Tetsu-to-Hagane

Technical Design of Endurable Ceramic

Hajime YAMASHITA

1982 Volume 68 Issue 14 Pages 1865-1869
Published: 1982
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.68.14_1865

JOURNAL FREE ACCESS

Download PDF (834K)
Liquid Metal Embrittlement of Steels during Hot Dip Galvanizing

Masatoshi KIKUCHI

1982 Volume 68 Issue 14 Pages 1870-1879
Published: 1982
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.68.14_1870

JOURNAL FREE ACCESS

Download PDF (4373K)
Reduction of Molten Iron Ore with Carbon

Fumitaka TSUKIHASHI, Masayoshi AMATATSU, Tanekazu SOMA

1982 Volume 68 Issue 14 Pages 1880-1888
Published: 1982
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.68.14_1880

JOURNAL FREE ACCESS

Show abstractHide abstract

The reduction reaction of iron oxide in molten state at 1 500°C and 1 400°C was investigated. By using an X-ray transmission apparatus, the behaviour of molten iron ore was observed continuously. MBR ore was reduced with graphite crucible or carbon in molten iron at 1 500°C and 1 400°C. In the case of reduction in graphite crucible at 1 500°C, the ore melted down until about 60 sec and the sample formed a flat liquid drop until the degree of reduction reached to 30%. As the reduction degree exceeded 30%, the molten iron oxide was expanded by the evolution of gas bubbles. As the degree of reduction exceeded 60%, drops of metallic iron were formed at the surface of molten iron oxide in contact with the wall of graphite crucible. The time change of reduction rate corresponded to the time change of expansion height of molten iron oxide. The area of interface between the molten iron oxide and graphite was estimated as the sum of the area of bottom and side wall of crucible. In the case of using a crucible, the bottom of which is graphite and side wall of which is alumina, the reduction rate obtained was 0.08 g-Oxygen/cm² min.

View full abstract

Download PDF (9175K)
Softening and Melting Behavior of Cold Bond Pellets of Iron Ores with the Use of Portland Cement as Binder

Hirao Go, Mitsuru TATE

1982 Volume 68 Issue 14 Pages 1889-1895
Published: 1982
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.68.14_1889

JOURNAL FREE ACCESS

Show abstractHide abstract

The softening and melting behavior of cold bond pellets of iron ores with the use of portland cement as binder was investigated.
(1) The reducibility of cold bond pellets is generally better than that of fired pellets.
(2) The cold bond pellets have a stronger tendency to shrinkage than fired pellets, due to sintering.
(3) Melt-down behavior of cold bond pellets is characterized by the melting down of slag prior to that of metal. Melt-down slag of cold bond pellets contains much FeO.
(4) For the improvement of melt-down behavior of cold bond pellets, it is effective to decrease cement ratio within the limit that the required crushing strength is ensured, to make basicity higher, to use dolomite as a flux, and to include solid carbon as a reducing agent.

View full abstract

Download PDF (5356K)
Distribution Ratios of Phosphorous, Sulphur and Manganese between Hot Metal and Sodium Carbonate Slag

Satomi YAMAMOTO, Yozo FUJIKAKE, Shoichi SAKAGUCHI

1982 Volume 68 Issue 14 Pages 1896-1904
Published: 1982
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.68.14_1896

JOURNAL FREE ACCESS

Show abstractHide abstract

Reactions of Na₂CO₃ with phosphorous, sulphur and manganese in hot metal contained in an alumina crucible were studied in the temperature range between 1 250 and 1 450°C. Hot metal was oxidized with oxygen in top blowing.
The results showed that simultaneous removal of phosphorous and sulphur from hot metal took place. The distribution ratios of phosphorous and sulphur between hot metal and slag were found to increase lineally with the basicity index of slag, (Na₂O)/1.03(SiO₂) +1.31(P₂O₅), while the distribution ratio of manganese decreased with increase of the basicity index. This decreasing tendency for manganese could be due to higher value of the activity coefficient of manganese oxide in relative higher basicity slag.
The temperature dependency of distribution ratios was examined. Both distribution ratios of phosphorous and sulphur decreased with increase of reaction temperature.

