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66 巻, 6 号
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小野 陽一, 酒井 敦1980 年 66 巻 6 号 p. 601-607
発行日: 1980/05/01
公開日: 2010/01/18
ジャーナル フリー溶融Fe-Cr合金およびFe-Cr-Ni合金中のCrの拡散係数を1 5500℃において拡散対法によつて測定して,次の結果を得た.
(1)Fe-Cr合金中の相互拡散係数DFe-Crは0～15 at%Crの濃度範囲で次の実験式で表される.
DFe-Cr×105=3.36-20.9NCr+171N2Cr,cm2/s
(2)Ni濃度4at%,Cr濃度0～12at%のFe-Cr-Ni合金中のCrの主拡散係数DCrCrはDFe-Crの1.3～1.9倍で,Niの添加によつてCrの拡散は速くなる.また,副拡散係数DCrNi,DNiCr,を推算した結果,これらは負の値をとり,その絶対値は主拡散係数にくらべて1オーダ小さいことがわかつた.抄録全体を表示PDF形式でダウンロード (1082K) -
山本 正道, 加藤 栄一1980 年 66 巻 6 号 p. 608-617
発行日: 1980/05/01
公開日: 2010/01/18
ジャーナル フリーThe rates of evaporation of alloying elements from Fe-Cu, Fe-Sn and Fe-Cr melts under vacuum have been investigated by using an experimental apparatus which was made up of a LANGMUIR'S evaporation cell and of target plates for collecting evaporated material. These melts were so heated as to change stirring conditions by resistance heater or high frequency induction.
The evaporation rates are of first order with respect to all the alloying elements. The evaporation from Fe-Sn systems is mainly controlled by the evaporation step on the surface. However, in the cases of Fe-Cu and Fe-Cr systems, both the evaporation step and the diffusion step through the liquid boundary layer are rate controlling, i.e. in these systems, the total evaporation process is of mixed. controll.
The surface concentration of these alloying elements was obtained by analyzing the condensed material on the target plates. The observed values are in good agreement with the theoretical values based on the model proposed by R. G. WARD. This agreement implys that the vaporization coefficients of these alloying elements are unity.
When tin which is surface active element is evaporated from the specimen, surface movement due to surface pressure (Marangoni effect) is observed, and the mass transfer coefficient is increased.抄録全体を表示PDF形式でダウンロード (1437K) -
塗 嘉夫, 大橋 徹郎, 広本 健, 北村 修1980 年 66 巻 6 号 p. 618-627
発行日: 1980/05/01
公開日: 2009/06/19
ジャーナル フリーIn order to evaluate theoretically and prove the effect of REM and Ca-sulphides on heterogeneous nucleation, investigations have been made to find how REM addition influences the solidication microstructure of ingots and continuously cast slabs.
Some characteristics of REM-added steel compared with ordinary steel are as follows:
1) Primary dendrite arm spacing is narrower.
2) Primary dendrite arms are shorter, and they exist more in number.
3) The growth direction of dendrite arms is less oriented.
4) The micro-segregation of C, S, P, Si, and Mn is less.
It is concluded that new primary dendrite arms are generated due to the hetrogeneous nucleation by REM addition in the region of comparatively small supercooling near liquid-solid interface.抄録全体を表示PDF形式でダウンロード (8122K) -
塗 嘉夫, 大橋 徹郎, 広本 健, 北村 修1980 年 66 巻 6 号 p. 628-637
発行日: 1980/05/01
公開日: 2009/06/19
ジャーナル フリーVarious characteristics were observed in the solidification macrostructure of ingots and continuously cast slabs treated with REM.
The results are as follows:
1) REM addition brings about diminition of macro-segregation, enlargement of equiaxed zone, and reduction of loose structure.
2) The starting position of the formation of the inverse V-segregation moves toward the center of ingot and the segregated area expands. The length of segregation line and the segregation ratio are reduced.
3) By autoradiographic observation, large differences in macrosolidification rate are not observed, however, mushy zone at the bottom of an ingot is formed earlier.
4) REM-oxides, sulphides, and oxysulphides are mainly precipitated in dendrite arms. The constituents of inclusions are varied by the methods of REM addition.
