HRB400E ordinary-speed hot-rolled ribbed steel bar with tensile strength of 700 Mpa or above and production method thereof

Abstract

The invention provides an HRB400E ordinary-speed hot-rolled ribbed steel bar with the tensile strength of 700 Mpa or above and a production method thereof. The production method of the HRB400E ordinary-speed hot-rolled ribbed steel bar with the tensile strength of 700 Mpa or above comprises the following process stages which are sequentially carried out: blast furnace molten iron smelting, molten iron desulfurization pretreatment, converter molten steel smelting, LF refining, square billet continuous casting, hot continuous rolling and fixed-length shearing; and the HRB400E ordinary-speed hot-rolled ribbed steel bar is prepared from the following components in percentages by weight: 0.19 to 0.25 percent of C, 0.60 to 0.80 percent of Si, 1.45 to 1.60 percent of Mn, less than or equal to 0.040 percent of P, less than or equal to 0.035 percent of S, 0.065 to 0.10 percent of V, 0.010 to 0.022 percent of Nb, 0.008 to 0.020 percent of N and 0.0020 to 0.0050 percent of B. By means of the method, the tensile strength of the HRB400E straight hot-rolled ribbed steel bar with the specification of phi 10-40 mm can be improved to 700 Mpa or above, the yield ratio R degree m/R degree eL is larger than or equal to 1.45, and a hot-rolled ribbed steel bar product with the anti-seismic property better than that of the conventional HRB400E is obtained.

Description

technical field [0001] The invention belongs to the field of iron and steel production and manufacturing, and relates to a common HRB400E hot-rolled ribbed steel bar with a tensile strength of more than 700Mpa and a production method thereof, or a normal-speed HRB400E hot-rolled ribbed steel bar with a tensile strength of more than 700Mpa and a production method thereof . Background technique [0002] HRB400E seismic steel bars are widely used due to their high strength and good seismic performance. In GB / T 1499.2-2018 "Steel for Reinforced Concrete Part 2: Hot-rolled Ribbed Steel Bars", the plasticity index of HRB400E seismic steel bars (such as: maximum force total Elongation A gt , Strength ratio R° m / R° eL , R° eL / R eL and other indicators) have clear requirements. The tensile strength of conventional HRB400E seismic steel bars is about 600MPa. Under the premise of meeting the plasticity index in the national standard, the higher the tensile strength, it means th...

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Problems solved by technology

[0004] The present invention provides a HRB400E ordinary-speed hot-rolled ribbed steel bar with a tensile strength above 700Mpa to solve the problems of the existing ordinary-speed (non-high-bar) HRB400E seismic steel bar with low tensile strength and low yield ratio

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