View full abstract

Download PDF (1416K)
Dephosphorization of Molten Iron by Addition of Calcium under Low Argon Gas Pressure

Takaji KUSAKAWA, Manabu OHORI, Koichi KONDO, Keiji YOSHIOKA

1982 Volume 68 Issue 14 Pages 1905-1914
Published: 1982
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.68.14_1905

JOURNAL FREE ACCESS

Show abstractHide abstract

This work was carried out to give scientific support to the dephosphorization of molten iron by metallic calcium. Metallic calcium was added onto molten iron under argon atmosphere the pressure of which is kept higher than that of calcium vapour at experimental temperature of 1 600°C to retain liquid calcium on the meniscus. Calcium-oxide was selected as the crucible material. The experimental results showed that the yield of the added calcium was markedly increased as the argon gas pressure was increased since the rate of vapourization of the liquid calcium into gaseous phase depends on the applied pressure of argon gas. With the sequential addition of calcium at one minute intervals for ten minutes under a argon gas pressure of 8 atmosphere, molten iron was continuously dephosphorized, resulting in 0.0010 wt%P for a low initial phosphorus concentration of 0.0018 wt%. X-ray micro analysis revealed that calcium metal layer existed on top of solidified specimens. This layer can be considered to be the liquid calcium which existed at a higher temperature than the boiling point of calcium under atmospheric pressure. Hydrogen-phosphide(PH₃) was detected in the gaseous mixture obtained by treating the calcium layer with water, so that the dephosphorization products are concluded to be calcium-phosphide (Ca₃P₂).

View full abstract

Download PDF (3166K)
[title in Japanese]

[in Japanese]

1982 Volume 68 Issue 14 Pages 1914
Published: 1982
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.68.14_1914

JOURNAL FREE ACCESS

Download PDF (1797K)
Deoxidation Characteristics and Shape Modification of Deoxidation Products with Al-Ce and Al-Y Complex Deoxidizers

Takehiro DAN, Koki GUNJI

1982 Volume 68 Issue 14 Pages 1915-1921
Published: 1982
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.68.14_1915

JOURNAL FREE ACCESS

Show abstractHide abstract

The purpose of this investigation is to study the deoxidation characteristic of Al-Ce, Al-Y complex deoxidizers and the shape modification of deoxidation products formed in molten iron with the complex deoxidation. The complex deoxidizers used in the present work are ferroalloys consisted of aluminum and cerium or yttrium (110 mol%).
(1) The rate of deoxidation with complex deoxidizer and the minimum oxygen content in molten iron are only a little worse than those for aluminum deoxidation.
(2) The shape of deoxidation products changes from dendritic to grobular with increasing cerium or yttrium content in the complex deoxidizer. At 10 mol% of cerium or yttrium content all deoxidation products become grobular.
(3) The shape modification of deoxidation products, resulting from deoxidation with complex deoxidizer, is explained qualitatively in terms of the formation mechanism of oxide in supercooled melt.

View full abstract

Download PDF (5409K)
A Model Experiment on the Gas Entrainment with Liquid Steel Pouring Stream

Katsuyoshi IWATA, Takao CHOH, Michio INOUYE

1982 Volume 68 Issue 14 Pages 1922-1931
Published: 1982
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.68.14_1922

JOURNAL FREE ACCESS

Show abstractHide abstract

In order to understand the air oxidization of molten steel during teeming, model experiments on the gas entrainment of pouring stream were carried out by using water, ethanol, glycerin aqueous solution and liquid tin.
The breakup length of pouring stream depends on the shape of nozzle, the pouring rate of liquid and the flow of liquid in the tank. In the present experimental range, the amplitude of disturbance at the nozzle exit ε₀ decreases with decreases of nozzle length and pouring rate as indicated by the following equation ;
In(a₀/ε₀) =44.3(l₀/ D₀)^-0.75 (Re) ^-0.1
where a₀ : radius of liquid stream at the nozzle exit, l₀ : nozzle length, D₀ : diameter of nozzle and Re : Reynolds number. The rates of gas entrainment by the pouring stream increase with increasing the height of teeming and the rate of teeming.
The rate of gas entrainment is represented by a model postulating that the pure cylindrical stream entrains no gas and that the gas entrainment occurs by the cavity produced by the collision between the bath surface and the stream surface protuberances. Consequently, taking the cavity radius Rc into account, the rates of gas entrainment are described for all kinds of liquid stream as follows ;
V _g/V_l= 0.02 {(Rc-a) / a₀}³
where V_g : gas entrainment rate, V₁ : volumetric flow rate of stream and a : radius of liquid stream at the teeming height z.

