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Volume 34, Issue 9
Displaying 1-13 of 13 articles from this issue
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Alexis Neumann1965 Volume 34 Issue 9 Pages 861-867
Published: September 25, 1965
Released on J-STAGE: August 05, 2011
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Werner Giled1965 Volume 34 Issue 9 Pages 868-874
Published: September 25, 1965
Released on J-STAGE: August 05, 2011
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A Study of Root Cracking in High Strengh Steel Welds (Report 6)Michio Inagaki, Harumasa Nakamura, Haruyoshi Suzuki1965 Volume 34 Issue 9 Pages 875-888
Published: September 25, 1965
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSEffects of microstrure on root cracking of high strength steel welds were discussed in this report, mainly with the use of SH-CCT diagrams of test steels. Critical hardness values for root cracking were also discussed.
The main conclusions obtained in this study are as follows :
(1) A safety cooling process to prevent root cracking in HAZ should be chosen so that the ferrite and intermediate structure may appear more than about 40% for HT 60, intermediate structure more than about 25% for HT 70, and more than about 10% for HT 80 steels, respectively, when a joint of severe restraint is welded with a low hydrogen type electrode.
(2) For a weld metal, it is necessary to prevent root cracking in a severe restraint joint that the ferrite and intermediate structure precipitate more than in HAZ.
(3) A root crack in HAZ or weld metal is a mixed fracture of transcrystalline and intercrystalline types.
(4) There was found no relationship between root cracking tendencies and Mf temperatures.
(5) Retained austenite in HAZ was decomposed with the lapse of time above 250°C, but did not affect the root cracking phenomena.
(6) Critical hardness, above which a root crack will surely occur in a joint of severe restraint, were found to be as follows :
270 VHN (1 kg) for HAZ of mild steel weldment
365 VHN (1 kg) for HAZ of HT 50 weldment
400 VHN (1 kg) for HAZ of HT 60 weldment
405 VHN (1 kg) for HAZ of HT 70 weldment
415 VHN (1 kg) for HAZ of HT 80 weldment
290 VHN (1 kg) for weld metal of HT 50 and HT 60 weldments
330 VHN (1 kg) for weld metal of HT 70 and HT 80 weldmentsView full abstractDownload PDF (9700K) -
The Electrode Movement as the Pneumatic Machine System of the Spot Welding MachineTsugihiko Satoh, Jyoichi Katayama1965 Volume 34 Issue 9 Pages 889-894
Published: September 25, 1965
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSIn this report, first we analyze experimentally the electrode movement as the pneumatic machine system of the spot welding machine using the high speed motion camera, and make clear the relations of the electrode movement with the electrode stroke, the pressures of the upper and lower air chambers and time.
Next, it is proved that the damping oscillation of the upper and lower electrodes begins from the instant of the impact of upper electrode with the lower part.
Then, we study the effects of this impact on the surface properties of the weld piece, for example, the contact area, and contact resistance between the weld pieces.
Putting the above facts together, knowledge to select the squeeze time under various conditions in the spot welding is obtained.View full abstractDownload PDF (350K) -
Properties of Weld Metal for 70, 80kg/mm2 High Tensile Strength SteelToshikage Ikkai, Fuminori Watanabe1965 Volume 34 Issue 9 Pages 895-902
Published: September 25, 1965
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSIn the previous reports, characteristics of bonded flux and various properties of weld metal which was deposited by submerged arc welding with expermentally manufactured bonded flux for stainless steel, low carbon steel and high tension steel up to 60 kg/mm2 was described. This time, bonded fluxes was manufactured for the purpose of automatic welding on steels having 80 kg/mm2, that is, super high tension steels which have been required for the manufacturing of chemical phants equipment, spherical thnks and rail cars due to rapid progress of various industries. Primarily tensile strength and low temperature impact properties of weld metal was obtained by using this flux. The summary of the results of this invesigation is the following.
(1) Bonded flux for superior high tension steel is made of fundamental composition of bonded flux H-550 for low carbon steel. Its operational property is good and formation of bubbles is not observed in weld beads. Certain irregularities are observed, however, on beads' surface due to deposition of added deoxydizer and alloying elements.
(2) In welding of superior high tension steel of 70 kg/mm2 class, the combinations of flux and wire S-7 C+H-555 and #56+H-700 gives weld metal of good tensile strength and tonghness, and welding of superior high tension steel of 80 kg/mm2 class, the combinations of S-7 C+H-803 and #56+H-600 gives good result.
