Search Results 1-20 of 1172

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Rapid Evaluation of Hydrogen Embrittlement Resistance for Spot-Welds of High Tensile Strength Steel Sheet by Slow Rate Tensile Shear Test under Hydrogen Charging Conditions [in Japanese]

Kitahara Gaku , Matsuoka Hideaki , Asada Takashi

… Automobile manufacturers are accelerating adoption of spot welding of Advanced High-Strength-Steels (AHSS) sheets to reduce weight of automobile bodies. … Rapid evaluation of the hydrogen embrittlement (HE) resistance for the spot-welds of AHSS sheets is required, since it is worried that the HE resistance of the nugget will deteriorate compared to the base metal due to the difference in microstructure caused by rapid cooling and solidification during spot welding. …

Journal of the Japan Institute of Metals and Materials 85(2), 75-83, 2021

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2

Modelling of Hydrogen Diffusion in a Weld Cold Cracking Test: Part 2, Numerical Calculations

Kasuya Tadashi , Yokobori A. Toshimitsu , Ozeki Go , Ohmi Toshihito , Enoki Manabu

… The purpose of this work is to compare the numerical calculation results of the hydrogen diffusion with the experimental results. … We firstly conducted a y groove weld cracking test using 980 MPa grade steel and 780 MPa grade welding consumable to observe HAZ cracking. …

ISIJ International, 2021

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3

Effective hydrogen diffusion coefficient of a laser weld Hydrogen release behavior from laser welds -4 [in Japanese]

MIYAZAKI Yasunobu , TATSUMI Yujiro , YASUYAMA Masanori

解析解よりレーザ溶接部水素濃度の対数は時間の1次関数となる。しかし実験的に決定した水素濃度の対数はより高次の振る舞いをすると考えられた。これは本取り扱いで拡散係数が水素濃度に依存すると考えるべきことを示している。そこで水素濃度ごとの拡散係数を決定し，さらにアレニウスプロットにより拡散係数の温度依存性を決定した。初期水素濃度から逐次計算によって，水素濃度の時間変化を推定することに成功した。

Preprints of the National Meeting of JWS 2020f(0), 256-257, 2020

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4

Time dependence of residual hydrogen concentration in laser welds Hydrogen release behavior from laser welds -3 [in Japanese]

MIYAZAKI Yasunobu , TATSUMI Yujiro , YASUYAMA Masanori

レーザ溶接により溶解した水素が，時間経過とともに減少していく過程を回帰した。溶接直後で水素濃度が高い領域では回帰関数として拡散方程式の解析解を使うことができず，現象論的により高次関数を導入することで回帰を行った。

Preprints of the National Meeting of JWS 2020f(0), 254-255, 2020

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5

Investigation of TIG Electrode Consumption Mechanism by Metal Vapor Transport from a Base Metal [in Japanese]

TANAKA Keigo , SHIGETA Masaya , TANAKA Manabu

ティグ溶接中における電極消耗メカニズムの解明を目的とし，溶接直後の電極断面に対する元素分析を実施した．溶融池表面から発生する金属蒸気がタングステン電極表面まで輸送されるとき，堆積した金属蒸気のタングステン電極に対する拡散によって電極の融点が動作温度以下にまで低下しうるため，電極消耗が促進されることが明らかになった．

Preprints of the National Meeting of JWS 2020f(0), 2-3, 2020

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6

Study on Evaluation Method for Hydrogen Embrittlement Fracture of 1500 MPa Class Ultra-High Strength Steel for Automobiles [in Japanese]

KURIMOTO Arata , SHIMIZU Kazuma , SHOJI Hiroto , OHATA Mitsuru , MORIHARA Ryuji

本研究では，1500 MPa級超高強度鋼部材の水素脆化割れ限界を， U曲げボルト締め試験にて適切に評価する手法を構築することを目的とする．そこで，U曲げボルト締め試験を実施して水素割れ発生に至るまでの時間と割れ位置を正確に計測・観察した．さらにU曲げ頭頂部近傍の応力・塑性ひずみ量・拡散性水素量の三次元分布を有限要素法により解析し，水素割れ挙動に及ぼす各局所量の影響について考察した．

