Manufacturing method of fine-grain high-strength anti-seismic reinforcing steel bar with high tensile-to-yield ratio

Abstract

The invention discloses a manufacturing method of a fine-grain high-strength aseismic steel bar with a high yield ratio, and the fine-grain high-strength aseismic steel bar comprises the following chemical components in percentage by weight: 0.22%-0.25% of C, 0.25%-0.45% of Si, 1.35%-1.60% of Mn, less than or equal to 0.030% of P, less than or equal to 0.030% of S, 0.12%-0.20% of Cr, 0.050%-0.120% of V and the balance of Fe. The technology operability is high, the produced 500 MPa aseismic steel bar has the product performance that rel is larger than or equal to 520 MPa, rm is larger than or equal to 700 MPa, Agt is larger than or equal to 12%, the strength-to-yield ratio is larger than or equal to 1.35, the metallographic structure is P and F, P accounts for 40% or above, the grain size is larger than or equal to the level 9, all indexes meet and are higher than the national standard requirement, and the product quality is stable and has the advantages of being high in strength and aseismic property, fine in grain and the like.

Description

Technical field [0001] The present invention relates to the technical field of high-strength anti-resist steel bars, and is specifically a high-strength abundant fine grain high-strength anti-resist steel bar manufacturing method. Background technique [0002] In view of the fact that my country's earthquake, the seismic performance of building steel bars has attracted high concern, and related regulations in some architectural design specifications, the yield strength and strongness of architectural steel bars have an important impact on the use of materials, including steel bars The earthquake resistance is mainly determined by the high and low of the stronglex ratio. The new national standard for GB / T 1499.2 requires a strong beam ratio ≥1.25% for earthquake-resistant steel bars. At this stage, the 400MPA-level hot rolled steel bar promoted by the market is basically achieved by microalloy. Standard requirements, but 500MPa and 600MPa high-strength steel bars are very low in...

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Problems solved by technology

[0002] In view of the frequent occurrence of earthquakes in my country, the seismic performance of building steel bars has attracted great attention, and relevant regulations have been made in some building design codes. The yield strength and strength-to-yield ratio of building steel bars have an important impact on the performance of materials. The seismic performance is mainly determined by the strength-to-yield ratio. The new national standard GB / T 1499.2 requires a strength-to-yield ratio of ≥1.25%, and the 400MPa-grade hot-rolled steel bars popularized and applied in the market at this stage can basically achieve the strength-to-yield ratio through microalloy strengthening. Standard requirements, but the pass rate of the strength-to-yield ratio of 500MPa and 600MPa high-strength steel bars in actual production is very low, basically between 1.20% and 1.27%, which creates great difficulties for the popularization and application of high-strength seismic steel bars

[0003] At present, the production of high-strength anti-seismic steel bars mostly adopts micro-alloy strengthening technology and hot-rolling deformation heat treatment process. By adding micro-alloying elements such as V, Ti, Nb and controlling the temperature of the rolling process, the grains of the steel bars are refined, and the grains can be refined at the same time. Improve the strength and toughness of the steel bar, but the contribution of the refined grain to the tensile strength is very small. Both will increase the yield strength greater than the tensile strength, resulting in a decrease in the strength-to-yield ratio of the steel bar and low seismic performance.

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