| 摘要 |
<p>PURPOSE: A base material, a component thereby, and a manufacturing method thereof, capable of omitting a spheroidizing heating process are provided to include high intensity organization with excellent resistivity on delayed fracture after cold working. CONSTITUTION: A base material capable of omitting a spheroidizing heating process is comprised of 0.25 ~ 0.45 weight% of C, 0.1~0.2 weight% of Si, 0.1~0.7 weight% of Mn: 0.005 ~ 0.02 weight% of Sb, remainder Fe, and unavoidable impurity. A grain size of austenite is 50μm or less. Ferrite is included over 60 area %. A content of the Ti, the Nb, and V is restrained to under total 0.01 weight%. The component includes an internal organization comprised of tempered maftensite, and a lath size of the tempered maftensite is under 0.3μm. The contect of the Ti, the Nb, and the V is under total 0.01 weight %. [Reference numerals] (AA,CC) Existing material hardness Hv 282; (BB,DD) Invented material hardness Hv 342</p> |
