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51 巻, 12 号
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稲垣 道夫1982 年 51 巻 12 号 p. 973-980
発行日: 1982/12/05
公開日: 2011/08/05
ジャーナル フリーPDF形式でダウンロード (606K) -
桑名 武, 粉川 博之1982 年 51 巻 12 号 p. 981-988
発行日: 1982/12/05
公開日: 2011/08/05
ジャーナル フリーThe micro-structure distribution of SUS304L stainless steel heat affected zone was investigated by transmission electron microscopy. The results are as follows:
(1) Small ferrite phases were observed at sub-boundaries near the fusion boundary in the coarse grained region by transmission electron microscopy, which were not recognized by optical microscopy.
(2) The degree of recovery in the dislocation structure became lower in the heat affected zone with the distance from the fusion boundary.
(3) No grain boundary precipitations were observed in the grain boundary etched region by transmission electron microscopy.
(4) The Vickers hardness distribution can be explained by the distribution of grain size and dislocation density.抄録全体を表示PDF形式でダウンロード (9941K) -
24Cr-24Ni-1.5Nb系鉄基耐熱合金の溶接割れに関する研究(第2報)中尾 嘉邦, 大重 広明, 古賀 信次, 西原 久尅, 杉谷 純一1982 年 51 巻 12 号 p. 989-995
発行日: 1982/12/05
公開日: 2011/08/05
ジャーナル フリーIn this study, the effect of Nb/C on the sensitivity of liquation cracking of 24Cr-24Ni-1.5Nb Fe-base heat resisting alloy (IN-519) was researched at first. Then, metallurgical inspections on various phases at grain boundaries were conducted. Solidification phenomena of this alloy were also examined. The main results obtained in this experiment are as follows;
1) The sensitivity of liquation cracking of this alloy becomes minimum when the value of Nb/C is about 1.0. Its sensitivity increases in the case of Nb/C value decreasing less than about 1.0 or increasing more than about 1.0. When Nb/C value decreases less than about 1.0, Cr carbide-r solid solution eutectics are formed at grain boundaries besides NbC-r solid solution eutectics. As the solidification temperature of Cr carbide-r solid solution eutectic is lower compared with that of NbC-r solid solution eutectic, the solidification cracking sensitivity increases. When Nb/C value increases more than about 1.0, Laves phase-r solid solution eutectics of which solidification temperatures are lower than those of NbC eutectics, are formed at grain boundaries. So, the sensitivity of liquation cracking of this alloy increases again.
2) To improve the resistivity to liquation cracking of this alloy, increasing Nb content and decreasing C content are very effective.抄録全体を表示PDF形式でダウンロード (2276K) -
衝撃試験破面に対する検討迎 静雄, 加藤 光昭, 西尾 一政, 崔 相旭1982 年 51 巻 12 号 p. 996-1002
発行日: 1982/12/05
公開日: 2011/08/05
ジャーナル フリーIt is necessary to know the distributions of plastic strain in the materials and also the features on fracture for analyzing the fracture mechanism. In this investigation, fracture surfaces after impact test was analyzed using X-ray micro-diffractometer. The material used was Al-killed steel. Plastic strains on the fracture surfaces were evaluated using the integral breadth of X-ray diffraction intensity curves. Plastic strain was large near the notch root and had minimum at a position 2-3 mm away from the notch root. Thereafter, the plastic strain increased as the distance from the notch root increased. The estimated energy using plastic strain thus obtained corresponded approximately to the impact energy.抄録全体を表示PDF形式でダウンロード (3444K) -
平岡 裕, 入江 宏定, 岡田 雅年, 渡辺 亮治1982 年 51 巻 12 号 p. 1002-1008
発行日: 1982/12/05
公開日: 2011/08/05
ジャーナル フリーThe purpose of this study is to investigate the effects of macrostructure change of the weld joint on the ductility of electron-beam-welded molybdenum sheet. The material used was electron-beam-melted molybdenum. Beam oscillation was applied in order to change the unfavourable structure of the joint, particularly even flat and straight interfaces at the center of the weld metal or at the bond of weld. The ductility of the weldment was determined by tensile tests at -70°C and 20°C. Fracture mode and location of crack initiation and propagation were examined by a scanning electron microscopy.
The results were summarized as follows:
1) Fracture strength at -70°C of the weldment was increased by using beam oscillation.
2) Strength and elongation at 20°C of the weldment were also increased by using beam oscillation. 3) Origin of fracture was located to be mainly at the grain boundaries on the bead surface at -70°C, whilst crack was initiated mainly from the grain boundaries in bulk at 20°C.
4) Crack was propagated only along the center of the weld metal or the bond of weld without beam oscillation. On the other hand, the crack was propagated not only along these weak interfaces but also through other areas with beam oscillation.抄録全体を表示PDF形式でダウンロード (3335K) -
Ni合金多層溶接金属部のビード下ミクロ割れの特性森重 徳男, 岡林 久喜1982 年 51 巻 12 号 p. 1008-1014
発行日: 1982/12/05
公開日: 2011/08/05
ジャーナル フリーMultirun welds of 25Cr-20Ni steel, 18Cr-lONi-Nb steel and Inconel are susceptible to microcrackirg (under-bead microcracking in weld metal). in underlying weld runs. To study the mechanism of this under-bead microcracking, Inconel multirun weld deposits, were made in the form of pads on mild steel plate, using widely varying heat inputs and interpass temperature. The results obtained in the present study are as follows:
1. Microcracks were observed in the previous-layer weld metal reheated by the heat of subsequent bead, when welds were made on the mild steel dipped partially in water of about 20°C in order to lower interpass temperature.