Non-metallic inclusions formed by REM addition seem to act as nucleation catalyst and thus improve not only the microstructure but also the macrostructure of the casts.抄録全体を表示PDF形式でダウンロード (7797K) -
竹内 英麿, 森 久, 池原 康允, 駒野 忠昭, 柳井 隆司1980 年 66 巻 6 号 p. 638-646
発行日: 1980/05/01
公開日: 2009/06/19
ジャーナル フリーThe effects of electromagnetic stirring on cast structure of continuously cast SUS 430 slabs have been investigated in order to improve ridging of sheets by grain refinement of cast structure.
The results are summerized as follows:
(1) As stirring intensity increases, equiaxed crystal zone enlarges. Grain refinement of cast structure is influenced considerably by super heat (ΔT) of molten metals and even if stirring intensity increases equiaxed crystal zone hardly enlarges when ΔT reaches a certain temperature. Alternate stirring mode is most suitable for stirring. The effect of super heat on grain refinement of cast structure can be relieved by falling position of stirrer, but ratio of equiaxed crystal zone decreases. Suitable stirring conditions for high ratio of equiaxed crystal zone above 60% are found.
(2) As ratio of equiaxed crystal zone increases ridging of sheets from continuously cast SUS 430 slabs are improved. Ratio of equiaxed crystal zone above 50% is necessary to obtain almost the same ridging as sheets from ingots.抄録全体を表示PDF形式でダウンロード (9919K) -
伊藤 洋一, 升光 法行, 松原 嘉市1980 年 66 巻 6 号 p. 647-656
発行日: 1980/05/01
公開日: 2009/06/19
ジャーナル フリーThe formation mechanism of MnS-type inclusion in steel was investigated on the basis of the experimental results with the effects of sulfur content and cooling rate on the morphology of sulfide, the relation between the solidification structure and the distribution of sulfides, and the observation of formation process of sulfide in steel quenched from various temperatures.
As the result, it became clear that the sulfide which formed an eutectic colony (type II according to SIMS' classification) was increased with the sulfur content in steel and the cooling rate, observed mostly in the region solidified lastly and formed in contact with the melt at the final period of solidification, and also that the non-colony type sulfide (type I, type III and so on) was hardly affected with the sulfur content in steel, decreased as an increase of cooling rate, observed mainly around a dendrite and increased remarkably after the finish of solidification.
These results can be explained rationally by an idea that the colony type sulfide is formed by the eutectic reaction while the non-colony type sulfide is formed as the precipitate from the solid steel.抄録全体を表示PDF形式でダウンロード (7001K) -
中川 恭弘, 坂本 徹, 山内 勇, 山崎 桓友, 上野 学1980 年 66 巻 6 号 p. 657-666
発行日: 1980/05/01
公開日: 2009/06/19
ジャーナル フリーHot rolling and hot-band annealing conditions seem to be very important factors to produce the final sheet having a better deep drawability and fewer surface defects for Ti stabilized 17Cr stainless steel.
Two kinds of experiments were performed to investigate
(1) the effect of finishing temperature with and without hot-band annealing on the plastic strain ratio (r value) of the final sheet,
(2) the effect of finishing temperature and hot-band annealing condition on the ridging tendency of final sheet, and obtained the following results.
Excellent r values are obtainable by decreasing the finishing temperature without hot-band annealing. But pronounced ridging is formed by omitting the hot-band annealing.
Ridging can be diminished by eliminating the band structure which is formed in the center layer of the hot rolled sheet, and the elimination can be attained with a combination of low finishing temperature and propriate hot-band annealing temperature.
The lower finishing temperature is favorable as it facilitates the recrystallization of the band structure with a lower annealing temperature.
The hot-band annealing temperature must be high enough to complete the recrystallization of the band structure, but not be so high as the grain coarsens to become an origin of the orange peel.
The appropriate annealing temperature depends on hot rolling condition and Ti contents.抄録全体を表示PDF形式でダウンロード (10467K) -
萩原 益夫, 河部 義邦1980 年 66 巻 6 号 p. 667-676
発行日: 1980/05/01
公開日: 2009/06/19
ジャーナル フリーA study was conducted to determine the effect of cold rolling prior to aging on the strength and toughness of an ultrahigh strength 13Ni-15Co-10Mo maraging steel. The smooth tensile strength of cold rolled and aged maraging steel increased continuously with increasing amount of cold reduction. The cold rolled maraging steel exhibited anisotropy in properties: the tensile strength in the transverse direction was higher than in the longitudinal direction, whereas the reduction of area and elongation showed lower values in the transverse direction. The notch tensile strength and plane strain fracture toughness KIC also increased with increasing amount of cold reduction, taking maximum values at the 60-70% reduction. For example, longitudinal KIC value increased from 34 MPa·m1/2 for 0% reduction to 63 MPa·m1/2 for 70% reduction. The large KIC increase was attributable to the formation of delamination cracks running parallel to the rolling plane. The KIC test specimen might behave as the sum of a number of thin plates in the presence of the delamination cracks and each thin plate might fracture under the plane stress condition. From these results, it was concluded that the good combination of the strength and toughness could be obtained at the 60% cold reduction.抄録全体を表示PDF形式でダウンロード (10123K) -
添野 浩, 田口 和夫1980 年 66 巻 6 号 p. 677-684
発行日: 1980/05/01
公開日: 2010/01/18
ジャーナル フリー得られた結果を要約すると次のとおりである.