(3) The maximam hardness of heat affedted zone by welding for 2 H ultra steel of 80 kg/mm2 class becomes about Hv : 350 in as welded, condition and by stress reliving annealing yf 600°C 1 h, the hardness decreases some what. Also 7 QC of 70 kg/mm2 class has the maximum hardness of about Hv : 300.
(4) According to Fisco cracking test result, crack occurs 100% for welding at ordinary temperature even for any combination. Therefore, in welding, preheating to 250°C-300°C is neccessary.
(5) Welded jonts of 80 kg/mm2 class steel with conbination of 056+H-800 showed fatigue strength of about 48 kg/mm2 against repeated tension load of 2 × 106.View full abstractDownload PDF (2989K) -
Some Looks of its Creep Rupture with High Temperature Properties of Synthetic HAZ SpecimensIsao Okane1965 Volume 34 Issue 9 Pages 903-910
Published: September 25, 1965
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSThe creep rupture configuration of large welded specimens, having the shape as welded, was very different from that of conventional small welded specimens, cut off from the weld joint. The initiation of crack in rupture occurred at the toe of weld metal and the intersection of the bonds of both side weld metal. The crack propergated along the grain boundary of austenite of bond in the heat-affected zone of base metal.
The mechanism of creep rupture for large welded specimens was investigated with results of high temperature tensile test and creep rupture test at 500°C for synthetic HAZ specimens. The specimens were synthesized the coarse grain part near bond (max. heating temperature 1, 350°C), the fine grain part (max. heating temperature 900°C) and the intermediate part (max. heating temperature 1, 100°C) in the heat-affected zone of base metal.
By results of tests, high temperature tensile and creep rupture properties of the coarse grain part near bond were inferior to the other parts and the rupture occurred in austenite boundary. Especially, the absorbed energy to rupture of the coarse grain part near bond was smaller than that of the other parts above 400°C. Consequently, the creep rupture of large welded specimens may be occurred along the grain boundary of austenite of bond in the heat-affected zone of base metal.View full abstractDownload PDF (7386K) -
Shozaburo Ohta, Mitsunori Nakata, Shinpei Iizuka1965 Volume 34 Issue 9 Pages 911-922
Published: September 25, 1965
Released on J-STAGE: August 05, 2011
JOURNAL FREE ACCESSConcerning the method of bend test for butt welded joint, the significance of the method of test and the influence of bend conditions on the test results were investigated.
The necessary conditions of the method of bend test for butt welded joint are thought to be the following four : (1) frirness : to be able to judge test results with fairness, (2) reasonableness : to be able to give bend elongations as uniformly as possible to both weld metal and base metal, in the test of joint, (3) severity : to be able to give a considerable magnitude of maximum local bend elongation, and (4) simplicity : to be able to perform a test simply and easily.
Conditions (1), (2) and (3) tend to conflict with one another. By synthetic estimation, a guided bend test and a roller bend test with a large radius loading-pin are tolerable, and a free bend test and a roller bend test with a small radius loading-pin are thought to be somewhat inadequate as bend test. But if selectively applied according to the characteristics and object of test, each of these bend tests will have its own significance.
With an increasing strength of base metal (when the strength of weld metal nearly equals to the one of base metal), the severity tends to rapidly increase, therefore in order to keep the severity constant in the case of a roller bend test, the loading-pin radius must be increased. Similarly, in the case of a guided bend test, it seems to be necessary to change the size of the guided bend test jig.
After all, the significance of the method of bend test for butt welded joint is thought to be confined to the under-cut (simple) test. As the above-mentioned characteristics fluctuate on account of the variation of shape and size of test specimen (plate thickness, width and shape and size of weld metal etc.) etc., it is considered important to inspect the characteristics of bend test method before a special bend test is performed.View full abstractDownload PDF (2532K) -
1965 Volume 34 Issue 9 Pages 944-960
Published: September 25, 1965
Released on J-STAGE: August 05, 2011
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1965 Volume 34 Issue 9 Pages 961-977
Published: September 25, 1965
Released on J-STAGE: August 05, 2011
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1965 Volume 34 Issue 9 Pages 978-994
Published: September 25, 1965
Released on J-STAGE: August 05, 2011
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1965 Volume 34 Issue 9 Pages 995-1008
Published: September 25, 1965
Released on J-STAGE: August 05, 2011
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1965 Volume 34 Issue 9 Pages 1009-1022
Published: September 25, 1965
Released on J-STAGE: August 05, 2011
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1965 Volume 34 Issue 9 Pages 1023-1035
Published: September 25, 1965
Released on J-STAGE: August 05, 2011
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