JOURNAL OF THE JAPAN WELDING SOCIETY
Online ISSN : 1883-7204
Print ISSN : 0021-4787
ISSN-L : 0021-4787
Volume 25, Issue 5
Displaying 1-15 of 15 articles from this issue
  • Summary
    H. Kihara
    1956 Volume 25 Issue 5 Pages 242-248
    Published: April 25, 1956
    Released on J-STAGE: December 10, 2009
    JOURNAL FREE ACCESS
    A development research of weldable high tensile manganese silicon structural steels with tensile strengths of 52 to 60 kg/mm2 and with a satisfactory notch toughness, were investigated by the 6th Reseach Committee of the Shipbuilding Research Association of Japan.
    Test steels were of nine production heats with the silicon contents varied from 0.1 to 0.6 percents to determine its optimum range. Eithteen kinds of tests ; namely, notch sensitivity tests, bead-bend tests, cracking tests, heat-treatment tests, and etc., were used to evaluate the weldability of test steels, and the correlations among these tests were also studied.
    From these studies, the composition limits and necessary properties to be adapted to weldable high tensile manganese silicon structural steels with thichnesses less than 20 mm were determined as follows ;
    (a) Chemical composition (Ladle analysis) :
    C ≤ 0.18% S ≤ 0.03%
    Mn ≤ 1.25% Cu ≤ 0.30%
    Si ≤ 0.55% Ni ≤ 0.25%
    P ≤ 0.03% Cr ≤ 0.10%
    (b) Mechanical properties :
    Yield strength ≥ 32 kg/mm2
    Tensile strength = 52 to 60 kg/mm2
    Elongation (8″) ≥ 20 %
    (c) Weldability tests :
    i) V-Charpy test
    Impact value (at 0°C) ≥ 3.5 kgm/cm2
    ii) Austrian test (Kommerell type, longitudinal bead bend test) Max. bend angle ( ≤20°C) ≥120°, and Bend angle at first crack (≤20°C) ≥ 60°Note- Austrian test is only required for plate thichness, 18 to 20 mm, inclusive.
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  • H. Kihara, H. Suzuki, H. Tamura
    1956 Volume 25 Issue 5 Pages 249-253
    Published: April 25, 1956
    Released on J-STAGE: December 10, 2009
    JOURNAL FREE ACCESS
    V-notch Charpy impact tests were performed of 30 ship steel plates which were rolled into 12 or 20mm in thickness from the top and bottom of nine production heats of weldable high strength manganesesilicon steels.
    The results of tests may be summarized as follows :
    (1) The yield ration was generally 65 percents. However, steels M3 and M6 showed higher ratio of 75% which was comparable to that of German HSB steel.
    (2) The notch toughness of test steels in as rolled condition was inferior to that of the current killed ship steels and approximately equal to that of rimmed steels. However, the notch toughness was improved remarkably by normalizing the test steels, and was then superior to that of killed steels.
    (3) The notch toughness was almost constant in a range, 0.3 to 0.6%, of silicon content.
    (4) The notch toughness of test steels was affected more remarkably by ferrite grain size of distribution of carbide, than by chemical composition.
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  • H. Kihara, H. Suzuki, H. Tamura
    1956 Volume 25 Issue 5 Pages 254-257
    Published: April 25, 1956
    Released on J-STAGE: December 10, 2009
    JOURNAL FREE ACCESS
    V-Charpy impact tests of high tensile manganese-silicon steels were performed over a range of temperature to investigate the effects of normalizing and silicon content on notch toughness.
    The conclusions may be summarized as follows :
    (1) The improvements in transition temperatures were considerable for silicon-aluminum killed steels, whereas only appreciable for silicon killed steels, K1B, K4B and K4T.
    (2) The values of 15 ft-lb transition temperature of silicon-aluminum killed steels were approximately independent of silicon content in a range of 0.30 to 0.60%.
    (3) The ductility of test steels, namely elongation and reduction of area in tensile test, was improved considerably by normalizing, whereas the yield point and tensile strength remained almost unaffected.
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  • M. Watanabe, Y. Ideguchi, T. Yamaguchi, H. Morii
    1956 Volume 25 Issue 5 Pages 257-260
    Published: April 25, 1956
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    Customary transition-temperature tests generally require too much material and are very laborious. In a previous report, one of the authors suggested a simple testing method to evaluate the notch toughness of materials, so-called simplified notch toughness test which was based upon the experimental results of structural mild steels. This method uses the properties that the values ofψ(ratio of true stress to strain at the maximum load in atensile test), ψ', ψ and ψ', which are described in the present paper, are constant within the temperature range of -80°C to 100°C and that the material having the smaller values of ψ, ψ', ψ or ψ' shows the lower transition temperature.