View full abstract

Download PDF (3043K)
Experimental Study on Cooling of a Disk by Impinging Jet of Water

Atsushi KIKUCHI, Yutaka TAMAI, Shoji TANIGUCHI, Teiriki TADAKI, Siro M ...

1982 Volume 68 Issue 14 Pages 1932-1937
Published: 1982
Released on J-STAGE: January 19, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.68.14_1932

JOURNAL FREE ACCESS

Show abstractHide abstract

An experimental study was made to discuss an unsteady heat transfer composed of two steps of the conduction in a disk and the forced convection between an impinging jet of water and the disk.
Temperature changes with time at two points in the disk depended upon its dimensions, diameter of a cylindrical nozzle and average velocity of water in the nozzle. The heat flux in the vertical direction at the interface between the fluid and the disk depended upon the local radius of the disk.
These experimental results were expressed by a heat-transfer model combined with the steady convection and the unsteady conduction. An empirical equation of the heat-transfer coefficient based on the model was presented. However, further study of the steady convection is necessary, because the heat-transfer mechanism under the experimental conditions was not clarified.

View full abstract

Download PDF (843K)
Steady Heat Transfer by Convection between an Impinging Jet of Water and a Disk

Shoji TANIGUCHI, Katsumi SAWADA, Atsushi KIKUCHI, Teiriki TADAKI

1982 Volume 68 Issue 14 Pages 1938-1945
Published: 1982
Released on J-STAGE: January 19, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.68.14_1938

JOURNAL FREE ACCESS

Show abstractHide abstract

Studies of fluid flow and heat transfer in the fluid under a steady-state condition were made to discuss the heat transfer by convection in the system detailed in a previous paper, in which a hot disk is cooled by an impinging jet of water.
First, the fluid-flow characteristics in each of regions I, II and III which have been defined by several workers were discussed. Approximate solutions of the fluid flow in regions II and III were presented, and it was shown that the solutions of the thickness of liquid film were roughly consistent with experimental values.
Secondly, the heat-transfer characteristics in each of three regions were discussed. Theoretical solutions of the heat-transfer coefficients for region I were shown graphically at Pr (Prandtl number) =0.1-100. And also it was shown that theoretical solutions were consistent with numerical ones at Pr =0.5-15. Numerical solutions of the heat-transfer coefficients for regions II and III with the constant heat flux at the fluid-solid interface were obtained. It was shown that their solutions were roughly consistent with experimental values. The heat-transfer coefficients for the system shown in the previous paper could be roughly expressed by the theory in this paper.

View full abstract

Download PDF (1150K)
Influence of Bath Agitation Intensity on Metallurgical Characteristics in Top and Bottom Blown Converter

Tsuyoshi KAI, Kazuo OKOHIRA, Masazumi HIRAI, Shozo MURAKAMI, Nobuo SAT ...

1982 Volume 68 Issue 14 Pages 1946-1954
Published: 1982
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.68.14_1946

JOURNAL FREE ACCESS

Show abstractHide abstract

The influence of bath agitation intensity on metallurgical characteristics in top and bottom blown converter was studied by using 70 ton LD converter and the following main benefits in metallurgical reaction were obtained in comparison with LD converter.
1) In this process, iron oxide in slag and the oxygen content, under the same carbon content at turn down, become lower than in LD process.
2) The aimmed dephosphorization reaction is attainable in spite of lower iron oxide in slag.
3) The manganese content at turn down rises.
4) The controllable range of iron oxide can be more extended by selecting the relative intensity of the top-and bottom blowing conditions, than by LD or Q-BOP process.
It has been shown that the content of iron oxide in slag is controlled by the newly defined operational index of BOG, which means the balance of the formation rate of iron oxide and the feeding rate of carbon as a reducing agent determined by the time required for fully mixing and carbon content.
Balance of Oxygen-and Carbon-feeding rate= Q_O₂S/(W/τ)[%C]

View full abstract

Download PDF (1430K)
On the Protection of Molten Steel from Nitrogen Absorption in Steelmaking Process

Yasuhisa ABE, Mitsuhiko NISHIMURA, Hiroyuki KATAYAMA, Toshinori TAKAHA ...