2. No microcrack, however, was found when preheating was applied at about 150°C.
3. The, degree of microcracking increased with decreasing heat input, particularly with increasing weld-ing speed.
4. Metallographic examination and weld thermal stress analysis were carried out And the mechanism of under-bead microcracking was discussed. As a result, it is concluded that (1) the under-bead micro-cracking occurs in the heating process of the heat cycle due to subsequent bead, and (2) precipitous thermal gradient causes high thermal strain and induces microcracking.抄録全体を表示PDF形式でダウンロード (4429K) -
西谷 弘信, 田中 洋征, 別所 諄之1982 年 51 巻 12 号 p. 1015-1020
発行日: 1982/12/05
公開日: 2011/08/05
ジャーナル フリーZero-to-tension axial fatigue tests were made on two types of 0.18C steel specimens. One is a circumferentialty notched specimen and the other is a simulated butt welded specimen with a backing strip machined from the base metal.
First, axial fatigue tests were carried out on the notched specimens, in order to obtain the root radius, ρ0, of a notch at the branch point (the critical point where a non-propagating crack appears) and the relation between the critical maximum stress for crack initiation and the stress gradient.
By using the results, a method for predicting the fatigue limits of butt welded joints was presented. The fatigue limits of the simulated butt welded specimens were in good agreement with-the calculated values based on the proposed method.抄録全体を表示PDF形式でダウンロード (1411K) -
財前 孝, 青木 司郎, 鈴木 克巳, 樺沢 弥1982 年 51 巻 12 号 p. 1020-1027
発行日: 1982/12/05
公開日: 2011/08/05
ジャーナル フリーThe creep and tensile properties of 308 type stainless steel weld metals were studied and following results are obtained.
(1) The amount of scatter in measured value of the creep rupture strength at 550°C, 300hr is about 10 kgf/mm2, and that of tensile strength at elevated temperature up to 700°C is about 15 kgf/mm2 for the standardized 308 type stainless steel weld metals.
(2) As the quantity of N increases the creep rupture strength, the relation between creep rupture strength σc and N content CN can be expressed as follows, σc=A+B log CN
where A is the constant varing witb composition, welding method, coefficient B indicates the mag- nitude of the effect of N for the creep rupture strength. The same statement is true on the relation between tensile strength and N content.
(3) The addition of about 0.1% of V strengthens the effect of N on creep rupture strength.
(4) N decreases the creep rupture elongation. The addition of about 0.1 %. of V controls the effect of N on the creep rupture elongation.
(5) The tensile rupture elongation decreases at temperature range between 20°C and 500°C, and the elongation increases at temperature above 550°C with increasing temperature. The addition of N above 0.078%, controls the decrease of creep rupture elongation at temperature range between 20°C and 500°C, and decrease the elongation above 600°C, for the 308 type stainless steel weld metals.
(6) The quantity of Cr in δ ferrite is 3 % more than that of austenite, and the quantity of Ni in the δ ferrite is 3% less than that of austenite for the 308 weld metal containing 0.01 % N. In the case of the steel containing 0.253 % N, the quantity of Cr in 6 ferrite is 9 % more than that of austenite, and the quantity of Ni in the δ ferrite is 2% less than that of the austenite. The amount of precipitate formed in δ ferrite of the latter steel is less than that in the former δ ferrite.抄録全体を表示PDF形式でダウンロード (2106K) -
電気抵抗測定による拡散溶接の接合初期過程の基礎的研究(第2報)圓城 敏男, 池内 建二, 秋川 尚史1982 年 51 巻 12 号 p. 1028-1035
発行日: 1982/12/05
公開日: 2011/08/05
ジャーナル フリーThe early process of diffusion welding of aluminum, titanium and copper whose faying surfaces have been finished by polishing with emery papers of various grades (600-1500 grade) have been investigated with the electric resistance measurement. A couple of the base metal was placed in vacuo with their faying surfaces in contact and the electric resistance ρ across the bonding interface was measured while the couple was heated at a constant rate of 15°C/min. The obtained electric resistance in the heating process is analyzed by using the contact parameter W(=nSM/S) which is derived on the basis of the constriction resistance theory. Here Sat is the total area of true metal-to-metal contact spots, N their number per a unit area and S the apparent contact area.
For all the bonding interfaces of aluminum, titanium and copper, the value of ρ decreased in its initial value and approached the resistivity of the base metal more rapidly in the heating process, as the faying surface became rougher. According to an analysis based on the constriction resistance theory, the contact parameter in the heating process for all the base metals was larger when the rough faying surfaces were used.
These results indicate that the disruption of oxide film on the faying surfaces, which prevents true metal-to-metal contact at the bonding interface (as reported in a previous paper), is promoted and so the area and/or number of true metal-to-metal contact spots increase as the faying surface becomes rougher. This fact can be accounted for by the model that the deformation of microasperities on the faying surface leads to the disruption of the oxide film and the degree of the deformation increases as the faying surface, becomes rougher.抄録全体を表示PDF形式でダウンロード (5768K)
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