    The purpose of this report is studying the applicability of above mentioned simplified notch toughness test on various structural high tensile steels.
    The test results obtained were almost the same with that shown in the structural mild steels except, the temperature range in which the value of ψ or ψ' is constant as seen in Fig. 9 and Fig. 10. Moreover authors confirmed that ψ or ψ' obtained by room temperature test can be adopted as an index of the notch toughness of high tensile steels.
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  • M. Yoshiki, T. Kanazawa
    1956 Volume 25 Issue 5 Pages 260-264
    Published: April 25, 1956
    Released on J-STAGE: December 10, 2009
    JOURNAL FREE ACCESS
    Schnadt Test of Mn-Si high tensile steels, 12mm thickness, were executed.
    The following conclusions are obtained from the test results about the steels tested :
    (1) With the exception of K-1, Y-4 and M-8, the notch ductility of the tested steels are excellent. However, it is worth notice that the maximum absorbed energies of N-3 and N-6 are considerably lower than that of the other steels.
    (2) There are clear correlations between the transition temperatures obtained by Schnadt and Charpy Test. There are no significant superiority between these two tests.
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  • H. Kihara, T. Kusuda, K. Iida
    1956 Volume 25 Issue 5 Pages 264-266
    Published: April 25, 1956
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    For mild steels it has been recognized that the V-notch Charpy Impact value or the weld heat affected embrittled zone, 10 to 14mm apart from the center of welded bead, is decreased from the value of base metal. This paper deals mainly the experimental study on the similarly embrittled zone in high tensile Mn-Si steels. Standard V-notch Charpy test was employed to evaluate the notch toughness in the embrittled zone in eight high tensile Mn-Si steels, namely N3, N6, K1, K4, M3, M6, Y4 and Y6.
    The main conclusions are as follows:—
    1. Al inear relationship was found between the degree of embrittlement and the transition temperature of base metal, the higher the embrittlement, the higher the transition temperature.
    2. The degree of. embrittlement and the transition temperatures of the tested high tensile Mn-Si steels were lower than that of ordinary mild steels.
    3. The maximum temperature attained in the embrittled zone was lower than the Al transformation point.
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  • M. Yoshiki, T. Kanazawa
    1956 Volume 25 Issue 5 Pages 267-272
    Published: April 25, 1956
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    In order to investigate the notch sensitivity of Mn-Si high tensile steels, we have performed Lehigh Slow Bend Test using specimens with or without weld bead of FL-16 and B-17.
    Following results are obtained from the test :
    (1) Concerning the notch sensitivity, the tested high tensile steels are superior to the rimmed steels, and they are approximately on the same level or a little inferior to the killed steels.
    (2) There is a tendency that the fracture and ductility transition temperatures fall to a lower value as silicon content increases.
    (3) The ductility transition temperature of specimens having weld bead is considerably higher than that of without weld bead. However, as to the fracture transition temperature, there is no significant difference between these two kinds of speciment with and without weld bead.
    (4) Comparing the results of specimens with weld bead of FL-16 and B-17, there is no significant difference, but FL-16 weld bead shows a little better ductility than B-17 weld bead.
    (5) The notch ductility of thicker plates is generally inferior to that of the thinner plates.
    (6) There are no significant differences about the test pieces taken from the top or the bottom of ingot.
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  • H. Kihara, H. Tamura, S. Kaku
    1956 Volume 25 Issue 5 Pages 272-276
    Published: April 25, 1956
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    The bead-bend ductility of high-tensile manganese-silicon steels was investigated by Austrian test, Kommerell type longitudinal bead-bend test. Twelve steel plates of 20mm thickness were tested. As the basic criteria for evaluating steels, (a) the transition temperature at which the maximum bend angle reached at 90 degrees, (b) the maximum bend angle a-id (c) the bend angle at first crack at room temperature were used.
    The conclusions may be summarized as follows ;
    (1) Bead-bend ductility of test steels were remarkably inferior to that of the current mild ship steels. Therefore, in order to secure a satisfactory service performance of high tensile steels for welded structure, weldability test such as a bead bend ductility test is indispensable.
    (2) The maximum bend angle and the bend angle at first crack were closely related to the maximum hardnesses of heat-affected zone, and the both values decreased considerably as the maximum hardness etceeded about 350 VHN.
    (3) It was shown that normalizing before welding had not a pronounced effect on bead-bend ductility of test steels, but post-heating above 300°C improved the ductility significantly.
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  • M. Otani
    1956 Volume 25 Issue 5 Pages 277-281
    Published: April 25, 1956
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    Using slit type specimens, crack tests were performed to evaluate the cracking tendency of structural high tensile Mn-Si steels.