1982 Volume 68 Issue 14 Pages 1955-1963
Published: 1982
Released on J-STAGE: January 18, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.68.14_1955

JOURNAL FREE ACCESS

Show abstractHide abstract

For the purpose of producing low nitrogen steel by making use of low nitrogen content (712 ppm) of the molten steel at the end point of improved oxygen converter, conditions for protecting molten steel from nitrogen absorption between the end point of converter and casting are investigated.
(1) In the case of low carbon steel, the combination of tapping without adding deoxidizer and ladle metallurgy with consideration of the amount of slag and sealing suppresses the total nitrogen pick up 39 ppm.
(2) The relationship between the order of rate formula of nitrogen absorption and conditions ([N], [O] and P_N₂) is considered. For the steps of reblowing and tapping of low nitrogen molten steel, rate formula of second order would be more suitable. The influence of [%C] on the nitrogen absorption during reblowing and tapping is explained on the result.
(3) In the case of high carbon steel, method of using dry ice for preventing nitrogen absorption during tapping are developed. The optimum condition of using dry ice are studied. It has been possible to produce stably the high carbon steel wire materials of low nitrogen content (2±2 ppm) by using this technique.

View full abstract

Download PDF (1389K)
Cold Model Study to Evaluate the Critical Condition for Channelling Phenomena in Bottom Blowing

Tsuyoshi KAI, Kazuo OKOHIRA, Mitsuo HIGUCHI, Masazumi HIRAI

1982 Volume 68 Issue 14 Pages 1964-1970
Published: 1982
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.68.14_1964

JOURNAL FREE ACCESS

Show abstractHide abstract

Cold model experiments have been made to clarify critical conditions for the occurrence of channelling in bottom blowing. Also, factors controlling the quantity of spitting have been examined by using water and ethyl alcohol as cold bath. Critical bath depth (H_c) at which channelling took place was determined by a weight measuring technique as H^Mes_c and visual observation as H^Obs_c.
Statistical analysis of these data indicates that the critical bath depth[normalized by inner dia. of nozzle (D)] and the quantity of spitting ( W_g) are expressed, respectively, by ;
H^Mes_c / D =5.07(F'_rD)^1/3,
W_g = 10^15.07(F'_rD)^3.83(L₀/ D) ^-6.95(ΔH/D) ^-6.43We^-0.308,
where F'_rD=(ρ_g^v²)/(ρ₁·D·g), v: avarage velocity of gas injected into bath (cm/s), g : acceleration of gravity (cm/s²), ρ_g: density of gas, ρ₁: density of bath (g/cm³), L₀: bath depth (cm), ΔH: distance between the static surface of bath and sponge (cm), We= ρgD·v²>/ σ, and σ is the surface tension of bath (dyn/cm). On the basis of these results, bottom blowing condition suited for an LD converter with bottom blowing is discussed.

View full abstract

Download PDF (912K)
Coupling Phenomena in Molten Iron Alloys and Slags at High Temperature

Yoshio UKYO, Kazuhiro S. GOTO

1982 Volume 68 Issue 14 Pages 1971-1980
Published: 1982
Released on J-STAGE: January 18, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.68.14_1971

