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Volume 35, Issue 6
Displaying 1-5 of 5 articles from this issue
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Effect of Defective Spot Welds on Joint StrengthKimio Kimura, Sadasi Nisino1966 Volume 35 Issue 6 Pages 405-412
Published: June 25, 1966
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSThe previous report has shown the relationship between the internal defects of spot weld and the strength under static or repeated load. Based upon these results, the effects of defective spot welds on joint strength were investigated for multiple spot-welded Al alloy joints, that is, the effects of the factors such as the kind, the number or the distribution of defective spot welds on joints.
As the result of this study, the relationship between the static or fatigue strength of joints and the arrangement of defective spot welds has been established; morever, the degree of influence of the distortion-coefficient or the load-share of spot welds on joints has been clarified.View full abstractDownload PDF (1534K) -
Effect of Transformation Expansion on the Contraction and Reaction Force of Steel WeldmentsKunihiko Satoh, Shigetomo Matsui1966 Volume 35 Issue 6 Pages 413-420
Published: June 25, 1966
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSEffect of transformation expansion on the contraction and reaction force of steel weldments was investigated. Four kinds of steel, a plain carbon steel (MS), high strength steels of 60 kg/mm2 (HT-60) and 80 kg/mm2 (HT-80) tensile strength level and a 9% Ni steel (9N) were selected for experiments (Table 1.). Expansion in contraction curves of weldments was observed in the temperature range of about 700-200°C during cooling, in particular, in HT-80 and 9N steel weldments (Fig. 3 and Table 2). Transformation expansion of overall weld was estimated from dilatometric data on selected steels and their weld metals subjected to welding thermal cycle (Fig. 8). The expansion and temperature range by horizontal tangent points observed in the weld contraction curves were compared with the total transformation expansion and transformation temperature range obtained from dilatometric curves (Fig. 11). The onset of expansion in the contraction curves is delayed and the observed expansion is smaller than the total transformation expansion. The reason is that the increase in contraction depending on the heat-loss in weldments more or less cancels the expansion by transformation. Final contraction of weldments decreases with an increase in transformation expansion of steels (Fig. 12). The trends of the curves of reaction force during cooling are approximately the same as those of the contraction curves.View full abstractDownload PDF (1713K) -
Yoshitaka Matsumura, Masao Mizuno, Kiyokado Nishihara1966 Volume 35 Issue 6 Pages 421-428
Published: June 25, 1966
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSViscosities of molten fluxes depend on their composition and temperature. Since the viscosities of fused fluxes have an important influence on operation of fusion welding and brazing, we measured the vis cosities of KCL-LiCL and KCL-NaCL systems by damped oscillation method with platinum disc.
Since the flow of liquid is a rate process, the viscosity has been treated as such and the activation energy for viscous flow was calculated from equation I.
lnη/ρ=(Nh/Mavge-ΔS‡/R)eΔH‡/RH=AeEvis/RT ………………………………………(1)
η : viscosity, ρ : density of molten flux
Mavg : molecular weight of molten flux,
A . constant,
Evis : activation energy for viscous flow,
The results obtained are summarized as follows.
1. KCL-LiCL system
The isotherms of viscosities against molar composition for system showed negative deviation from addi tivity and a minimum value of viscosity was recognized at 58 mole per cent LiCL. The activation energy for viscous flow showed negative deviation from additivity.
2. KCL-NaCl system
The isotherms of viscosities showed negative deviation from additivity and a minimum value of viscosity was recognized at 70 mole per cent NaCL.
The activation energy showed positive deviation from additivity in the range of 0-40 mole per cent NaCL and showed negative deviation in the range of 40-100 mole per cent NaCL.
These deviations are caused by the interaction of molecules, and the activation energy for viscous flow of molten fluxes mixture may be represent by the equation 2.
Em=x13EA+3x12x2EA⋅+3x1x22EB⋅x23EB ……………………………………(2)
X1 : mole fraction of A.
