Nb and N composite reinforced 400 MPa grade steel bar and manufacturing method thereof

Abstract

The invention provides a Nb and N composite reinforced 400 MPa grade steel bar. The Nb and N composite reinforced 400 MPa grade steel bar is prepared from the following components in percentage by mass: 0.20-0.25% of C, 1.25-1.60% of Mn, 0.008-0.04% of Nb, 0.006-0.012% of N, less than or equal to 0.35% of Si, less than or equal to 0.045% of P, less than or equal to 0.045% of S, the balance of ironand inevitable impurity elements. The product yield strength of a ribbed steel bar finished product can stably reach more than 420 MPa, and the good anti-seismic performance is achieved.

Description

technical field [0001] The present application relates to the technical field of hot-rolled ribbed steel bar rolling, and in particular, relates to a Nb, N composite strengthened 400MPa grade steel bar and a manufacturing method thereof. Background technique [0002] Micro-alloying of steel and controlled rolling and controlled cooling are very beneficial to improving the performance of steel and reducing manufacturing costs. Microalloyed steel is a high-tech steel product produced by modern metallurgical production processes. It is alloyed by adding a small amount (mass fraction is usually less than 0.1%) of strong carbonitride-forming elements (such as niobium, vanadium, titanium, etc.) to ordinary C-Mn steel or low alloy steel, through high-purity smelting Process (degassing, desulfurization and inclusion shape control) steelmaking, new processes such as controlled rolling / controlled cooling are applied in the processing process, and by controlling the physical metallurg...

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Problems solved by technology

Patent CN101538677A discloses a HRB500E fine-grained anti-seismic steel bar manufactured by Nb microalloying. The steel is strengthened by fine-grained reinforcement. The heating temperature and rolling temperature are controlled in the low temperature area, the rolling speed is slow, and the production efficiency is low. And there is no explanation as to whether there is obvious yield in the tensile test of the steel bar containing Nb

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