(1)245kg/mm2級マルエージ鋼を475℃で100minあるいは250min時効し,低歪み速度の引張りで延性が減少する試料について,室温空気中で定荷重負荷遅れ破壊試験を行うと,1mm/minの引張りで得られる強度より小さい負荷応力でおくれ破壊現象を示す.長時間の時効で延性の歪み速度依存性を示さなくなつた試料では,明らかにおくれ破壊に対する抵抗が改善される.
(2)245kg/mm2級マルエージ鋼の場合,整合析出相の生成が多いような時効条件の試料では引張性質の歪み速度依存性が顕著である.475℃で25,10,250min時効した試料において典型的な水素脆性の特徴がみられる.すなわち引張りの際に形成される応力集中のみによつては延性が劣化せず,応力集中領域に水素が拡散してクラックを発生させるために延性が劣化する.
400℃においても約190kg/mm2以下では,水素脆性が関与しなければ比較的高い延性を示す.しかし約200kg/mm2以上に達すると,引張変形で形成される強い応力集中の影響で延性の低い破壊をおこす.時効温度を425℃,450℃のように漸次高温にすると,高い強度レベルまで時効硬化しても引張変形で形成される応力集中で延性が劣化する傾向は減少し,応力集中領域に水素が拡散して延性劣化をひきおこす影響が明らかになる.
(3)475℃で25～10000min時効した試料の-76°～150℃における強度の温度依存性は,時効時間が短く,整合析出相が多いと推定される試料において大きく,長時間の時効で転位の運動により剪断されない硬い析出相を多く含有する試料において小さい.
(4)280kg/mm2級マルエージ鋼においては,整合析出相が多い場合および過時効の条件でも引張性質の歪み速度依存性が顕著である.500℃時効で最高強度に達する500min時効および過時効に相当する525℃-500min時効試料などにおいて,典型的な水素脆性の特徴が認められた.
245kg/mm2級マルエージ鋼の場合と同様,整合析出相によつて十分高い強度レベルに硬化されれば引張り変形で形成される強い応力集中の影響で延性の小さい破壊をおこす試料があらわれ,このような場合延性の歪み速度依存性が明らかでなくなるが,強度がそれほど大きくなければ応力集中の形成とそれへの水素拡散によつて延性の劣化がおこる.抄録全体を表示PDF形式でダウンロード (1493K) -
小林 洋, 白沢 秀則, 自在丸 二郎1980 年 66 巻 6 号 p. 685-692
発行日: 1980/05/01
公開日: 2009/06/19
ジャーナル フリーA systematic study has been made of the effects of Cr and Zr on the yield strength of steels in order to develop super mild steels. The steels studied have almost the same chemical composition as commercial Al-killed mild steels except for the addition of Cr and Zr.
The yield strength of the hot rolled steels decreases with Cr content and becomes the lowest at about 0.35wt%Cr. It also decreases with Zr content up to 0.12wt%.
The relation of grain size and yield strength (σy) of the steels has been investigated in order to determine the parameters of σ0 and Ky in Hall-Petch relation expressed as σy=σ0+Kyd-1/2, where σ0, Ky and d have usual meanings. σ0 and Ky have been discussed in terms of Cr and Zr contents.
Cr addition continuonsly increases Ky but decreases σ0. In contrast, Zr addition decreases Ky and provides little effect on σ0. The variations of σ0 and Ky can be attributed to the carbon and nitrogen contents in solution and to the area fraction of pearlite formed at the grain boundaries, respectively.
