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Volume 35, Issue 11
Displaying 1-9 of 9 articles from this issue
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Mitsuo Hasegawa1966 Volume 35 Issue 11 Pages 1057-1068
Published: November 25, 1966
Released on J-STAGE: August 05, 2011
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Tetsugoro Muramoto1966 Volume 35 Issue 11 Pages 1067-1078
Published: November 25, 1966
Released on J-STAGE: August 05, 2011
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Mainly on Calculation Formulae Proposed by I.I.W.Shozaburo Ohta1966 Volume 35 Issue 11 Pages 1079-1094
Published: November 25, 1966
Released on J-STAGE: August 05, 2011
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On the welding conditions and its effects on Welding mechanismMinoru Okada, Hiroshi Maruo, Keizo Nanba1966 Volume 35 Issue 11 Pages 1095-1102
Published: November 25, 1966
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSRecently, plasma process has been applied to such industrial uses as cutting and spraying. Arc plasma is constricted by the gas flow and/or metallic wall of nozzle in a plasma process. The temperature and the thermal energy intensity of the constricted arc plasma are much higher than those of ordinary open arc. In the cutting and welding applications, it will be expected that the plasma stream has a property of line heat source similar to the one as observed in Electrlon Beam Welding.
In this report the experimental results on the plasma welding of stainless steel plate are described briefly. The electric capacity of plasma welding torch used in these experiments is about 8 KW. The plasma welding is capable of producing a narrow and deep weld bead by the action of "Key Hole". And a sound weld is obtained by one pass of torch even for a 15 mm thick plate. With the above welding energy source, optimum welding conditions are established for various thickness of plate. Welding speed in plasma process is much higher than that in TIG welding and others at the same welding energy.
Various tests on the microstructure, mechanical property and the deformation of weld specimen are carried out with satisfactory results.
It was confirmed that the formation of key hole in crater of bead had much influence upon the welding results. When the key hole is not formed, porosity is contained in most weld beads. The formation of key hole is sensitive to the travelling speed.View full abstractDownload PDF (7072K) -
Kohei Ando, Takashi Nakamura, Kimiyuki Nishiguchi, Masanobu Hamasaki1966 Volume 35 Issue 11 Pages 1103-1120
Published: November 25, 1966
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSThe maximum temperature rise in electrode tip is estimated from the measured heat input to the electrode during one spot welding. It reaches as high as about 700°C for ordinary spot welding conditions of steel plates of 0.8-3.2 mm thickness.
For calculation the electrode cross section is assumed constant along the electrode length, and the effect of wave form of heat flow from the tip is investigated. Q in Table 1 is the measured heat input to each side of the electrode per one welding under the conditions shown in the table. θ2 in the table shows the calculated results using the equation (9) under the following assumption, i.e. the heat flow wave form is taken as Fig. 11(a), heat flow time TH is assumed as equal to current flow time T0 shown in the table, the cross section of the electrode is taken as S2 corresponding to the root diameter of the electrode.
Fig.14 shows the temperature distribution curves along the length when a constant heat H=1000 cal/cm2 sec flows in from the electrode tip for the duration TH=0.25, 0.5, 1.0, 1.5sec. Curves A-D show the temperature rise when the distance x0 of cooling end from the tip is infinity and A, B'-E' for x0=1 cm. For the calculation of the effect of cooling water, it is assumed that equation (33) holds, according to the model shown in Fig. 13 (h is taken as 1 for Fig. 14 and 18).
Heat flow time TH is divided into two parts as shown in Fig.17 and the temperature at the moment C is calculated as the sum of the parts. Temperature due to the part AB is calculated using equation (49), T1 being time constant defined as in equation (43) and the period of BC is chosen far longer than time constant T2.
It is easily shown that the magnitude of temperature fluctuation at a point I cm distant from the tip is negligible when intermittent heat input cycle is less than 1 sec/spot and we see that the cooling effect of cooling water is only effective to reduce the average temperature rise in the electrode under intermittent welding.
Table 3 shows the temperature rise at the tip for cyclic heat flow from the tip for various combinations of x0, h, TH and Tw (i.e. cyclic period). The value shows the temperature at the moment C in Fig. 19 for H=1000 cal/cm2 sec.
