Preparation process and steel material for enhancing the performance of high-strength steel by using acicular ferrite structure

Abstract

The invention provides a preparation process for enhancing the performance of high-strength steel with acicular ferrite structure and the steel. The yield strength of the acicular ferrite high-strength steel is ≥ 400 MPa, and the steel contains the following chemical composition in weight percentage: C: 0.17 ~0.25%, Si: 0.40~0.80%, Mn: 1.20~1.60%, S: ≤0.045%, P: ≤0.045%, Ca: 0.005~0.035%, Ni: 0.010~0.015%, Cu: 0.015~0.050% , and the rest are Fe and unavoidable impurities. In the present invention, after the molten steel is tapped, calcium carbide is used for final deoxidation of the molten steel. The calcium carbide will generate CaO inclusions during the violent reaction, and the generated CaO inclusions will be distributed in a dispersed state while CO bubbles are generated. A large number of fine CaO inclusions dispersedly distributed as The heterogeneous nucleation core induces the formation of intragranular acicular ferrite, refines or divides the original austenite grains, makes the steel structure more refined, and the strength and toughness are greatly improved.

Description

[0001] 【Technical field】 [0002] The invention belongs to the technical field of high-strength steel for construction, and relates to a production process for producing high-strength steel by using calcium-based oxide metallurgy technology, in particular to a preparation process for enhancing the performance of high-strength steel by using acicular ferrite structure. [0003] 【Background technique】 [0004] With the development of my country's economic construction, more and more super high-rise buildings, long-span buildings, high-seismic buildings, and large-scale infrastructures are emerging, and the demand for high-strength steel is increasing, and its performance requirements are also increasing. come higher. High-strength steel refers to steel with a strength level above 400MPa, which meets the requirements of HRB400 and HRB500 grade steel specified in the national standard GB1499, and has the characteristics of high strength and excellent comprehensive performance. The ...

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Problems solved by technology

[0009] Aiming at the problems of high-strength steel consumption and high cost in the production of high-strength steel by micro-alloying technology, the present invention proposes a preparation process and steel that use acicular ferrite structure to enhance the performance of high-strength steel, and utilize calcium-based oxide metallurgy technology In the production of high-strength steel, a certain amount of calcium carbide is added to the crystallizer to deoxidize again after tapping molten steel, so that a large number of fine inclusions such as calcium oxide are formed in the steel, and calcium-based composite inclusions serve as heterogeneous nucleation cores to promote crystallization. The formation of inner acicular ferrite refines the original austenite grains, thereby improving the strength and toughness of steel

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