| 摘要 |
PURPOSE: A hot rolled steel sheet and a manufacturing method thereof are provided to have the steel sheet with improved moldability by increasing the elongation ratio of the steel sheet. CONSTITUTION: A hot rolled steel sheet is made of niobium 0.02~0.10 weight%, vanadium 0.02~0.10 weight%, carbon 0.08~0.20 weight%, silicon 0.0005~1.00 weight%, manganese 1.50~2.50 weight%, aluminum 0.0005~0.10 weight%, nitrogen 0.01 weight%, sulfur 0.01 weight%, zirconium 0.02~0.10 weight%, chrome 0.10~ 0.50 weight%, boron 0.0005~0.0050 weight%, and phosphorus 0.05 weight%. Micro-structure comprises 40~100vol% martensite structure. |
