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74 巻, 5 号
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松宮 徹1988 年 74 巻 5 号 p. 753-763
発行日: 1988/05/01
公開日: 2009/05/29
ジャーナル フリーPDF形式でダウンロード (1873K) -
加藤 榮一1988 年 74 巻 5 号 p. 764-775
発行日: 1988/05/01
公開日: 2009/05/29
ジャーナル フリーPDF形式でダウンロード (4895K) -
飯野 牧夫1988 年 74 巻 5 号 p. 776-785
発行日: 1988/05/01
公開日: 2009/05/29
ジャーナル フリー鉄鋼の水素誘起脆性の本質を明らかにし,かつ現実に生じている鉄鋼の水素脆化にからむ問題解決の指針を求めるために,これまでに多くの研究がなされている.第2章に述べたいくつかの水素脆化モデルないし仮説は,非常に抽象的で一見役にたちそうにないように見えるものをも含めて,これまでに人類がこの問題の解決に傾けた知性の諸表現を整理する道標としてまあまあ納得できるものばかりであることに気付く.幾多の論争を経て,現在では水素脆化進展の速さをも説明できるものとして,転位による水素の運搬また同時に水素による転位易動度の増大という相互に強め合う二つの要素が水素脆化の進展に切つても切り離せない過程であり,従つてこれらの要素がモデルの中に入つていなければならないと,考える研究者が増えている.
鉄鋼中には,転位以外にも水素と相互作用を及ぼし合ういろいろな欠陥が含まれている.問題の大きい高強度鋼は,種々の密度Nの点欠陥(固溶硬化),線欠陥(高密度転位による強化),面欠陥(結晶粒微細化による強化,析出強化)など諸欠陥の導入によつて生まれた材料である.水素はこれらのすべての欠陥といろいろな大きさの相互作用をもつ.水素が転位(HB≈0.28eV)に運ばれてこれらの諸欠陥(これらもHBの大きさに応じた量の水素をかかえている)に遭遇するとき,最低の知識として,水素がどちらの方向にもらわれていくかを知らなければ,上に述べたモデルは役に立たないものになる.ところが,このHB及びNをこの目的の議論に耐える精度で求める方法論が現在まだ確立していない.この定量的ないし解析的側面の導入部分については以上に紙面の許す限り述べた.高温加熱による水素放出ピーク温度と水素トラップ結合エネルギーの関係については別の機会に述べることとする.
近年工業的重要性を増しているオーステナイト系ステンレス鋼,また更にf.c.c.金属の水素誘起脆性についてもその概要を述べた.b.c.c.Feの場合と同様に,f.c.c.金属の場合にも,転位による水素の輸送及び水素による転位の活性化を示す実験事実がこれまでに報告されているが,その機構に関してはb.c.c.Feの場合より更に不明な点を残している.両金属中の水素拡散の活性化エネルギーの著しいコントラスト,また水素化物形成傾向の違いが両金属中の水素-転位相互作用機構の違いをもたらす因子として本質的な役割を果たしているのか否かまず明らかにする必要がある.抄録全体を表示PDF形式でダウンロード (2112K) -
重野 芳人, 洪 明在, 小林 三郎, 大森 康男1988 年 74 巻 5 号 p. 787-793
発行日: 1988/05/01
公開日: 2009/05/29
ジャーナル フリーIn order to evaluate the abrasive resistance of coke oxidized with CO2 gas, the rotational abrasive disk was used. The specimens of metallurgical and formed coke were oxidized unidirectionally with gas mixtures like bosh gases. The relation between the abrasive resistance and conversion ratio was studied. The results are summarized as follows:
1) The abrasive resistances of the bulk and matrix of coke can be evaluated distinctively by the indicies proposed in the present study.
2) The index proposed to show the abrasive resistance of the bulk coke against the abrasive wear has the linear relation with the conversion ratio.
3) The abrasive resistance of the bulk of coke decreases extensively with the increase in conversion ratio, while that of matrix does not decrease so much. Therefore, the degradation of coke can be attributed mainly to the decrease in the bulk resistance due to the enlargement of pore.抄録全体を表示PDF形式でダウンロード (1187K) -
櫻谷 和之, 古山 貞夫, 吉松 史朗1988 年 74 巻 5 号 p. 794-800
発行日: 1988/05/01
公開日: 2009/05/29
ジャーナル フリーThe behavior of gaseous reduction of molten slag containing niobium oxide was examined for the purpose of making ferro-niobium alloy of good quality.
