Automobile beam steel which is low in carbon equivalent, easy to weld and more than 750Mpa in yield strength and fabrication method thereof

The invention relates to automobile beam steel which is low in carbon equivalent, easy to weld and more than 750Mpa in yield strength and a fabrication method thereof. The steel is composed of, by weight, 0.03%-0.05% of C, 0.06-0.15% of Si, 1.80%-1.85% of Mn, 0.010%-0.015% of P, 0.001%-0.003% of S, 0.065%-0.085% of Nb, 0.12%-0.18% of Mo, 0.15%-0.16% of Ti, 0.0015%-0.0045% of Ca, 0.02%-0.05% of Al and the balance Fe and unavoidable impurities. The method includes steel making, continuous casting, heating, hot continuous rolling, laminar cooling, coiling, slow cooling and finishing. High strength and high tenacity of the automobile beam steel can be guaranteed, meanwhile, low-cost welding wires can be used, and the problems of segregation and surface qualities are avoided.