自動車鋼管の加工性におよぼす素材帯鋼の製造条件の影響

概要

論文の詳細を見る
The effect of manufacturing condition of hot rolled steel sheet on the formability of steel tube for automobile was studied. The steel tubes used in this investigation were classified by the tube sizes ; 75φ×1.6mm and 45φ×5.0mm (tensile strength range from 30 to 60kg/mm^2). The main results obtained are as follows : (1) An intermediate stage microstructure at the welded parts is found when carbon equivalent (C+1/7Si+1/4Mn) of steel is above 0.28%, and it is remarkable in the case of a higher tensile strength, thinner thickness tube. (2) The 90°flattening value and flaring formability of steel tube deteriorate when tensile strength of the material increases. In the flare forming test of thicker tubes, when the tensile strength of the material increases above 50kg/mm^2, the position of crack transfers from the non welded part to the welded part, and the formability decreases remarkably. Expanding formability is more intensely affected by the non-metallic inclusions and the banded structure than by the tensile strength of the material. (3) The formability of steel tube is closely related to [C_<eq>(%)+5(S%+1/2P%)] of the material, regarding the expand forming, however, it is necessary to estimate the coefficient of S% and P% to be higher than in this formula.
社団法人日本鉄鋼協会の論文
1974-12-01