JOURNAL FREE ACCESS

Show abstractHide abstract

The magnitude of various coupling effects have been determined in molten iron and slag at high temperature by measuring Soret coefficient, thermoelectric power and interdiffusivity matrix. Soret coefficients of P, Si, Ni, and Cr in molten iron are positive except Fe-10 wt%P alloy, and their absolute values are 10^-310^-4 K^-1. Absolute values of Soret coefficients of several solute oxides in molten CaO-SiO₂-Al₂O₃ and Fe₂O₃-CaO-SiO₂ slag are 10^-310^-4 K^-1. The thermoelectric power of molten CaO-SiO₂-Al₂O₃ slag, measured with platinum electrodes, is 0.31 mv/K and the hot side is positive. Absolute values of interdiffusivity matrix of molten Fe₂O₃-CaO-SiO₂ slag equibriated with air are 2 ×10^-64×10^-7 cm²/s and their cross terms are negative. From these results, the transport coefficients, L_ik have been determined for molten iron alloys and slags.

View full abstract

Download PDF (1641K)
Measurement of Quasi-binary Interdiffusivities of Various Oxides in Liquid Slags

Yoshio UKYO, Kazuhiro S. GOTO

1982 Volume 68 Issue 14 Pages 1981-1986
Published: 1982
Released on J-STAGE: January 18, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.68.14_1981

JOURNAL FREE ACCESS

Show abstractHide abstract

Quasi-binary interdiffusivities of several solute oxides in liquid CaO-SiO₂-Al₂O₃ slag of 4 : 4 : 2 of charge weight ratio and liquid Fe₂O₃-CaO-SiO₂ slag of 2.5 : 3 : 4.5 of charge weight ratio equibriated with air were measured by using the diffusion couple method between 1 350 to 1 450°C. After diffusion runs for 20 or 40 min, the sample was quenched to glassy state and analyzed by a X-ray micro-analyzer. The quasi-binary interdiffusivities obtained from the penetration curves of totally 68 successful diffusion runs can be expressed by the following equations.
( a ) 40wt%CaO-40wt%SiO₂
D _P₂O₅=2.16exp(-55.0/RT)
D _Fe₂O₃=5.45exp(-66.8/RT)
D _TiO₂=2.3Oexp(-58.5/RT)
D _MgO=3.27exp(-23.2/RT)
D _MnO=5.04exp(-57.0/RT)
( b ) 25wt%Fe₂O₃-30wt%CaO-45wt%SiO₂
D _P₂O₅=3.42exp(-57.5/RT)
D _TiO>=9.65exp(-79.6/RT)
D _MnO=1.38exp(-34.1/RT)
D _MgO=4.75exp(-22.5/RT)
D _NiO=3.36exp=(-50.9/RT)
where quasi-binary interdiffusivities and activiation energies are given in the unit of cm² per sec and kcal per mol, respectively.
Of a total 138 diffusion runs, only 68 samples gave normal penetration curves. Other unsuccessful samples contained many small gas bubbles.

View full abstract

Download PDF (900K)
Raman Spectroscopic Study on the Structure of Silicate Slags

Shigeki KASHIO, Yasutaka IGUCHI, Tasuku FUWA, Yuichiro NISHINA, Takena ...

1982 Volume 68 Issue 14 Pages 1987-1993
Published: 1982
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.68.14_1987

JOURNAL FREE ACCESS

Show abstractHide abstract

A Raman spectral study has been carried out on the structure of the glassy and molten states of the binary silicates, Li₂O-SiO₂, Na₂O-SiO₂, K₂O-SiO₂, CaO-SiO₂, SrO-SiO₂ and BaO-SiO₂.
An argon-ion laser beam of 4 880 A has been used as an exciting light for the glassy state and 4 579 Å for the molten state. New discrete Raman lines have been observed clearly in the quenched glassy samples. These spectra are compared with those measured in the crystallized stoichiometric silicates. The silicate formation by mixing basic oxides with vitreous silica induces a shift of the line at 485 cm^-1 toward higher wave number. This shift does not depend on the species of alkali or alkaline earth elements but on the composition of a basic oxide. The spectra of the glassy state exhibit four different peaks in the Raman shifts between 850 and 1 100 cm^-1 corresponding to the number of non-bridging oxygens for each silica tetrahedron unit.
Raman spectra of the alkali silicate systems have been measured below and above their melting points. There is little difference in the spectra between the quenched glassy state and the molten state. The silica tetrahedron complex structure, therefore, is relatively stable in these systems and the Si-O bond stretching and Si-O-Si bending vibrations are not affected by thermal energy up to 1 353 K.

