Steel multilayer tube for gasoline direct injection engines

The line (1) has an inner steel tube (2) accommodated in an outer steel tube (3), where the inner steel tube is made of corrosion resistant steel, and the outer steel tube is made of an outer steel tube alloy. Wall thickness of the inner steel tube is less than a wall thickness of the outer steel tube, and maximum carbon content of the outer steel tube alloy is greater than a maximum carbon content of the corrosion resistant steel. Thickness of the fuel line is ranged between 5 wt.% to 60wt. % of inner diameter of the fuel line.