Preprints of the National Meeting of JWS 2020f(0), 200-201, 2020

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7

Joint Strength Improvement in Dissimilar Friction Welding of Titanium Alloy to Nickel Alloy with Interlayer

OGURA Tomo , IMAI Tomoya , SAIDA Kazuyoshi

… The underlying mechanism of this strength improvement stemmed from a combination of interlayer brazing and solute diffusion from the base metal to the interlayer. …

QUARTERLY JOURNAL OF THE JAPAN WELDING SOCIETY 38(2), 79s-83s, 2020

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8

Simulation of diffusion controlled phenomena at the interface of steel/nickel diffusion couples [in Japanese]

SEKI Akira , OGAWA Kazuhiro

… Diffusion controlled transformation simulations of carbon steel/nickel diffusion couple were performed and the results were compared with the experimental results previously reported, which show that the interdiffusion of Fe and Ni atoms occur and the hard layer forms around the bonding interface at two step heating. …

QUARTERLY JOURNAL OF THE JAPAN WELDING SOCIETY 38(4), 269-274, 2020

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9

Influence of tool shape on formation behavior of intermetallic compounds during dissimilar friction stir welding of steel and aluminum alloy [in Japanese]

Tanaka Tsutomu , Nezu Masayuki , Uchida Sohei , Hirata Tomotake

… The effect of the welding tool shape in dissimilar friction stir welding of steel and aluminum on the formation mechanism of the intermetallic compound was investigated. …

Journal of Japan Institute of Light Metals 70(11), 503-509, 2020

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10

Amorphization at the welded boundary between 5052 aluminum alloy and zirconium by friction stir diffusion bonding [in Japanese]

Yamamoto Tokujiro , Kodama Takashi , Takayama Yoshimasa , Watanabe Hideo

… Microstructure at the boundary between 5052Al and zirconium foils subjected to friction stir diffusion bonding (FSDB) was examined by transmission electron microscopy (TEM). … The welding strength of the specimens was higher than the fracture strength of the 5052Al foil. … An amorphous phase at a welded boundary has been also reported for other dissimilar metal welding, e.g. aluminum and iron alloys, which exhibits high welding strength. …

Journal of Japan Institute of Light Metals 70(11), 523-529, 2020

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11

A Novel Joint of 18-8 Stainless Steel and Aluminum by Partial Welding Process to Ni-Plated Carbon Fiber Junction

Tomizawa Masataka , Faudree Michael C. , Kitahara Daisuke , Takase Sagiri , Matsumura Yoshihito , Jimbo Itaru , Salvia Michelle , Nishi Yoshitake

… This was done by a partial welding process of the CF junction to 18-8 stainless steel and Al separately taking advantage of the different welding temperatures of 660°C for Al, and about 1400 to 1450°C for 18-8 stainless steel. … First, the 18-8 side is fabricated by inserting half the CF junction length (10 mm) into a cut slit in 18-8 rod half length, followed by the welding and rapid solidification. …

MATERIALS TRANSACTIONS 61(12), 2292-2301, 2020

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12

Numerical Simulation on Effect of Microstructure on Hydrogen-induced Cracking Behavior in Duplex Stainless Steel Weld Metal

Ogita Gen , Matsumoto Koki , Mochizuki Masahito , Mikami Yoshiki , Ito Kazuhiro

… In addition, the microstructure of the base metal and weld metal clearly differs, affecting hydrogen diffusion and accumulation, and hydrogen-induced cracking behavior at the microstructural scale. …

ISIJ International, 2020

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13

Evaluation of Hydrogen-induced Cracking Behavior in Duplex Stainless Steel by Numerical Simulation of Stress and Diffusible Hydrogen Distribution at the Microstructural Scale

Ogita Gen , Matsumoto Koki , Mochizuki Masahito , Mikami Yoshiki , Ito Kazuhiro

… The strength level and hydrogen diffusion constant of the phases are different; … The microscopic distribution of hydrogen concentration was calculated by incorporating the stress distribution into the hydrogen diffusion simulation as one of the driving forces. …