It has been concluded that the proper combination of Cr and Zr decreases both σ0 and Ky and results in a super mild steel with an extremely low yield strength of about 10kg/mm2.抄録全体を表示PDF形式でダウンロード (3074K) -
柴田 俊夫, 竹山 太郎1980 年 66 巻 6 号 p. 693-701
発行日: 1980/05/01
公開日: 2009/06/19
ジャーナル フリーProbability distribution of failure times of stress corrosion cracking of 17Cr-11Ni stainless steel under constant stresses of 5 to 30 kg/mm2 in 25%, 35%, and 45% MgCl2 solutions at their boiling temperature has been analysed by using the Weibull probability paper which is widely used in reliability engineering. Probability distribution of failure times was found to be described as single or composite Weibull distributions. The composite distribution consisting of mode 1 and mode 2 distributions is found at the low stress conditions. Mode 1 is observed at the earlier failure time region and its shape parameter is larger than unity, depending on the stress and temperature examined. On the other hand, the shape parameter of mode 2 which is observed in the latter region of failure times shows almost a constant value of unity. The condition which gives the shape parameter of unity is likely to correspond to a chance failure or random occurence of crack initiation, while the shape parameter larger than unity indicates a wearout failure which seems to correspond to crack propagation. Thus, the type of distribution of failure times is likely to connect with the failure mode, i.e., crack initiation or propagation.抄録全体を表示PDF形式でダウンロード (6327K) -
川野 正和, 石田 毅, 蒲池 一義1980 年 66 巻 6 号 p. 702-709
発行日: 1980/05/01
公開日: 2009/06/19
ジャーナル フリーSince the method of X-ray stress measurement can be done by non-contact and non-destructive state, we can easily perform the measurement even if the temperature is high such as a few hundreds degree.
In this paper the thermal stress on heated clad steel by X-ray was measured. The result was that we could perform good stress measurement and could find a clear thermal stress cycle at even such a high temperature as 560°C.
Experimental results are as follows:
1) The clad steel hearted up to a temperature of 560°C showed a fine X-ray profile and gave a good correlation on 2θ-sin2ψ diagrams, so we could perform thermal stress measurement by the usual method.
2) In the heating process the thermal stress explained by thermal-expansion coefficient showed thermal stress explained by thermal-expansion coefficient showed thermal stress cycles, giving a terperature loop.
3) The stress value varied by removal of oxide film.抄録全体を表示PDF形式でダウンロード (2492K) -
伊藤 幸良, 高尾 滋良, 岡島 忠治, 田代 清1980 年 66 巻 6 号 p. 710-716
発行日: 1980/05/01
公開日: 2009/06/19
ジャーナル フリーIn order to improve the solidification structure of type 430 steel, alloying and inoculation were tested.
Among used alloying elements, Ti is most effective for formation of equiaxed zone, and this effect is considered to be attributed to TiN as nuclei. Ratio of equiaxed zone is related to quantity of TiN.
Co-borate and other borates induce the local temperature drop by thermal decomposition in liquid steel, and then improve the solidification structure. So these inoculators must be used at casting stage.抄録全体を表示PDF形式でダウンロード (6937K) -
中沢 一1980 年 66 巻 6 号 p. 717-723
発行日: 1980/05/01
公開日: 2009/06/19
ジャーナル フリーPDF形式でダウンロード (1340K) -
武内 寿久禰1980 年 66 巻 6 号 p. 724-729
発行日: 1980/05/01
公開日: 2009/06/19
ジャーナル フリーPDF形式でダウンロード (1377K) -
平川 誠一1980 年 66 巻 6 号 p. 730-733
発行日: 1980/05/01
公開日: 2009/06/19
ジャーナル フリーPDF形式でダウンロード (1031K) -
稲垣 裕輔, 柚鳥 登明, 小川 陸郎1980 年 66 巻 6 号 p. 734-736
発行日: 1980/05/01
公開日: 2009/06/19
ジャーナル フリーPDF形式でダウンロード (2517K) -
古茂田 敬一, 江見 俊彦, 篠崎 義信, 細木 繁郎, 河野 力1980 年 66 巻 6 号 p. 737-754
発行日: 1980/05/01
公開日: 2009/06/19
ジャーナル フリーPDF形式でダウンロード (3517K) -
尾崎 太, 小林 一彦, 雀部 実, 中西 恭二, 郡司 好喜, 藤井 徹也, 尾崎 万, 拝田 治, 檀 武弘, 水流 徹, 辻川 茂男, ...1980 年 66 巻 6 号 p. 755-761
発行日: 1980/05/01
公開日: 2009/06/19
ジャーナル フリーPDF形式でダウンロード (1691K)
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