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Volume 38, Issue 4
Displaying 1-10 of 10 articles from this issue
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Masao Mizuno1969 Volume 38 Issue 4 Pages 314-325
Published: April 25, 1969
Released on J-STAGE: August 05, 2011
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Toshio Kitani1969 Volume 38 Issue 4 Pages 326-342
Published: April 25, 1969
Released on J-STAGE: August 05, 2011
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Kazuyuki Minoda1969 Volume 38 Issue 4 Pages 342-358
Published: April 25, 1969
Released on J-STAGE: August 05, 2011
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Kunihiko Satoh, Takeshi Ohnishi1969 Volume 38 Issue 4 Pages 359-371
Published: April 25, 1969
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSTransient thermal stresses of weld heat-affected zones were evaluated by a rigid frame apparatus as shown in Fig. 1. Round bar specimens set into the rigid frame were put to thermal cycles by induction heating and transient thermal stresses were recorded on the oscillograph connected to the loadcell. Four kinds of steel of different mechanical and metallurgical properties were used. The types of applied thermal cycle were single thermal cycle, multi thermal cycles of constant peak temperature type, increasing- or decreasing- peak temperature type (see Figs. 11 a, b).
Test results of the transient thermal stress as a function of temperature are shown in Figs. 6 thru 9, Figs. 12 thru 16, Figs. 18 and 19. Residual stresses as a function of peak temperature applied are shown in Fig. 10 for single thermal cycles and in Fig. 17 for multi thermal cycles. The transient thermal stresses and residual stresses are influenced by the mechanical and metallurgical properties of steels used.
Analysis of mechanical strains during thermal cycles was made using a connected bar-spring model as illustrated in Fig.2 b and a long rectangular plate as in Fig. 23 on they-axis of which an instantaneous plane heat source was applied. The analysis revealed the difference in mechanical strains between the model and the rectangular plate. The transient thermal stresses or elastic strains in plastic zones of the rectangular plate were approximately estimated by both-ends-fixed bar analogy.View full abstractDownload PDF (895K) -
Akio Otsuka, Kin-ichi Nagai, Tetsuro Kawasaki1969 Volume 38 Issue 4 Pages 372-381
Published: April 25, 1969
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSApplication of the slab analogy, the analogy between the deflections of slabs and Airy stress function in a two-dimensional state of stress, to the estimation of the residual stress induced by welding is discussed.
According to the slab analogy, the stress distribution due to the uniform initial strain is to be obtained from the deflections of analogous slab models. Therefore, if we assume that the region of weld metal can be replaced by that of uniform initial strain, the estimation of the distribution of residual stress induced by welding will be made from the deflections of analogous slab models.
Based on this principle, the distribution of residual stress due to welding was found experimentally in several cases. As the experimental technique for the determination of deflections, actually slopes, of the slabs, the reflection-type Moire method was employed.
It is shown by this experiment that this slab analogy-Moire method will be very effective for the estimation of the residual stress distribution due to welding, in view of its good accuracy and experimental convenience.View full abstractDownload PDF (6931K) -
Masahiro Uda, Satoru Ohno, Tsuguyasu Waka1969 Volume 38 Issue 4 Pages 382-392
Published: April 25, 1969
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSThe solubilities of nitrogen in arc-melted and levitation-melted iron and its alloys have been measured and the influence of Cr, Mo and V on the solubility has been determined. It is found that the nitrogen content of the arc-melted pure iron is proportional to the square root of the partial pressure of nitrogen up to 0.4% nitrogen-argon, while above 0.4% nitrogen-argon the content becomes nearly constant, and the arcmelted iron shows about 20 times higher solubility of nitrogen than the leviation-melted iron. This .anomalous solubility may be caused by the activation of atmosphere. The activation of nitrogen may be mainly attributed to the increased concentration of atomic nitrogen in the atmosphere. The dissolved nitrogen was assumed at first as being in equilibrium with the atomic nitrogen which originates from the arc-column by quenching. Then from the statistical-thermodynamical treatment of gas phase and molten iron the temperature of the arc-column was calculated as about 3000°K. This is quite lower than the actual temperature of arc-column, about 6000-10000°K. This and some other experimental facts suggest that the apparent solubility in arc melting may not be true equilibrium property but a steady state concentration between dissolution into and escape from the melt.
In arc-melting in the low nitrogen atmosphere (0.14% N2-Ar), the influence of alloying element on the solubility of nitrogen was quite anomalous. At relatively high nitrogen atmosphere (3% or 5% N2-Ar) it was influenced by the alloying elements in a manner similar to the equilibrium solubility. By levitation melting, the interaction parameters between nitrogen and Cr, Mo and V were obtained at 2140-2240°C as
eN(Cr)=-0.028 (Cr<10%)
eN(Mo)=-0.0051 (Mo<8%)
eN(V)=-0.062 (V<6%)
These values are reasonable in view of those at 1600°C and their temperature dependence.View full abstractDownload PDF (759K) -
Hisashi Hishida, Masakazu Maruyama1969 Volume 38 Issue 4 Pages 393-394
Published: April 25, 1969
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSElenbaas-Heller's equation for a wall-stabilized plasma arc with non-zero plasma gas flow has been solved analytically in order to obtain the radial and the axial current and temperature distributions in a plasma arc column.