The molten slag containing niobium oxide was reduced in the crucibles made of high purity magnesia or pure iron with H2 gas, CO gas and H2-CO gas mixtures. The results are as follows;
(1) Iron oxide and P2O5 in the slag were easily reduced with H2 gas while they were slightly reduced with CO gas at 1 450°C.
(2) The slag elements except FeO, Fe2O3 and P2O5 were scarcely reduced with H2 or CO gas in the temperature range from 1 350 to 1 550°C.
(3) The reduction of FeO with H2 gas was accelerated by the increase in MgO content in slag.
(4) The relation between (%FeO) and (%P2O5) in reduced slags is expressed in the following equation:
(%P2O5)=0.037(%FeO)+ 0.04抄録全体を表示PDF形式でダウンロード (4470K) -
藤田 正樹, 片山 裕之, 石川 英毅, 梶岡 博幸1988 年 74 巻 5 号 p. 801-808
発行日: 1988/05/01
公開日: 2009/05/29
ジャーナル フリー上底吹き転炉を用いた溶融還元法をフェロマンガン製造に応用することを目的として,70kg規模基礎実験と600kg規模上底吹き実験により,マンガン焼結鉱の溶融還元反応を調べた.
(1)(T.Mn)の挙動は,1次反応式で整理できる.反応速度定数:k1と十分な時間経過後の到達マンガン濃度:(T.Mn)fに影響をおよぼす主要な要因は,CaO/SiO2比,温度,[%Mn],コークス量,および底吹き攪拌条件である.
(2)[Mn]が25%以上では,k1と(T.Mn)fは[%Mn]に関係なくほぼ一定となる.k1が一定になるのは,還元反応がおこる場所がコークス-スラグ界面に限定されるためであることを,X線透過による直接観察で確認した.
(3)クロム合金の場合とは異なりマンガン合金では,底吹きO2が再酸化とダスト生成に悪影響をおよぼしていることが認められた.
(4)酸素の上吹き条件としては,クロム合金の場合と同様,酸素ジェットがメタル浴にあたらないように多量スラグ共存状態でソフトブローすることが重要である.
フェロクロム溶融還元製錬の原理は,操業条件の一部を変えることにより,フェロマンガン製造にも応用できる可能性があることを明らかにした.本法は,将来,各種フェロアロイの製造を集約することが必要となつた場合などに特長を発揮できると考えられる.
本研究の取りまとめにあたり,九州大学名誉教授・新日本製鉄株式会社顧問川合保治博士の御指導をいただきました.また,X線透過実験については,東京大学工学部金属工学科反応設計教室の装置を使わせていただき,相馬胤和教授,天辰正義博士の御指導を受けました.抄録全体を表示PDF形式でダウンロード (1282K) -
瀧口 新市, 佐野 信雄1988 年 74 巻 5 号 p. 809-815
発行日: 1988/05/01
公開日: 2009/05/29
ジャーナル フリーIn view that Fe-Cr-C melts should be dephosphorized preferably by CaO bearing fluxes for economical reasons, the lowest phosphorous content attainable in equilibrium by the treatment was estimated by measuring 1) the GIBBS free energy of formation of CaO·Cr2O3, which determines the maximum oxygen partial pressure and 2) phosphorous distribution between CaO-SiO2-CaF2 fluxes and Fe-Cr-C melts at 1 300°C.
The results are summarized as follows:
1) The Gibbs free energy of formation of CaO·Cr2O3 can be expressed by the following equation.
2Cr(s)+ CaO+ 3/2O2= CaO·Cr2O3
ΔG°=-1 350 000 + 344 T±10 000 J/mol
2) For effective dephosphorization of carbon saturated Fe-16%Cr melts the phosphate capacity of the flux must be higher than 1027.
3) The addition of a small amount of Na2O or BaO to CaO-SiO2-CaF2 fluxes saturated doubly with CaO and 3CaO·SiO2 was observed to increase significantly their dephosphorization capacity.
4) The interaction parameter ePCr was found to be -0.039 at 1 300°C.抄録全体を表示PDF形式でダウンロード (1176K) -
藤田 正樹, 片山 裕之, 山本 明, 松尾 充高1988 年 74 巻 5 号 p. 816-822
発行日: 1988/05/01
公開日: 2009/05/29
ジャーナル フリーマンガン合金溶湯([Mn]:5~60%)に対して,種々の塩基性酸化物の炭酸塩を含むフラックスを添加して脱りん実験を70kg規模で行つた.主な結果は次のとおりである.
