Patent ID: 8152939

Claim:
A non-heat treated fracture splitting connecting rod which comprises, in % by mass, C: 0.25 to 0.35%, Si: 0.50 to 0.70%, Mn: 0.60 to 0.90%, P: 0.040 to 0.070 %, S: 0.040 to 0.130%, Cr: 0.10 to 0.20%, V: 0.15 to 0.20%, Ti: 0.15 to 0.20% and N: 0.002 to 0.020%, with the balance being Fe and impurities, with chemical compositions being less than 0.80 in the value of Ceq stated by the following expression (1), the microstructure of the big end of the said connecting rod being ferrite-pearlite, all-region hardness of the said big end being 255 to 320 in Vickers hardness, the ferrite-region hardness in the said ferrite-pearlite of the big end being 250 or more in Vickers hardness and the ratio of the said ferrite-region hardness to the said all-region hardness of said big end being 0.80 or more; C eq =C+(Si/10)+(Mn/5)+(5Cr/22)+1.65V−(5S/7) (1), where an element symbol appearing in the expression (1) represents the contents in mass % of the corresponding elements in the steel.