    It was found that as the maximum hardness in heat-affected zone (Hmax.) increased the cracking tendency of weld became marked. Cracks usually originated from the root of weld and grew along the heat-affected zone, then turning into the deposit. Hmax. seemed to increase proportionally with C and Mn contents but hardly increased with Si content for the range investigated. To prevent the weld crack C should be kept as low as possible; Mn below about 1.2%. There was not any indication that Si content promoted the craking tendency of weld. Of various types of electrodes applied for the test, the low hydrogen type proved to possess sufficient anti-cracking property.
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  • K. Masubuchi, Y. Ogura
    1956 Volume 25 Issue 5 Pages 282-285
    Published: April 25, 1956
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    The purpose of this test was to examine by means of the Lehigh restraint cracking test the effects of type of steel and electrode on crack susceptibility of high strength steel. The Lehigh restraint test is a butt-weld cracking test for comparing quantitatively the degree of restraint at which crack occurs. The results obtained in this test were as follows;
    1) The steel Y6B was most crack-insensitive of all steels tested.
    2) There seems to exist a linear relationship between the percentage of crack and the value of Tremlett's equivalent carbon, Ceq, which does not contain a term of silicon content.
    3) Among those electrodes used LH29 had greater crack susceptibility. The order of the other electrodes was as follows ; LB76, FL76, SL76, HTO52, the latter less cracking. Since this test was performed only once for each condition the effect of restraint on crack susceptibility was not obvious and therefore the degree of critical restraint could not be obtained. Consequently, the mean value of percentages of crack was used in the analysis of experimental results.
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  • K. Nakane, C. Yamagishi
    1956 Volume 25 Issue 5 Pages 286-291
    Published: April 25, 1956
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    The crack sensitity T-tests in accodrance with DIN 50129 and its modification were conducted on the tentative high tensile Mn-Si steels using various types of electrode. Comparisons were made among the test plates and electrodes and they were graded in the order of weldability.
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  • H. Kihara, H. Suzuki, H. Tamura
    1956 Volume 25 Issue 5 Pages 292-296
    Published: April 25, 1956
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    The effects of ferrite grain sizes and microstructures after various heat treatments on the V-Charpy transition temperatures were investigated with two high tensile Mn-Si steels, of approximately the same chemical comporition, but the one aluminum treated and the other not-treated.
    The results obtained are summarized as follows ;
    (1) The austenitic grain-coarsening temperature of the Al treated steel N3B was considerably higher than that of Al non-treated steel K1B.
    (2) A close relationship was found between the ferrite and the austenite grain sizes after various heat treatments of test steels.
    (3) Generally, the transition temperature increased with increasing the austenitizing temperature and with lowering cooling rate.
    (4) The greatest difference in transition temperatures between these steels occured after heat treatment at about 950°C at which the difference of austenitic grain sizes was the most significant.
    (5) A linear relationship exsisted clearly between the V-Charpy transition temperature and the ferrite grain size.
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  • M. Otani
    1956 Volume 25 Issue 5 Pages 296-299
    Published: April 25, 1956
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    Tensile tests were made on welded butt joints with internal defects (Fig.1). Four charges of structural high tension steels and one mild steel, 20 mm thick, combined with two different types of electrodes were used for the test.
    In accordance with the result reported for the mild steel plate, 23mm thick, it was proved that the fracture transition temperature of welded joint (Trs) in this experiment could also be predicted by the similar equation,
    TrS=2/3(0.60TrS(B)+0.45TrS(D))-52 (°C)
    where TrS(B) and TrS(D) are the 50% shear transition temperatures of base and deposited metals by V-Charpy impact test.
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  • H. Kihara, H. Suzuki, N. Ogura
    1956 Volume 25 Issue 5 Pages 300-303
    Published: April 25, 1956
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    The effects of impact loading on the transition temperatures of notched or unnotched bead bend specimens were investigated with five high tensile steels and the following conclusions were obtained:
    1) With unnotched bead bend specimens the absorbed energies were increased and the transition temperatures were decreased by impact loading.
    2) The energy transition temperatures of notched bend specimens of base metals were increased considerably by impact loading, and these specimens showed completely brittle fractures in the temperature range of room temperature to -70°C.
    3) The rating of notch toughness of the steels by notched bend impact test was remarkably different from that by V-Charpy impact test.
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  • Y. Ando
    1956 Volume 25 Issue 5 Pages 304-306
    Published: April 25, 1956
    Released on J-STAGE: June 12, 2009
    JOURNAL FREE ACCESS
    Welded joint tests were performed for 8 charges of tentative HT52 high tensile steels, and the results may be summarized as follows:
    1. 100% joint efficiency could be obtained for manualy weld with low-hydrogen electrodes, and also for submerged-arc welded joints.
    2. Results of bend tests and longitudinal tensile tests showed sufficient ductility of welds.
    3. Results of alternative bending fatigue tests were also satisfactory.
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