The thermal conductivity and the constant pressure specific heat of Ar-gas employed in the equation are approximately expressed in terms of simple functions of temperature and the reliability of the solution is shown satisfactory in comparison with the spectroscopic temperature measurements in a plasma arc column studied by C.F. Knopp and A.B. Cambel.View full abstractDownload PDF (367K) -
Fundamental investigation and practical application to shallow penetration of fillet weldsKeisuke Hashimoto1969 Volume 38 Issue 4 Pages 399-409
Published: April 25, 1969
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSFundamental equations and diagrams of welding penetration are obtained from idealised models of a moving point heat source, and practical application of the theoretical penetration is investigated to predict actual penetration of a fillet welding joint as follows:
(1) Relationship between-welding conditions represented by dimentionless function N and theoretical penetration represented by dimentionless function D is given by the following equations with common parameter ρ:
N=ρ⋅exp(ρ/1+ρ), D=ρ/1+ρ√1+2ρ
N-D diagram obtained from the two equations above is presented as shown in Fig. 2.
(2) Temperature distribution of a infinite plate being welded on both sides simultaneously. is also investigated, and the relationships of welding conditions (N), plate thickness (T) and-theoretical penetration (D) are given by the following approximate dimensionless equations:
1/N=1/ρ⋅exp(ρ/1+ρ)+1/R⋅exp(R-ρ2/1+ρ)
R=√(T-D)2+(ρ2/1+ρ)2
D=ρ1+ρ√1+2ρ
N-D-T diagram and D-T diagram are obtained from the three. equations above as shown in Fig. 4 and Fig. 5 respectively for practical application td simultaneous fillet welding on both sides of a Tee-joint.
(3) Relationship between norminal penetration (d) of actual fillet weld and theoretical penetration
(d) obtained from N-D diagram or N-D-T diagram is given by the following approximate equation (see Fig. 7 and Fig. 8):
d=2.36(d2/h-h/2π)
where, h is leg size of a fillet weld.
(4) Relationships between nominal penetration (d) and effedtive penetration (p) of a fillet welding joint (see Fig. 6) are also given approximately as follows:
for single fillet welding ........................... Ψ1=√(δ+1)(5.828δ-1)-2.414δ
for both-sides welding ........................... Ψ2=1/2δ{√(0.157+1.63δ2)(0.1570.37δ2)-0.157+ δ2}
where, Ψ=p/h, δ=d/h
Ψ-δ diagrams are presented to predict effective penetration as shown in Fig. 13.
(5) The utility of the results shown above is experimentally confirmed by automatic contact arc welding of Tee joint. (see Figs. 9, 10 and 13)
The present paper discusses mainly on shallow penetration of fillet welds, the deep penetration will be discussed in 2 nd report.View full abstractDownload PDF (649K) -
Iwao Onishi, Ikuo Okamoto, Takeshi Ariga, Mituru Arii1969 Volume 38 Issue 4 Pages 410-415
Published: April 25, 1969
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSThe external cathodic polarization curves of each cast alloy such as Al-Sn, Al-Zn and Zn-Sn systems, which were dipped in 3% NaCl aqueous solution, were investigated by a potentiostatic method to determine the corrosion behavior of soft-soldered joint in aluminum. The profiles of the polarization curves were conventionally divided into two categories: straight line and curved line type. The former was seen in Al-Sn system only and this phenomenon was presumed as the cathode reaction of Eyring's protrotopic process, because the value of transfer coefficient calculated by using the measured value in this type was about 0.33 and was nearly equal to that of tin having a cathode control of activation process. The latter was seen in all of metals used as alloying elements and the remainder among the alloys tested here and this phenomenon was considered as the concentration polarization, where a cathode reaction is controlled by a diffusion process of dissolved oxygen. To do this consideration, iL, a limiting current density, was approximately calculated by the following equation introduced by using Fick's-Law.
iL=2⋅F⋅D01/2[O2]⋅t-1/2/√π
Where F is Faraday constant, D0 is the diffusion constant of oxygen, [O2] is the concentration of disolved oxygen, t is the dipping time of sample. While the measured value for iL was decided by appling an overvoltage intercept method to the external cathodic polarization curve.
From the electrochemical measurements mentioned above, it has been concluded that the natural electrode potentials of soldered joints in aluminum were not necessarily the important factor governing the corrosion rate between the aluminum, the various phases in the solder and the layer that forms at the aluminum and solder interface.View full abstractDownload PDF (2863K) -
1969 Volume 38 Issue 4 Pages 421-423
Published: April 25, 1969
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSDownload PDF (1385K)
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