View full abstract

Download PDF (1187K)
Development of Roll Slitting of Hot Slabs

Yoneaki FUJITA, Masaru OKADO, Minoru HIRACHI, Hiroshi WAKASA, Ikuo WAK ...

1982 Volume 68 Issue 14 Pages 1994-2000
Published: 1982
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.68.14_1994

JOURNAL FREE ACCESS

Show abstractHide abstract

Roll slitting of hot slabs is investigated using an experimental mill and a slabing mill. Fundamental characteristics are obtained, such as necessary conditions for slitting, deformation behavior during slitting, and required load and torque to slit. Large deformation of shape, such as camber and increase of thickness near slit surface, causes difficulty during handling and rolling of the slab. Based on these experimental results, two practical slitting processes which prevent deformation of slab arc developed.
Hot rolling test of slit slabs is conducted using a hot strip mill, and its stability during rolling and the quality of hot coils are as good as those of normal hot rolling.

View full abstract

Download PDF (4132K)
A Laboratory Study on the Processing Factors for Cold-rolled Dual Phase Sheet Steels

Takashi FURUKAWA, Hirofumi MORIKAWA, Michio ENDO, Hiroshi TAKECHI, Kaz ...

1982 Volume 68 Issue 14 Pages 2001-2009
Published: 1982
Released on J-STAGE: January 18, 2010

DOIhttps://doi.org/10.2355/tetsutohagane1955.68.14_2001

JOURNAL FREE ACCESS

Show abstractHide abstract

Dual Phase structure formation in the intercritical annealing method is strongly affected by the cooling stage. Role of the cooling stage consists of (a) carbon enrichment into the untransformed austenite, (b) avoidance of pearlite formation and, (c) martensite and retained austenite formation. Significance of a two-stage cooling can be explained on the above basis.
Employment of a rapid heating and a short-time intercritical holding produces a highly bake-hardenable dual-phase steel with a large work-hardening capacity. This phenomenon is supposedly related to a transient state of solute carbon partitioning in the intercritical temperature range.

View full abstract

Download PDF (7894K)
Wear in Liquid Nitrogen and Liquid Oxygen

Hajime SUTO, Byon Sun CHUN

1982 Volume 68 Issue 14 Pages 2010-2018
Published: 1982
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.68.14_2010

JOURNAL FREE ACCESS

Show abstractHide abstract

Development of wear-proof materials for low temperature uses is expected to accompany the advances in cryogenic technologies. In the present paper, the results of sliding wear of several kinds of FCC alloys and Ti alloys against a 0.45%C martensitic steel and a SUS316-type stainless steel in liquid N₂ and O₂ are reported.
(1) The wear loss in liquid N₂ or O₂ was about 1/10 of that in air at R.T..
(2) The general tendency that the harder materials are the more wear-proof was recognized. However, the wear loss of some materials increased by age hardening, and the materials containing insoluble carbides were easily abrased.
(3) The wearing phenomena in liquid N₂ or O₂ may be good examples to which the "delamination" theory proposed by Suh et al. can be applied.

View full abstract

Download PDF (2660K)
Detection and Analysis of Crevice Corrosion-SCC Process by the Use of AE Technique

