The invention relates to a
rare earth-containing high-strength
atmospheric corrosion-resistant seamless steel
pipe and a production method thereof, and belongs to the technical fields of
metallurgy and molding. According to the
rare earth-containing high-strength
atmospheric corrosion-resistant seamless steel
pipe, the raw materials comprise 90 wt% of
blast furnace molten iron and 10 wt% of high-quality waste steel; the
pipe billet comprises the following chemical components: 0.05 to 0.10 wt% of C, 0.10 to 0.30 wt% of Si, 1.00 to 1.30 wt% of Mn, less than or equal to 0.020 wt% of P, less than or equal to 0.005 wt% of S, 0.70 to 1.00 wt% of Cr, 0.10 to 0.30 wt% of Mo, 0.20 to 0.40 wt% of Ni, 0.30 to 0.50 wt% of Cu, 0.01 to 0.03 wt% of Ti, 0.01 to 0.04 wt% of Al, 0.0005 to 0.0100 wt% of RE and the balance of Fe and trace elements which cannot be detected. The process flow comprises pretreatment of the molten iron, top and bottom combined blowing converter
smelting,
ladle furnace (LF) refining,
vacuum distillation (VD) vacuum treatment, round billet
continuous casting,
cutting, pipe billet heating, perforation, tandem rolling, reheating,
sizing, cooling, saw
cutting, heat treatment, straightening and flaw detection. The
rare earth-containing high-strength
atmospheric corrosion-resistant seamless steel pipe comprises the following mechanical properties: the yield strength is 620-670 MPa; the tensile strength is 730-820 MPa; the
yield ratio is less than or equal to 0.86; the
extension ratio is more than or equal to 23 percent; the transverse
impact value is more than or equal to 100 J / cm<2> (-40 DEG C); the shear ratio is 100 percent; the grain size is more than or equal to 8.5 level; the
hardness is less than or equal to 22.0 HRC; and the
residual stress is less than or equal to 30 MPa. The seamless steel pipe has the characteristics of high strength, good
toughness, small grain size and good atmospheric
corrosion resistance.