Fig.2, 4 shows the oscillogram of the temperature rise at 2 mm distant from the tip (Fig.1). Electrode pressure is also shown in Fig.2.View full abstractDownload PDF (4947K) -
Kohei Ando1966 Volume 35 Issue 11 Pages 1121
Published: November 25, 1966
Released on J-STAGE: August 05, 2011
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Effect of additional elements on Weld-crack susceptibilityYoshihiko Sugiyama, Toshiyasu Fukui1966 Volume 35 Issue 11 Pages 1122-1129
Published: November 25, 1966
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSA study has been made of the effect of additional elements on the weld-crack susceptibility of Al-4.5% Zn-1.5% Mg and Al-5.0% Zn-2.0% Mg alloys.
Weld-crack susceptibility was evaluated by MIG-spot cracking and Fish-bone cracking tests. The former was carried out with 5356 filler and the latter was carried out without filler, with Al-Zn-Mg filler, 5356 filler or parent metal filler.
The results were as follows:
1). The addition of zirconium to parent metal has a remarkable effect for reducing weld-crack susceptibility.
2). Neither titanium nor boron addition has any appreciable effect, though these elements serve as well to refine the structure of the weld metal as zirconium does. Titanium however, has some effect for reducing weld-crack susceptibility, only when 5356 filler is used.
3). None of other additional elements such as copper, silver, chromium and manganese was found to be effective for reducing weld-crack susceptibility.
4). Weld-crack susceptibility depends not only on the grain size but also on the volume and form of the liquid film, which is formed with boundary segregation of eutectic composition far from equilibrium.View full abstractDownload PDF (5689K) -
Effect of AlN on the Continuous-Cooling Transformation of Carbon SteelMinoru Okada, Shigeo Shin, Yoshikuni Nakao, Hiroshi Misawa1966 Volume 35 Issue 11 Pages 1130-1138
Published: November 25, 1966
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSIn the previous work, it was concluded that the microstructures of A1N bearing low carbon steel (AN-1) were almost similar to those of aluminum killed low carbon steel (AN-IC) after various weld thermal cycles (max. heating temp.: 1350°C).
AN-1 and AN-1C being affected by various weld thermal cycles (max. heating temp.: 1150°C), the microstructures of AN-1 were ferrite+pearlite, but those of AN-1 C were mainly intermediate.
These results indicate that AIN will probably affect the transformation process of carbon steel.
In this study, continuous cooling transformation diagrams of AN-1 and AN-1C were made using a particular equipment applying magnetic analysis and the effect of A1N on the continuous cooling transformation of carbon steel was investigated.
Also the effect of A1N on the Ar3 transformation of carbon steel was researched.
The results obtained in this study are summarized as follows.:
(1) AN-1 and AN-IC being rapidly heated to 1350°C and cooled under various conditions, the difference between C.C.T. diagram of AN-1 and that of AN-1C was little.
(2) AN-I and AN-IC being rapidly heated to 1200°C and cooled under various conditions, the critical cooling times of AN-1 to nucleate intermediate structure, ferrite and pearlite were shorter than those of AN-IC and respectively 0.42, 0.86 and 3 sec.
(3) After heattreated at 1350°C for 10. min, quenched to 730°C and held at 730°C, the Ar3 transformation velocity of AN-I was almost the same as that of AN-IC.
(4) After heat-treated at 1200°C for 10 min, quenched to 730°C and held at 730°C, the Ar3 transformation velocity of AN-l was larger than that of AN-IC for about 9 sec after the beginning of Ar3 transformation.
Especially, the Ar3 transformation velocity of AN-1 was 2-2.5 times larger than that of AN-1C for several initial seconds after the beginning of Ar3 teransformation.View full abstractDownload PDF (8141K) -
Katao Miyano, Yuzuru Shindo1966 Volume 35 Issue 11 Pages 1139-1145
Published: November 25, 1966
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSEffect of hot forming process such as hot bending, line heating and spot heating on the mechanical properties of double normalized and tempered 9% Ni steel was studied by examining both tensile properties and impact behaviours.
The results are summarized as follows:
1. Most suitable heating temperature in hot bending was 820°C to 950°C, and normalizing at 900°C, normalizing at 790°C or normalizing at 790°C, and tempering at 570°C followed by air cooling were needed to obtain good notch toughness after forming.
2. The examinations of microstructures showed that good notch toughness was correlated with solution increase, spherical degree of carbides.
3. Line heating tended to harden especially the heating surface, and greatly reduce the notcc toughness. However the notch toughness reduction at the mid-wall and the bottom surface (plate thickness was 13.5 mm) was slight in the case when water spray cooling from maximum heaating temperature of 550°C to 900°C was applied.
4. Spot heating must be avoided, for local shrinkage makes the notch toughness scatter and reduce the toughness value itself.View full abstractDownload PDF (3682K)
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