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Volume 29, Issue 10
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[in Japanese], [in Japanese]1960 Volume 29 Issue 10 Pages 777-786
Published: October 25, 1960
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSDownload PDF (898K) -
Its Applications for Welding EngineeringT. Sato1960 Volume 29 Issue 10 Pages 787-798
Published: October 25, 1960
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSMelting phenomenon is accompanied with phase change. Hence we introduce in ordinary theory of heat conduction latent of fusion, and obtain numerical solutions of one-dimentional non-liner differential equations under various conditions for such a theory. As results, it becomes clear that the effect of latent heat of fusion is relatively large, especially discrepancy of size of melting region by ordinary theory from by our theory is important, for example in non-stationary melting of Al it amounts to nearly 40% under some conditions.
Next we discuss problems of welding engineering according to informations obtained from our theory. In the second report we shall treat stationary melting phenomena.View full abstractDownload PDF (747K) -
On 60 and 90kg/mm2 High Tensile SteelsH. Sekiguchi, M. Inagaki, K. Inomiya1960 Volume 29 Issue 10 Pages 799-804
Published: October 25, 1960
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSIn former reports the authors described on many mild steels and Mn-Si type high tensile steels, of which tensile strengths are below about 57kg/mm2. In the present report, the authors describe on high tensile steels YF and YG which have the tensile strength of about 60 kg/mm2 and contain small amounts of Ni, Cr, Ti and V besides Mn and Si, on the heat-treated Mn-Si type steel "2HA" which has been water-quenched and tempered and has tensile sterngth of about 60 kg/mm2, and furthermore on a heattreated steel "DT" made on trial, which has the tensile strength of about 90kg/mm2 and containing small amounts of various alloying elements and is analogous to the steel T-1 in U.S.A.
(1) On the non-notch bending tests of the steels as received, the steel of which tensile strength is higher, has generally the larger absorbed energy as in the report 5.
(2) On the specimens which have been subjected to thermal cycles of maximum heating temperature 1350°C, the bended angle by impact and slow bending becomes lower in the case of shorter cooling times for all steels used. The absorbed energy by impact bending test at 0°C tends to become higher with the decrease of cooling time for all steels used.
(3) The bad effects of carbon on the non-notch bending test are relaxed by addition of a small amount of suitable alloying elements.
(4) The reduction of area by tensile test began to lower in the case of steel specimen cooled with about C'f cooling time, but the elongation began to lower from the case of a longer cooling time and lowered slowly with the decrease of cooling time to about 8% at the neighbourhood of C'f.View full abstractDownload PDF (523K) -
H. Kihara, H. Suzuki, M. Shimizu1960 Volume 29 Issue 10 Pages 805-811
Published: October 25, 1960
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSA study has been made of the effects of manual weld heat input and plate thickness on the cooling rates at the bond of various weld beads which were deposited on a chromium-nickel stainless steel type 304 with a E347 stainless steel covered electrode of 4 mm diameter.
Cooling rate was determined from weld thermal curves which were measured at the weld bond with specimens either of uniform thichkness or of tapered thickness along the weld line.
The result is summarized as follows;
1) With regards to the two kinds of conventional parameters of weld heat input, I/V and I/√V where I is welding current and V is welding speed, the parameter I/V proved to be more useful for correlation of cooling rates, while I/√V more favourable for cross sectional area of weld bead.
2) The cooling rate in bead welding on stainless steel increased rapidly as the bead length became shorter than about 30 mm.
3) The effects of temperature concerned (T), preheating temperatute (T0), welding current (I), welding speed (V) and plate thickness (t) on the cooling rate at the bond of a bead weld were found to be satisfactorily correlated by an empirical parameter P,
P=( T-T0/ I/V )1.6(1+ 2/π arctan t-t0/α), (t0 and a are constant) and the cooling rate CR (°C/sec)=0.20×P0.85, which may be approximated by a simpler relation, CR=0.067P.
4) The cooling rate in the first layer deposited in a double-Vee groove weld was found to be practically identical to that in a long bead which was welded on the same thickness with the same welding condition. However, the cooling rate in a single Vee groove weld was smaller.