Shigenori YUYAMA, Teruo KISHI, Yoshihiro HISAMATSU

1982 Volume 68 Issue 14 Pages 2019-2028
Published: 1982
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.68.14_2019

JOURNAL FREE ACCESS

Show abstractHide abstract

Crevice corrosion and crevice corrosion-SCC processes of SUS 304 stainless steel have been detected and analyzed in a 3% NaCl solution at 308 K by the use of AE (Acoustic Emission) technique. The AE detected during the crevice corrosion induced by the polarization scan is shown to arise from hydrogen gas which is evolved inside the artificial crevice. The hydrogen gas evolution is thought to occur when the pH value of the solution contained in the crevice becomes sufficiently low and the potential falls below E°(H₂). It can provide AE, amplitude of which may reach some hundreds μV, measured by the piezoelectric AE sensor that has the maximum sensitivity "6000 V/(m/s)". The SCC test using DCB specimen with the artificial crevice shows, on the other hand, that AE with higher energy than mV level is accompanied with the SCC microcrack initiation which takes place successively after the crevice corrosion. The following three facts suggest that hydrogen embrittlement may be involved in this SCC process ; 1) H₂ gas evolves inside the crevice during the crevice corrosion process, 2) High energy emissions are emanated with the SCC microcrack initiation under plane strain condition, 3) Dissolution of metal does not provide sufficiently high AE energy to detect : Practical methods to apply AE technique to fundamental studies in laboratory and continuous monitoring in engineering structures are also discussed in detail.

View full abstract

Download PDF (3330K)
Stress Corrosion Cracking of Chromium-containing High Manganese Austenitic Steels

Hideaki MIYUKI, Taishi MOROISHI

1982 Volume 68 Issue 14 Pages 2029-2036
Published: 1982
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.68.14_2029

JOURNAL FREE ACCESS

Show abstractHide abstract

Effect of several factors on the IGSCC susceptibility of chromium-containing high manganese austenitic steels has been investigated. As a result, a corrosion resistant high manganese steel to IGSCC has been developed. The mechanism of IGSCC is discussed.
0.4%C-18%Mn-5%Cr steel posesses the susceptibility to IGSCC at HAZ of weldment. The steel heat treated at temperatures from 500 to 900°C shows the susceptibility. IGSCC of the alloy is possible to occur even in pure water as well as in chloride solution. However, solution treatment above the temperature of 950°C prevents the alloy from IGSCC. Chromium depleted zone at grain boundary associated with the precipitation of chromium carbide (Cr₂₃C₆) is seemed to be prefferentially attacked resulting in IGSCC in corrosive media. The prevention of 0.4%C-18%Mn steel from IGSCC is possible to attain if the Cr content lowers below 2.5%.

View full abstract

Download PDF (6928K)
Relation between Oxide Inclusion on the Rolling Track and Flaking

Kazuichi TSUBOTA

1982 Volume 68 Issue 14 Pages 2037-2045
Published: 1982
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.68.14_2037

JOURNAL FREE ACCESS

Show abstractHide abstract

The results stated below have been revealed on the relationship between the plate-like carbides which form immediately under the rolling track and oxide inclusions present on the track for the specimens tested in the ball/washer thrust type rolling contact fatigue testing machine.
1) The plate-like carbides precipitate as carbon diffuses by rolling contact stress in an area of stress concentration between the oxide inclusions on the rolling track and those immediately under the track.
2) In the specimens made of vacuum degassed steel, the plate-like carbides begin to present themselves after approximately 10⁶ stress repetition at P_max of 500 kgf/mm², although its rate depends on amount and size of the inclusions.
3) The oxide inclusions found in specimens of the thrust type tester for rolling fatigue do not have a direct influence on causing cracks as stress concentration source. Their stress concentration effects rather work as intermediary to produce the plate-like carbides.

View full abstract

Download PDF (11141K)
Reduction Test of Micaceous Iron Oxide Fe₂O₃ doped with Na₂O and K₂O

Yoshinobu UEDA, Sogo SAYAMA, Yasunori NISHIKAWA, Yoshikazu SUZUKI, Soi ...

1982 Volume 68 Issue 14 Pages 2046-2048
Published: 1982
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.68.14_2046

JOURNAL FREE ACCESS

Download PDF (3616K)
[title in Japanese]

[in Japanese], [in Japanese], [in Japanese]

1982 Volume 68 Issue 14 Pages 2050-2055
Published: 1982
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.68.14_2050

JOURNAL FREE ACCESS

Download PDF (4018K)
[title in Japanese]

[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...

1982 Volume 68 Issue 14 Pages 2061-2064
Published: 1982
Released on J-STAGE: June 19, 2009

DOIhttps://doi.org/10.2355/tetsutohagane1955.68.14_2061

JOURNAL FREE ACCESS

Download PDF (680K)

Register with J-STAGE for free!