A theory is developed for the evolution of bainite as a function time, temperature, chemical composition and austenite grain size. The model takes into account details mechanism transformation, including fact that nucleation begins at surfaces, growth sheaf occurs by repeated small platelets. Predictions made using are shown to compare well against published isothermal continuous cooling transformation data.

Since 2017, the installation of Sheet-pipe system in Indonesia has marked a significant development. This initiative, collaboration between Ministry Agriculture and Japanese construction company, aims to improve water management rice paddies. The was specifically installed at Sukamandi Rice Research Center West Java, covering an area 3600m 2 . Seven parallel sheet-pipe lines, each 100 meters length 40 cm deep, were laid out. These lines consolidated into three drainage outlets regulated by...

Sequential transformation phenomena of α→γ→α during intercritical annealing and subsequent cooling were investigated to achieve a more advanced control mechanical properties in low-carbon cold-rolled DP steel sheet with chemical composition 0.13mass%C-1.4mass%Si-2.0mass%Mn. The was intercritically annealed at 1073 K for 0–1000 s, then air-cooled 873–1073 (quenching start temperature: Tq), followed by water-quenching. tensile strength increased an extension the time, especially low Tq,...

The design concepts and properties of three unique high strength steel sheets developed utilising nanoengineering are reviewed. first is by optimising the distribution nanoprecipitates exhibits low yielding ratio in spite being strengthened grain refinement precipitation hardening. second ferrite single phase tensile 780 MPa grade advanced sheet thermally stable nanosized precipitates, which possesses significantly well balanced elongation stretch flangeability. These two were already...

Industrial low alloy TRIP sheet steels contain blocky and lath-shaped retained austenite. In the present study, transformation behaviour of austenite during straining was investigated to clarify its effect on mechanical properties. Two types containing almost same amount but different morphology were used. A steel large exhibits superior ductility, sustains high work-hardenability in a strain region. On contrast, ductility. The increased steeply maximum at region, then reduced stability has...

In order to achieve high joint strength in resistance spot welding of ultrahigh-strength steel, the effect adding a 'pulsed current pattern' consisting combination short cool time and short-time high-current post-heating was investigated. Finite element analysis (FEA) for patterns experimental evaluation were conducted using 980 N mm−2 grade steel sheets. FEA shows that leads rapid heating nugget heat-affected zone (HAZ) compared conventional temper pattern sheet interface higher than centre...

本論文は,海水に曝露したセメント処理土の劣化機構について溶出試験結果および海水浸漬試験結果をもとに考察したものである.セメント処理土のカルシウムの溶出は,海水中のマグネシウムを含む塩が間隙水のpHを低下させ,溶解度が増加することによって生じることを示した.さらに,海水に最長1年間浸漬したセメント処理土の内部性状を経時的に調べ,マグネシウムの影響によるカルシウムの溶出現象を確認し,処理土のカルシウム濃度の減少がセメンテーション物質の崩壊を招き,力学的に劣化することを推定した.

An estimation method for earthquake-induced pore water pressure and the post-earthquake settlement of soft clay was developed by focusing on its Atterberg's limits direction cyclic shearing. To clarify fundamental characteristics clays with different under multi-directional shear, normally consolidated specimens Kaolinite clay, Tokyo bay Kitakyushu were subjected to simple shear undrained condition various directions strain amplitudes, followed dissipation shear-induced pressure. The effects...

To understand the γ→α transformation and control carbon contents among phases involved is most important in design of high-strength high-ductility low steels. Using a previously-developed field emission-electron probe microanalyzer (FE-EPMA) which able to suppress hydrocarbon contamination very level, concentrations at γ/α interfaces within austenite were analyzed Fe-xC-2.0Si-yMn (x=0.15 or 0.20, y=1.5 2.0 mass%) steels isothermally transformed 750°C 800°C. The paraequilibrium (PE) model...

Subsurface drainage technology may offer a useful option in improving crop productivity by preventing water-logging poor paddy fields. The present study compared two fields with and without sheet-pipe type subsurface on land water productivities Indonesia. Sheet-pipe typed is perforated plastic sheets hole diameter of 2 mm made from high-density polyethylene. It commonly installed 30–50 cm below the soil surface placed horizontally machine called mole drainer, then will automatically be...

兵庫県南部地震によって, ポートアイランドをはじめとして臨海部の埋立地においては広範囲にわたって噴砂がみられるとともに30~50cmあるいはそれ以上の地盤沈下が生じ, ライフライン等に著しい被害をもたらした. このような著しい沈下は, 表層部の埋立て土層の液状化に伴う沈下の影響が大きいと思われるが, 臨海部の人工島は粘土層上への埋立てによって築造されていることから, この粘土層の地震後沈下について検討を行った. その結果, 粘土層内で発生した過剰間隙水圧の大きさとその消散に要する時間, さらに粘土層の沈下-時間関係について定性的傾向を知ることができた.

This paper is to investigate the effect of cyclic shear direction (or phase difference) on accumulation excess pore water pressure during and recompression after shear. Several series uni-directional multi-directional simple tests under undrained condition were carried out for normally consolidated Kaolin. From test results it shown that post-cyclic settlement increase with strain amplitude difference. The values at which most significant, decrease number cycles. change void ratio in stage...

高炉水砕スラグの港湾工事への利用事例はすでに数多く報告されており,その適用性についての検討が行われている。しかしながら,陸上工事への適用性についてはあまり検討されておらず,土工材料としての高炉水砕スラグの長期的な特性変化については明らかにされていない。本研究では,高炉水砕スラグを軽量盛土材として用いた試験盛土を築造し,自然環境下での現場で長期間にわたり計測を行い,高炉水砕スラグの物理・力学特性の変化について調べた。得られた主な結論は以下の通りである。1) 高炉水砕スラグは,施工初期から施工後8年経過した現在においても,自然土と比較して十分な軽量性を維持している。2)盛土体の強度は,内部摩擦角に変化は見られないものの,時間の経過とともに粘着力が増加し一定値に収束する。3)盛土体は長期的にみて,十分な透水性を有する。

In order to achieve high joint strength in resistance spot welding of ultra steel (UHSS), the effect adding "pulsed current pattern" consisting combination short cool time and short-time high-current post-heating was investigated. Finite element analysis (FEA) for patterns experimental evaluation were conducted using 980N/mm2 grade sheets. FEA shows that leads rapid heating nugget heat affected zone (HAZ) compared conventional temper pattern long-time low-current post-heating. particular,...

The effects of partitioning Mn and Si during intercritical annealing on transformation behavior mechanical properties low alloyed TRIP-assisted steel sheets were investigated by using 0.17%C-1.5%Si-1.7%Mn steel. During annealing, concentrated in austenite ferrite partitioning, respectively. This suppressed bainite austempering decreased the volume fraction retained its C content. could be mainly because shifted T0’ curve to lower concentration region stopped at a residual austenite. decrease...

The demand for steel / aluminum alloy dissimilar joints has increased light-weighting the automobile body. However, it is well known that joining both metals by conventional welding methods, brittle intermetallic compound (IMC) generated at interface, and significantly deteriorates joint strength. In this paper, hot-wire laser brazing process using twin-spot irradiation was proposed its conditions were optimized to achieve high speed strength on a lap-fillet of combination. twin spots circle...