ISIJ International, 2020

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14

Fabrication of In-situ Formed Al3Zr Reinforced Al Sintered Composites and Their Tribological Behavior [in Japanese]

NISHIMURA Nodoka , UMEDA Junko , FUJII Hiroko , JIA Lei , KONDOH Katsuyoshi

… The diffusion behavior of Al and zirconium (Zr) elements in Al matrix were studied. … particle due to a faster diffusion rate of Al compared to Zr element. …

Journal of the Japan Society of Powder and Powder Metallurgy 67(10), 536-542, 2020

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15

Estimation of hydrogen remaining in laser welds by two-dimensional difference calculation:-Hydrogen release behavior from laser welds -1 [in Japanese]

MIYAZAKI Yasunobu , TATSUMI Yujiro , YASUYAMA Masanori

レーザ溶接部には、溶接時に水素が溶解することが知られている。この水素は溶接後の冷却中にも拡散放出されることが予想される。そこで2次元差分計算を行い、室温まで冷却後にどの程度の水素が残存しているのかを推定した。その結果、溶接において溶解した水素の約半分が室温なった時点でも残存していると推定された。

Preprints of the National Meeting of JWS 2020s(0), 88-89, 2020

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16

Comparison of hydrogen release behavior from laser weld between one-dimensional diffusion and two-dimensional diffusion:-Hydrogen release behavior from laser welds -2 [in Japanese]

MIYAZAKI Yasunobu , TATSUMI Yujiro , YASUYAMA Masanori

レーザ溶接部に残存する水素量の時間依存性を1次元差分計算と2次元差分計算で比較した。また温度に依存しない１次元拡散方程式と２次元拡散方程式の解析解より得られる水素濃度の時間依存性についても比較した。その結果水素平均濃度に関しては、１次元拡散と２次元拡散で全く同じ挙動をすることが明らかとなった。またレーザ溶接部からの水素放出を取り扱うための解析解が得られた。

Preprints of the National Meeting of JWS 2020s(0), 90-91, 2020

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17

Hot Cracking Susceptibility and Solidification Segregation Analysis by Computer Simulation in Duplex Stainless Steels [in Japanese]

KIM Dong Cho , OGURA Tomo , TANABE Yoshihiro , YAMASHITA Shotaro , SAIDA Kazuyoshi

… Solidification cracking susceptibility in arc & laser welding of DSSs (duplex stainless steels) was quantitatively evaluated and the numerical simulation of solidification cracking susceptibility has clarified the affecting factors. … This is because the equilibrium partition coefficient and the diffusion coefficient of the standard DSS are larger than that of Type 310S. …

QUARTERLY JOURNAL OF THE JAPAN WELDING SOCIETY 38(2), 76-84, 2020

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18

Time-resolved and In-situ Observation of δ–γ Transformation during Unidirectional Solidification in Fe–C Alloys

Nishimura Tomohiro , Morishita Kohei , Yoshiya Masato , Nagira Tomoya , Yasuda Hideyuki

… interface confirmed that a transition from the diffusion-controlled γ …

ISIJ International 60(5), 930-938, 2020

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19

Evaluation of Hydrogen-induced Cracking Behavior in Duplex Stainless Steel by Numerical Simulation of Stress and Diffusible Hydrogen Distribution at the Microstructural Scale [in Japanese]

Ogita Gen , Matsumoto Koki , Mochizuki Masahito , Mikami Yoshiki , Ito Kazuhiro

… The strength level and hydrogen diffusion constant of the phases are different; … Incorporating the stress distribution into hydrogen diffusion simulation as one of driving forces, the microscopic distribution of hydrogen concentration was calculated. …

Tetsu-to-Hagane 106(4), 214-223, 2020

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20

Numerical Simulation on Effect of Microstructure on Hydrogen-induced Cracking Behavior in Duplex Stainless Steel Weld Metal [in Japanese]

Ogita Gen , Matsumoto Koki , Mochizuki Masahito , Mikami Yoshiki , Ito Kazuhiro

… therefore, it affects the hydrogen diffusion and accumulation, and hydrogen-induced cracking behavior at the microstructural scale. …

Tetsu-to-Hagane 106(4), 224-234, 2020

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