The effects of substituting Ti for V on mechanical properties in a weathering type HSLA steel (USS COR-TEN C steel) were studied. Mechanical tests were performed on both controlled rolled and normalized state. Ti added steel exhibited higher yield strength (10% increase) and tensile strength (about 14% increase) compared with V contained alloy. The high cycle fatigue properties were also greatly improved by substituting Ti for V in the weathering type HSLA steel. Ti added alloy showed poor impact properties due to increase of strength by precipitation hardening.