(1)CaCO3系ではほとんど脱りんがおこらない.NaCO3系とLi2CO3系では脱りん率が低く,かつ復りん傾向がある.これに対してBaCO3系は比較的脱りん率が高く,復りん傾向が認められないことから,BaCO3系に絞つて実験を進めた.
(2)BaCO3系フラックスによるマンガン合金処理時には,クロム合金の場合とは異なり,BaCl2を配合せずBaCO3単味の方が得られる脱りん率は高い.これは生成したMnOがスラグ融点を低下する作用があるためである.
(3)BaCO3系フラックスによる脱りんを有利に進めるには,(i)処理温度が低いこと,(ii)[%C]は飽和値より少し低い程度であること,(iii)(%BaO)を極力高い値に保つためにSiO2などの混入を抑制することなどが望ましい.
(4)[%Mn]に応じて,雰囲気の酸素ポテンシャルの調整やフラックスインジェクションなどを行つて,生成するMnOを適正量((%MnO):20~40%)に制御することは,効率的な脱りんのために有効である.
(5)通常の高炭素フェロマンガン溶湯を,約1300℃においてBaCO3で処理すれば,(P)/[P]として15~20程度が期待できる.抄録全体を表示PDF形式でダウンロード (1111K) -
原 義明, 北岡 英就, 桜谷 敏和, 野崎 努, 西川 廣1988 年 74 巻 5 号 p. 823-830
発行日: 1988/05/01
公開日: 2009/05/29
ジャーナル フリーA study was made on the desulfurization rate of steel by CaO-CaF2 powder injected into a 150 t ladle.
EPMA analysis of suspending particles taken from an Al-Si killed steel melt during powder injection was made, and two types of particles contributing to desulfurization were found. The one formed by coalescense of injected powder with deoxidized Al2O3 particles showed a high sulfur partition ratio of 1 000 to 6 000. The other type of suspending particles formed by coalescense of injected powder with entrained top slag and Al2O3 showed a lower sulfur partition ratio. Observed sulfur partition ratios of both types of particles agree with those estimated from thermodynamic calculation, which indicates that the reaction between suspending particles and sulfur in a steel melt is in equilibrium.
A model was proposed, which took account of resulfurization from top slag. Calculation based on the model shows that the contribution of transitory reaction to overall amount of desulfurization is approximately 46% under this experimental condition.抄録全体を表示PDF形式でダウンロード (4393K) -
川上 公成1988 年 74 巻 5 号 p. 831-838
発行日: 1988/05/01
公開日: 2009/05/29
ジャーナル フリー酸素ジェット火点の温度測定結果について光輝輻射温度を定義し,火点の光輝輻射温度範囲として2000~2600℃を求めた.火点における金属の蒸発現象についてHERTZ-KNUDSEN-LANGMUIR式により解析を行い,Feの蒸発速度定数K0Feを求めた.Mnに関しては液相側攪拌律速であることから,R.G.WARDの漸近線の思想を導入しFeの沸点においてK0Fe=KMnの仮定を設けてKMnを求めた.
酸素ジェットの火点現象に関して,Counter-flux-transport現象との差異を明らかにし,Fe-O界面活性,脱炭反応との関わりについて考察した.抄録全体を表示PDF形式でダウンロード (1258K) -
吉原 直武, 福田 脩三, 上野 康1988 年 74 巻 5 号 p. 839-846
発行日: 1988/05/01
公開日: 2009/05/29
ジャーナル フリーIn the operation of continuous annealing lines for thin strips, one of the main problems is to ensure a good flatness especially during roller quenching.
This paper deals with the heat buckling of strip during roller quenching and the pinch defect, namely, folding up of the buckled portion on the roller.
The theoretical analysis on those phenomena is carried out. It allows clarification of those mechanisms, factors and countermeasures.
