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■■■■■■■■■■■■■■■■■■■ 川崎製鉄技報 KAWASAKI STEEL GIHO Vol.4 (1972) No.3 ■■■■■■■■■■■■■■■■■■■ |
| ASTM A387 Gr. D極厚鋼板について On Heavy Gauge ASTM A387 Gr. D Steel Plate 佐藤 新吾(Shingo Sato) 榎並 禎一(Teiichi Enami) 楠原 祐司(Yugi Kusuhara) 林 忠男(Tadao Hayashi) |
| 要旨 : 水島製鉄所において，取鍋精錬炉，6000ｔプレスおよび厚板圧延機を用いて，200mm厚さのASTM A387 Gr. D鋼板が試作され，内部性状，機械的性質におよぼす熱処理条件の影響が調査された。さらに，A387D鋼の機械的性質におよぼすMn, Ni, Cu, V, Nb,およびAlの影響が調べられ強度を増加させる方法が検討された。この結果，200mm極厚鋼板における内部性状の健全性が確認され，板厚，応力除去焼きなまし条件の変化にたいして，要求される機械的性質を得る方針が明らかになった。 |
| Synopsis : At Mizushima Works, a 200mm thick plate of ASTM A387 Grade D was made by using Ladle-Refining-Furnace, 6000t forging press and plate mill. The soundness of the plate, the effect of heat treating conditions on mechanical properties and so forth were investigated. The effect of such alloying elements as Mn, Ni, Cu, V, Nb and Al on mechanical properties was also investigated, the possibilities of the improvement in the tensile property of A387 D were discussed. The followings were obtained from these efforts: (1) In spite of its weigher ingot and large thickness, the plate showed a very small amount of non-metallic inclusion, without any defect. (2) The range of heat treatment was clarified which can satisfy the requirement of the mechanical properties for a standard composition. (3) Change in cooling rate during quenching did not affect the strength as long as proeutectoid ferrite did not formed. (4) The hardness was lowered in linear manner with the amount of proeutectoid ferrite formed during quenching. (5) An increase in Mn content to 0.8% or additions of 0.2% Ni and/or 0.2% Cu inhibited proeutectoid ferrite from forming during quenching. Coarse austenite grain was useful in preventing the precipitation of proeutectiod ferrite. (6) An increase in Mn or an addition of Cu increased hardness for all conditions of stress relief annealing. But, an addition of 0.2% Ni had no effect on hardness. (7) An addition of 0.05% Nb increased hardness in the range of severer conditions in stress relief annealing. |
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