茨城大学
理工学研究科(工学野)
機械システム工学領域

助教

小林 純也

コバヤシ ジュンヤ
KOBAYASHI Junya

学位

  1. 博士(工学)

研究分野

  1. 材料加工・組織制御工学
  2. 構造・機能材料

研究キーワード

  1. アルミニウム合金,高温変形特性,引張特性,成形性,高圧水素貯蔵容器 低合金TRIP鋼,残留オーステナイト,マルテンサイト,熱処理,金属組織

研究テーマ

  1. アルミニウム合金のスピニング加工 2015/04/01-現在
  2. アルミニウム合金の高温における変形特性

論文

  1. 研究論文(国際会議プロシーディングス) 共著 Hot spinning formability of aluminum alloy tube Shunichiro Nakasato, Junya Kobayashi, Goroh Itoh Procedia Manufacturing 15, 1263-1269 2018 10.1016/j.promfg.2018.07.360
  2. 研究論文(その他学術会議資料等) 関東地域3支部新進部会若手学生研究交流会実施報告 小林 純也 塑性と加工 一般社団法人 日本塑性加工学会 58/ 674, 221-221 2017 0038-1586 URL
  3. 研究論文(国際会議プロシーディングス) 共著 Spinning workability of Al-Mg-Si alloy extruded tube using the forming die Fumiya Nanjo, Junya Kobayashi, Goroh Itoh Procedia Engineering 207, 1761-1766 2017 10.1016/j.proeng.2017.10.935
  4. 超高強度低合金TRIP鋼の組織と機械的性質 杉本公一,小林純也,北條智彦 鉄と鋼 103/ 1 2017
  5. 研究論文(学術雑誌) 共著 Warm Formability of 0.2 Pct C-1.5 Pct Si-5 Pct Mn Transformation-Induced Plasticity-Aided Steel Koh-ichi Sugimoto, Shin-nosuke Hidaka, Hikaru Tanino, Junya Kobayashi Metallurgical and Materials Transactions A 48/ 5, 2237-2246 2017/03/08 doi.org/10.1007/s11661-017-4046-5

研究発表

  1. シンポジウム・ワークショップ パネル(公募) トリチウムオートラジオグラフィによる金属材料中の水素の挙動解析 2017
  2. 口頭発表(一般) 加工後に取り出し可能な成形型を用いた口端部スピニング加工 茨城講演会講演論文集 2017 URL Spinning is a forming method which forms the flat disk metal into cylindrical metal. Spinning is also used to neck-form the tube end,such as the high-pressure hydrogen storage container.The 6061 aluminum alloy is used as a liner material of the container.The tube end of the liner is neck-formed by spinning without forming die.In this case, there is an issue that the forming defect may be introduced at the inner surface of container after neck-forming.It is considered that the defect in the forming is suppressed by spinning with forming die.However, such as a shape like a high-pressure hydrogen storage container, the mold can not be removed from the container after spinning. Therefor spinning is usually carried out without the mold. In this study, a removable mold which can be taken out after spinning applies for production of a shape like a high-pressure hydrogen storage container.
  3. 口頭発表(一般) SSRT 試験法による難燃性マグネシウム合金の水素脆化特性の評価 茨城講演会講演論文集 2017 URL Now, saving energy and effective utilization of resources are demanded from environmental problems, such as global warming and the depletion of the resources. Magnesium is expected as a promising structural material of next-generation since they are lightweight and excellent in recyclability. In recent years, flame-resistant magnesium alloys which have been developed as a candidates of the body structure in high speed railways. However, several important mechanical properties other than tensile properties, such as fatigue and resistance to hydrogen embrittlement (HE) have not been assessed in detail in these alloys so far. With respect to the HE of conventional alloys, HE has been reported to occur in an AZ31 alloy. In this study, the newly developed flame-resistant alloys, AX81 and AZX611 were subjected to slow strain rate technique tensile test in moist air and dry nitrogen gas environments to examine whether HE takes place in these alloys.
  4. フェライト系ステンレス鋼中の水素挙動 茨城講演会講演論文集 2017 URL Hydrogen embrittlement (HE) significantly reduces the ductility of metals and its mechanism has not been elucidated. Hydrogen embrittlement is caused by diffusible hydrogen but it is difficult to be observed. Tensile test was conducted on a ferritic stainless steel both with and without simultaneous cathodic hydrogen charging to examine the effect of hydrogen on the elongation to failure. About 35% of elongation to failure was obtained in the uncharged specimen with a dimpletype fracture surface. In contrast, when specimen was tested with simultaneous charging, the elongation decreased to about 8%, with a quasi-cleavage fracture surface. Thus, it was confirmed that HE takes place in this steel. In addition, a test piece was subjected to a tensile plastic deformation of 7% with simultaneous charging, aged at 25℃ for 168h, and then tensile-tested without hydrogen charging. By this treatment, the total plastic strain to failure was recovered to almost the original value, i.e., 35%. Hence, it is deduced that no undiffusible defect remains in the specimen after the tensile deformation of 7%.
  5. Al-Mg-Si 合金の耐湿潤ガス応力腐食割れ特性に及ぼす主成分の影響 茨城講演会講演論文集 2017 URL Recently, the fuel cell vehicle which uses the hydrogen energy has been attracting attention because of environmental problems such as global warming and depletion of fossil fuel. With the spread of fuel cell vehicles, lower cost of each component is required. High-pressure hydrogen container for fuel cell vehicle is composed of a liner of 6000 series aluminum alloy and shell of carbon-fiber-reinforced plastic(CFRP). Higher strength aluminum is demanded to decrease the cost of the hydrogen container by reducing the amount of the expensive CFRP. Humid gas stress corrosion cracking test is one of the ways to examine the safety of aluminum alloys. However, the effect of the main alloying elements (Mg, Si, Cu) on the humid gas stress corrosion cracking behavior is not clear. In this study, using aluminum samples of various compositions, we investigated the effect of alloying elements on the humid gas stress corrosion cracking behavior in 6000 series aluminum alloys.