The pinch index is presented, quantitatively showing the influence of various factors on pinch defects. This index gives the prediction for shape defects in actual operation, and is useful for its prevention and the design of the roller quenching system in the continuous annealing line.抄録全体を表示PDF形式でダウンロード (1166K) -
菊竹 哲夫, 徳永 良邦, 中尾 仁二, 伊藤 亀太郎, 高石 昭吾1988 年 74 巻 5 号 p. 847-854
発行日: 1988/05/01
公開日: 2010/01/15
ジャーナル フリーThe effect of Al and N on the notch toughness and tensile strength of heavy section pressure vessel steel plates is investigated. Notch toughness of steel A533B (Mn-Mo-Ni), which has mixed microstructure of ferrite and bainite, is drastically changed by the ratio of sol.N/sol.Al. With metallurgical observations, it is revealed that AlN morphology is influenced by the ratio of sol.N/sol.Al through the level of solute Al (CAl). At the heat treatment of heavy section steel plate, AlN shows OSTWALD ripening and its speed depends upon CAl. When Al is added (Al≥0.010%) in steel and sol.N/sol.Al≤0.5, CAl remains low. This prevents AlN ripening, and brings fine austenite grain size and high toughness. On the other hand, when sol.N/sol.Al<0.5, CAl becomes high and this gives poor toughness through coarse AlN precipitates and coarse austenite grain. Therefore, controll of sol.N/sol.Al over 0.5 is favorable to keep high toughness in A533B steel. In steel A387-22 (Cr-Mo) which has full bainitic microstructure, too fine austenite grain brings about poor hardenability, and polygonal ferrite, which brings about both poor strength and toughness, appears in mi crostructure. Then sol.N/sol.Al<0.5 is better to give high hardenability in steel A387-22.抄録全体を表示PDF形式でダウンロード (19312K) -
小田島 壽男, 北山 實1988 年 74 巻 5 号 p. 855-862
発行日: 1988/05/01
公開日: 2009/05/29
ジャーナル フリーAntioxidation mechanism of a newly developed oxidation inhibitor of refractory powder mixture composed of SiO2, Si, SiC, synthetic mica, colloidal silica, surface active agent, and coking bond has been investigated.
During heating, Al2O3 is formed as a result of the decomposition by Si (metallic silicon) of mullite (3Al2O3·2SiO2) contained in refractory powder. Furthermore, the fine SiC powder is oxidized and changes gradually to a protective cristobalite-SiO2 (C-SiO2) layer which acts as an excellent diffusion barrier to oxygen from atmosphere. The protective C-SiO2 is not formed from the C-SiO2 which is added in the oxidation inhibitor but is formed through the oxidation process of the SiC.
On the other hand, Al2O3 which is formed by the decomposition of mullite becomes Al2O3·SiO2 in combination with SiO2. On the steel surface, however, Al2O3 becomes highly protective FeO·Al2O3or 3FeO·Al2O3·3SiO2 layer and, at the same time, it prevents the formation of a low melting point material such as fayalite (2FeO·SiO2).
It has been clarified that this oxidation inhibitor exhibits the excellent antioxidability due to superposed effect of above-mentioned reactions.抄録全体を表示PDF形式でダウンロード (12039K) -
草開 清志, 土岐 浩之, 朝見 浩治, 石黒 隆義, 大岡 耕之1988 年 74 巻 5 号 p. 863-870
発行日: 1988/05/01
公開日: 2009/05/29
ジャーナル フリーIn order to elucidate the phenomena and mechanisms of oxidation of Fe-(9, 17%)Cr alloys in Ar-10%H2O atmosphere at 1 000-1 400 K, the thickness and the morphology of scales formed were investigated.
The scales usually consisted of the outer scale and the subscale. The oxide phases of these scales were identified as FeO and the mixtures of FeO and FeCr2O4, respectively. With the increase in Cr content in the alloys the rate of the total oxidation decreased, but the rate of the subscale formation increased.
At all the temperatures parabolic kinetics was observed in the subscale formation, and its apparent activation energies were estimated to be 141 kJ/mol for Fe-9%Cr alloy at temperature above 1 100 K and 214 kJ/mol for Fe-17%Cr alloy at temperature above 1 000 K, respectively. The rate determining diffusion elements were considered to be Fe in FeO for the former alloy and Fe and Cr in α phase for the latter alloy.
As for the subscale configurations, in Fe-17%Cr alloy only a continuous subscale formation was observed, whereas in Fe-9%Cr alloy the characteristic subscale was observed to form periodically. The periodic growth of FeO and FeCr2O4 can be explained by a Liesegang phenomenon, because the kinetics of the subscale formation is parabolic and the subscale formed periodically obeys JABLCZYNSKI'S relationship.抄録全体を表示PDF形式でダウンロード (20917K) -
草開 清志, 土岐 浩之, 石黒 隆義, 大岡 耕之1988 年 74 巻 5 号 p. 871-878
発行日: 1988/05/01
公開日: 2009/05/29
ジャーナル フリーThe oxidation of Fe-(9, 36%)Ni alloys at 1 000-1 400 K has been studied in Ar-(1, 5, 10%)H2O atmosphere using metallographic and electron probe microanalysis techniques.