X2 : mole fraction of B.
EA : activation energy of pure A.
EB : activation energy of pure B.
EA. : activation energy for interactions of
two molecules of A and one of B.
EB. : activation energy for interactions of two molecules of B and one of A.View full abstractDownload PDF (575K) -
Toshisuke Shioya, Senichi Yamada, Yutaka Tarutani1966 Volume 35 Issue 6 Pages 429-438
Published: June 25, 1966
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSWeld joints of austenitic steel and carbon steel are largely used when corrosion resistance and heat resistance are required, such as motor shaft, engine valve, etc. Dissimilar weld joint is attended with change of strength owing to the element diffusion at weld, or with difficulty of machining owing to increase of hardness. Then studies on change of strength and heat treatment after welding are required. When SUS27, austenitic stainless steel, and S45C, carbon steel, are welded by friction welding, movement of certain elements and mechanical properties of the joint are studied for the following cases:
1. as welded
2. exposed 1 hour at 700°C and then air cooled
3. exposed 100 hours at 700°C and then air cooled
4. exposed 1 hour at 850°C and then air cooled
with following results.
Study of element distribution, structure and hardness distribution at weld shows that there is a little element migration across the weld interface. It is almost caused by mechanical agitation of revolving friction during welding, and therefore elements are mixed at the weld interface. The width of the mixed zone is 15μ-40μ at center and 50μ-200μ at the part above 2mm far from center. As for the joint heat treated after welding, elements which have large atomic diameter such as Cr. Ni hardly migrate; while C is diffused from S45C to SUS27, producing decarburized zone on S45C side and carburized zone on SUS27 side. Above a certain length of heating time, carbide precipitates on SUS27 side near the weld interface.
The joints which have been heat treated for short time rupture at base metal of SUS27 except in the case of Charpy impact test. The decrease of Charpy strength, however, little differs from that of similar weld joint, and no influence on strength of dissimilar weld joint can be observed. On the other hand, the joints heat treated for long time rupture at weld in any mechanical tests which prove that the strength dedecreases. This is attended with coarse grain zone of ferrite and precipitation of carbide caused by progress of forming of decarburized zone on S45C side and carburized zone on SUS27 side. It is. therefore, due to the diffusion of C atoms because of difference of chemical composition, not to the fault of friction welding. Moreover, such heating time as causes a decrease of strength is so long, and there is no problem unless the joints are used at a high temperature.View full abstractDownload PDF (15018K) -
Hideo Sasaki, Fujio Tomiyasu, Masami Inoue, Kenji Takahashi1966 Volume 35 Issue 6 Pages 439-453
Published: June 25, 1966
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSWe have successfully fabricated metal lined chemical equipments by means of HABW expolsive welding process, instead of conventional methods such as fusion welding or using clad plates.
The HABW explosive welding process has the following good features that have been considered not practical to date.
1) Joining of different metals is possible, and any appropriate metal can be selected from among such materials as Al, Cu, Ni, Ti, Zr, Ta and their alloys, etc. which is suitable for a particular equipment under question.
2) There being no diffusion from the base plate, the new process is suitable for lining of thin sheets-0.3-3.0 nun thick-for anticorrosive equipments.
3) No external heat being applied, the process is free of such problems as might develop from heat effects and intermediate alloys which are usual by-products in the conventional methods.
4) The required amount of explosives being much smaller than that of the conventional explosive welding for total surface cladding, the HABW process can be conducted in any factory compounds, and the use of stable and highly efficient explosives eliminates possible hazards which otherwise might be expected in the operations.
5) No large facilities nor skilled workers are necessary.
Required manufacturing cost can be reduced to a minimum by shortening of working time and elimina tion of after treatment, etc.
In this paper, the properties of explosively welded metal and manufacturing process of metal lined equipments are described, and the merits and applications of this new technique are discussed.View full abstractDownload PDF (17120K)
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