investigation Board (CSB) released the final report on the cause of this incident on April 24, 2018. This paper describes the incident from the viewpoint of the explosion of the liquid storage tank based on the CSB report.
  • 伊藤 吾朗, 倉本 繁, 車田 亮, 小林 純也, 浅見 重則, 小川 武史
    2019 年 57 巻 2 号 p. 100-107
    発行日: 2019年
    公開日: 2019/04/25
    ジャーナル フリー
    The newly issued standard, HPIS E 103: 2018, “Standard Test Method for Humid Gas Stress Corrosion Cracking of Aluminium Alloys for Compressed Hydrogen Containers” has been reviewed. This standard specifies the indicated test method and the qualification criteria of aluminium alloys for compressed hydrogen containers for automotive use. It was established at the request of automotive industry in order to evaluate the HG-SCC susceptibility of aluminium alloys used in compressed hydrogen containers. In this standard, the humidity as well as the temperature of the environment where the pre-cracked test piece is maintained is explicitly specified unlike ISO 7866Annex B (Sustained-Load Cracking Test) , considering that the inside of the compressed hydrogen container may be subjected to high relative humidity at about -7°C arising from impurity water vapor (maximum 5ppm) .
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