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Volume 24, Issue 11
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I. Ueda1955 Volume 24 Issue 11 Pages 421-423
Published: 1955
Released on J-STAGE: December 10, 2009
JOURNAL FREE ACCESSThis paper reports the effects of the acetylene pressure in the gas cutting. In this, experiments, acetylene pressure has been investigated as a factor affecting the rise of cutting speed in the gas cutting.
The results were as follows:
(1) Acetylene pressure rises the cutting speed and the relation between acetylene pressure and cutting speed is proportional.
(2) When higher acetylene pressure, is used its consumption is lowered at given thickness.
(3) Heat affected zone versus cutting speed is proportional.View full abstractDownload PDF (3289K) -
I. Oi, S. Imai1955 Volume 24 Issue 11 Pages 423-430
Published: 1955
Released on J-STAGE: December 10, 2009
JOURNAL FREE ACCESSEarlier the authors reported the results of bending test on the rails welded by gas pressure method. The present report deals with elaborate examinations subsequently carried out.
The flash-butt process has been widely practised on the National Railways with nearly satisfactory results; some comparison of results is made here between this process and gas pressure method. Heat treatment after pressure welding is not also made in the tests reported.
First, hardness, structure etc have been investigated of important spots in the tread of rail top or the interior.
The results show that weldes as such are perfect ; especially in the pressure welds, there are no decarburized layer observed. But picric etch has revealed that actual grain sizes are considerably coarse, particularly at the base.
Next, tension, charpy, Matsumura's repeated impact and Schenk type repeated bending specimens were take test the mechanical strength of each part. In the tension test, all specimens except one broke in the mother part, with tensile strength proving to be higher than that of base metal and to be distri. buted generally even for each area. The impact value of base metal was found unexpectedly low ; individual comparison showed that pressure welds had had sometimes higher impact values, but in the aggregate, more often had lower values. Repeated impact value for the tread of rail top was in general satisfactory, i.e. as high as that of base metal; but at the base it fell to 64.7% of that of the latter.
In the Schenk test, 15.5% lower than of the top of pressure welded rail gave a fatigue limit (45 kg/mm2) 15.5% less than that of mother metal against 28.5% less for both ends of the base and 22.2% less for the centre of the base.
Lastly, the full size specimenss of pressure welded rail with stood a rotating fatigue test under working loads up to 2, 000, 000 loadings without starting any crack and now tliey are being put to the field test.View full abstractDownload PDF (12469K) -
On the Case of Low Manganese SteelH. Sekiguchi, M. Inagaki, A. Arakawa1955 Volume 24 Issue 11 Pages 430-435
Published: 1955
Released on J-STAGE: December 10, 2009
JOURNAL FREE ACCESSWhen low manganese steel bars (C0.20%, Mn1.56%) are flash-butt-welded, the decrease of carbon and manganese in the weld metal are remarkable. And the heat affecled zone shows coarse widmanstätten structure containing troostite. This part must be postheated at just below A1 transformation point in order to change the troostite to sorbite, and postheated at about 800°C in order to change the widmanstätten structure to fine grain structure. Accordingly, if the both change are desired, it will be suitable that these parts are postheated at about 750°C.
In the case of postheating with a flash-butt-welder, the postheating at about 850°C is suitable. Holding time at postheating temperature is sufficient with one second.View full abstractDownload PDF (4440K) -
T. Naka1955 Volume 24 Issue 11 Pages 435-439
Published: 1955
Released on J-STAGE: June 12, 2009
JOURNAL FREE ACCESSIn this short report the author describes the anisotropic mechanical properties of rolled steel plates of 25 mm thickness and 80 mm thickness. Yielding points, tensile strength, elongation percentages, reductions of areas, bending angles and impact values are mesured by them in the directions of rolling (X), transverse (Y) and depth (Z). It should be noted that the ductility properties and impact values are showing inferiority in Z directions even in the cases of showing superiority in the other directions.
These tendencies are seemed to have rather close relations to their rolling methods than their kinds of ingots.View full abstractDownload PDF (409K) -
M. Otani1955 Volume 24 Issue 11 Pages 440-446
Published: 1955
Released on J-STAGE: June 12, 2009
JOURNAL FREE ACCESSDouble blow impact tests were performed on V-noched Charpy specimens of deposited steels at temperatures, -70°C to 80°C, to divide the total energy absorbed by the standard impact test (Wc) into the energy for crack initiation (Wi) and the one for crack propagation (WD). Two ilmenite type electrodes (No. 1 and No. 4) and a low hydrogen type one (No. 9A) were used for the tests. The same experimental procedure for the rolled steel plat was adopted as previously mentioned in the author's report. The Figs. 2-4 show the test results.
From these figures, both the Wi-and the Wp-temperature curves were determined (Figs.5-7). The Wi curve of No. 9A was much higher in its maximum value and located at exceedingly lower temperature side than no. 1; on the other hand, Wp curves of both deposits showed no remarkable difference. By No. 4 deposit, less deoxidized than No. 1, either curve of Wi and Wp was located at higher temperature side than No. 1.
Those characteristics of energy curves were discussed in relation to the transition temperatures of welded joints investigated by the author.View full abstractDownload PDF (515K) -
Some Investigations for the Effect of Working Processes on High Tensile Steels Commercially ProducedT. Yoshida, W. Matsunaga, K. Terai, T. Murase1955 Volume 24 Issue 11 Pages 446-453
Published: 1955
Released on J-STAGE: June 12, 2009
JOURNAL FREE ACCESSThis paper includes, as its object, the study on the effect of various fabrication operations such as both cold and hot forming, water-quenching and various cutting processes on the notch sensitivity of structural high tensile steels. Tests were made as follows ;
V-notch charpy impact specimens were taken parallel to rolling direction from the strained parts of both cold and hot bending of various radii, and heating centre or embrittled zone of water-quenched parts, then tested over a range of temperature from-65°C to +90°C. To investigate the effect of cutting operations to the notch toughness of the steel, U-notch tear specimens were used. The U-notch of the specimen was prepared by machining, flame-cutting or shearing and tests were made over a range of temperature from -100°C to +70°C The same tests as above-mentioned also were made of mild steel plate and its results were compared with those of high tensile steels.
As a result it has been cocluded that
(1) Cold forming is unfavourable as it reduces ductility of steel when proportion of bending radius vs plate thickness below 3.5 is obtained.
(2) It is easy to intinate crack at embrittled zone of periphery of water-quenched part for HTS steel because of its hardenability
(3) Shearing process reduces ductility of steel remarkably while flame-cut edges show sufficient ductile behaviour.View full abstractDownload PDF (4944K) -
[in Japanese]1955 Volume 24 Issue 11 Pages 454-458
Published: 1955
Released on J-STAGE: June 12, 2009
JOURNAL FREE ACCESSDownload PDF (5793K) -
[in Japanese]1955 Volume 24 Issue 11 Pages 459-464
Published: 1955
Released on J-STAGE: June 12, 2009
JOURNAL FREE ACCESSDownload PDF (13737K) -
[in Japanese], [in Japanese], [in Japanese]1955 Volume 24 Issue 11 Pages 465-470
Published: 1955
Released on J-STAGE: June 12, 2009
JOURNAL FREE ACCESSDownload PDF (548K) -
1955 Volume 24 Issue 11 Pages 470
Published: 1955
Released on J-STAGE: June 12, 2009
JOURNAL FREE ACCESSDownload PDF (17K)
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