The scales consisted of the outer scale and the subscale which had a typical substructure of intergranular oxide zone and a metal/oxide mixed zone. The oxide phase in each scale was identified as FeO. With the increase in Ni content in the alloys the total oxidation rates decreased, but the growth rates of subscale increased.
The oxidation rates and morphologies of the scales did not depend on the partial pressure of H2O in the range between 1 and 10 percent in Ar gas.
At all the temperatures the subscales grew according to a parabolic rate law, and the apparent activation energies for the processes were estimated to be 129 kJ/mol for Fe-9%Ni alloy at temperature above 1 100K and 111 kJ/mol for Fe-36%Ni alloy at temperature above 1 000 K, respectively. The rate determining diffusion element in these alloys was considered to be Fe in FeO.抄録全体を表示PDF形式でダウンロード (10456K) -
榊原 瑞夫, 斉藤 俊明, 伊藤 英明, 井上 靖介, 乙黒 靖男1988 年 74 巻 5 号 p. 879-886
発行日: 1988/05/01
公開日: 2009/05/29
ジャーナル フリーUsing a steam corrosion testing apparatus operating under almost the same steam conditions as those in actual boilers, the influences of temperature and pressure (especially above critical pressure) on steam corrosion were investigated for austenitic heat-resisting steels such as SUS 347HTB, 17-14CuMo, and the newly-developed 20Cr-25Ni and 22Cr-35Ni steels for advanced fossil steam plants.
Corrosion loss in weight increases with increase in steam pressure and temperature. Increasing Cr and Ni content improve the corrosion resistance. Concentration of Cr in inner scale, (Cr, Fe)2O3, increases with Cr content of steel. This causes the higher resistance to steam corrosion. A Ni-enriched layer formed at the Cr2O3/metal interface contributes to the improvement of steam corrosion resistance. The Ni concentration in the layer becomes higher as steels contain higher Ni. Structural investigation of the scale cross sections shows that considerably large amounts of voids and cavities are produced in the scale of SUS 347HTB and 17-14CuMo steels corroded in steam at high temperature and pressure.抄録全体を表示PDF形式でダウンロード (23298K) -
近藤 義宏, 松村 智秀, 行方 二郎, 山口 泰広, 田中 勝, 半谷 文雄1988 年 74 巻 5 号 p. 887-894
発行日: 1988/05/01
公開日: 2009/05/29
ジャーナル フリーThe degradation of mechanical properties of SUS 304 during high temperature exposure were investigated by comparing as solution treated specimen with the specimen serviced for 120 000 h in an ethylene plant. Additionally, a restoration of mechanical properties was examined by applying the re-solution treatment to the specimen serviced for the prolonged time, and the microstructural change which affected the degradation was discussed. There was little difference in short time tensile properties among the above three different specimens, except for rupture ductility. More than half decreases in a creep resistance, a creep rupture strength and an impact property were detected in serviced specimen. All these properties, however, could substantially be restored by the application of re-solution treatment to the serviced specimen. The degradation of these mechanical properties during high temperature service were mainly caused by the intergranular precipitation of a sigma phase, and the decrease in density of carbide precipitates, accompanied with the intergranular precipitation of a sigma phase.抄録全体を表示PDF形式でダウンロード (28757K) -
柴田 浩司, 坂本 久樹, 藤田 庫造, 藤田 利夫1988 年 74 巻 5 号 p. 895-902
発行日: 1988/05/01
公開日: 2009/05/29
ジャーナル フリーTensile deformation behavior of metals at very low temperatures has been investigated using mainly Fe-42%Ni alloy in order to make sure the applicability of the computer simulation method presented by the authors and to clarify effects of testing conditions on serration. The amount of elongation accompanied with each load drop in serration increased with the increase in deformation rate and with the decrease in gauge length. Hourglass type specimen showed serration similar to that observed in specimens with smoothly reduced section. Serration was smaller in liquid He(II) than in liquid He(I). All these characteristics of serration observed experimentally were produced by computer calculation. Using computer simulation, it was clarified that the increase in thermal conductivity and diffusivity decreased the amount of elongation accompanied with load drops in serration. Simulation also showed that work hardening played an important role in determining serrated deformation behavior at very low temperatures. However serration was observed even when work hardening was not considered in calculation and specimen was deformed only at the central region of the specimen. Deformation behavior observed experimentally was discussed using such results obtained by simulation.抄録全体を表示PDF形式でダウンロード (1361K) -
小林 俊郎, 山本 勇, 上村 正樹1988 年 74 巻 5 号 p. 903-909
発行日: 1988/05/01
公開日: 2009/05/29
ジャーナル フリーIn this paper, the validity of dynamic elastic-plastic fracture toughness Jd value by the developed evaluation system is studied on the steel for reactor pressure vessel. The effectiveness of the new system for the evaluation of the dynamic fracture toughness is also examined and proved on other kinds of materials such as aluminum alloy, Ti alloy, ductile cast iron and various steels.