5) As the plate thickness was increased, the cooling rate was saturated to a constant value. The plate thickness of saturation is about 17mm in stainless steel for welding current 90 to 140 A, arc voltage 20 to 22V and welding speed 6 to 8 ipm, although it is about 24mm in carbon steel for a standard welding condition of welding current 170A, arc voltage 24V and welding speed 6ipm.View full abstractDownload PDF (488K) -
Microstructure in Arc WeldingM. Homma, T. Wada, K. Yamaya1960 Volume 29 Issue 10 Pages 812-818
Published: October 25, 1960
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSThe metallographic studies have been performed on the structure of weld heat-affected zone in cast irons. The typical heat-affected zone was obtained by the single-bead test, in which a single bead of about 10 to 12 cm was put on a cast-iron plate of 200×75×20 mm, by using various electrodes under the different conditions. Two layers, ledeburitic and martensitic, are observed in a heat-affected zone, the former varing in its thickness with the melting point of electrode. In martensitic layer, "white" martensite is mainly observed in the case of using cast-iron electrode, whereas in other cases using nickel and low-carbon steel electrodes by the same current, and in a case using cast-iron electrode by a higher current, it shows "dark" martensite. When the carrying speed of electrode is reduced, even in the case of cast iron electrode, primary cementite and troostite acommpanying it are observed in the matrix of dark martensite.
The isothermal transformation diagrams were determined for two species of cast iron and a nodular graphite cast steel. In these diagrams, the boundary line between white and dark martensites was determined below Ms temperature. It is deduced that the two types of martensite are corresponding to fast and slow cooling below Ms temperature, the critical cooling velocity being about 1°C/sec.
There is practically no difference in hardness between the martensitic layers of nickel electrode and of cast-iron electrode, if the welding conditions are the same. The amount of retained austenite was about 17 to 27%, though it reached about 40% in a few microscopic observations, also indicating no appreciable difference between the electrodes.
The diffusion of nickel from deposit metal to the heat-affected zone by the weld thermal cycle is not likely to occur, since the diffusion coefficient of nickel in austenite is relatively low. The superior properties of nickel electrode may be attributed to the high ductility of weld metal, the martensitic heat-affected zone being not essentially different from those of other electrodes.View full abstractDownload PDF (3459K) -
Y. Ito1960 Volume 29 Issue 10 Pages 819-825
Published: October 25, 1960
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSAs the study on 19 Cr-9 Ni based electrode containing Mo, W and Cb for heat resisting 19-9DL Austenitic steel welding, the experiment for weld crack sensitivity and mechanical properties in high temperature was made concerning three kind of electrodes which are called 19-9 WX, 19-8 WM, and 19-12 WM respectively.
19-9 WX contains a few percentage of Mo and W, and 19-12 WM or 19-8 WM contains several percentage of Mn additionally. The result is given as follows.
(1) Tension test of deposit metal and weld joint up to the temperature 650°C shows that the value of tensile strength and elongation of 19-8 WM and 19-12 WM are somewhat higher than the value of 19-9 WX.
(2) Creep test of deposit metal and weld joint under the temperature 650°C with 150 hours shows that the creep strength of 19-8 WM and 19-12 WM is higher than 19-9 WX.
(3) Fatigue test of weld joint under the temperature 650°C shows that the fatigue strength of 19-8 WM and 19-12 WM weld joint is higher than 19-9 WX.
(4) Weld crack sensitivity test shows that the resistance for weld crack of 19-12 WM and 19-8 WM are superior than 19-9 WX, although inferrior 19-9 WX is almost satisfactorily.
(5) The poperties in high temperature of 19-8 WM which has 8% Ni and 19-12 WM which has 12% Ni is almost same.
Above experiments shows that the addition of several pertentage of Mn for 19 Cr-9 Ni Austenitic steel give Satisfactory properties for heat resistant apply up to 650°C, and gives perfect Austenitic Structure for deposit metal.
Moreover, addition of Mn is effective for the suppression of hot crack and σ-phase, and saves the containning of Ni in weld metal to a certain extent.View full abstractDownload PDF (6120K)
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