Moreover, the simple formura for the calculation of the specimen compliance (Cs) under dynamic loading condition, which is necessary for the correction of the crack initiation energy whenJd is evaluated, is presented.
Elastic-plastic fracture toughness is generally affected by the specimen size. The valid condition for the specimen size under static loading condition is defined in ASTM E813-81. The valid condition for the specimen size determined under dynamic loading condition based on the same procedure appears severer than that of ASTM E813-81. However, it is clarified that the valid dynamic elastic-plastic fracture toughness (JId) is possible to obtain from small specimen such as the standard Charpy size one with the side grooves.抄録全体を表示PDF形式でダウンロード (1123K) -
上野 正勝, 伊藤 亀太郎1988 年 74 巻 5 号 p. 910-917
発行日: 1988/05/01
公開日: 2010/01/15
ジャーナル フリーThe effect of N, Ti and B on the hardenability of low and middle carbon steels has been studied, in order to make clear the optimum condition for obtaining the maximum hardenability of boron(B)-steels. The main results are as follows:
(1) The hardenability of B-containing steel is expressed by the following equation:
In the case of [B] ≤5 ppm, logVC-90=logVC-90°-0.14 [B], and when [B] ≥5ppm, VC-90=0.2VC-90°.where VC-90 is the hardenability defined as critical cooling rate (°C/s) at which 90% of martensite is formed during cooling in B-containing steel, and VC-90°is the hardenability as shown above in the base steel (B-free steel), and [B] is soluble B content (ppm). This means that the effect of B becomes maximum and constant when soluble B content exceeds 5 ppm.
(2) The B-precipitate observed by α-autoradiography can be considered as BN because that the resolve temperature of the B-precipitate coincidents well with that of BN. Therefore, the amount of BN and/or resolved B can be calculated by widely used solubility product of B-N.
(3) Boron-factor (fB), defined by GROSSMANN, is a function of the hardenability of the base steel (B-freesteel) as well as [B] as shown below.
[B] ≤5ppm, fB=1-F/b·DI°
where, F is a function of [B], and b is constant, DI° is the hardenability expressed by ideal critical diameter of the base steel.抄録全体を表示PDF形式でダウンロード (7237K) -
上野 正勝, 伊藤 亀太郎1988 年 74 巻 5 号 p. 918-924
発行日: 1988/05/01
公開日: 2009/05/29
ジャーナル フリーAccording to GROSSMANN'S equation, the effect of alloying element on the hardenability of a steel is expressed in terms of the multiplying factor. Its reliability, however, becomes doubtful since it was confirmed that B-factor is not a function of only B-content. Therefore, in order to confirm whether GROSSMANN'S equation is reliable or not, the relation between a multiplying factor of different alloy element and its content has been investigated. The results obtained are as follow:
1) The multiplying factor fX is a function of DS as well as content of alloying element X. DS is the hardenability of the steel before addition of alloying element. X. With increasing DS, fX becomes smaller.
2) Boron factor, fB, is a function of DI° and shown as follows,
fB=1+1.6/DI°, where DI° is the hardenability expressed by ideal critical diameter of B-free steel.
3) Accordingly, GROSSMANN'S equation is not always realized. When DS is smaller than 2 inch and the hardenability of the steel after alloying element added is less than 33.5 inch, GROSSMANN'S equation is available. 4) There is more intimite relation between the critical cooling velocity and alloy content, X than between DI and X. DI is ideal critical diameter of a steel.抄録全体を表示PDF形式でダウンロード (1122K) -
吉田 勝彦, 佐野 幸吉, 佐藤 駿1988 年 74 巻 5 号 p. 935-935,939
発行日: 1988/05/01
公開日: 2009/05/29
ジャーナル フリーPDF形式でダウンロード (495K)
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