Steel plate uniform in longitudinal performance and obtained by normalizing rolling and manufacturing method therefor

Abstract

The invention discloses a steel plate uniform in longitudinal performance and obtained by normalizing rolling and a manufacturing method therefor. The steel plate comprises the following components: C, Mn, Ti, Si, N, Als, P, S and the balance Fe and impurities, and the components are necessary to limit in element content simultaneously: 83%Si + 354%N > 23; and according to the manufacturing method, medium and low carbon is employed on the composition of a steel grade, and N and Ti low in cost serve as main strengthened alloy elements to limit the addition ratio of Si to N; and then, under thesupplement of a right amount of Mn, the content of P and S of harmful elements is strictly controlled. The yield strength of the steel plate provided by the invention is 370-432 MPa at normal temperature, the tensile strength is 533-566 MPa, the ductility is 25-30.5 %, and the impact energy is 185-231 J at -20 DEG C; moreover, the intra-plate longitudinal strength difference is 5-24 MPa, and the intra-plate tensile strength difference is 2-17 MPa; the steel plate produced by employing the method has mechanical property equivalent to the mechanical property of a steel plate hot treated by normalizing, and has uniform longitudinal performance; the production cost is greatly reduced; process flows are reduced; the production efficiency and the economic benefit are increased; and the method has great popularizing significance.

Description

Technical field [0001] The invention relates to the technical field of steel manufacturing, in particular to a steel plate with uniform longitudinal properties obtained by normalizing rolling and a manufacturing method thereof. Background technique [0002] In recent years, the use of low-alloy steel plates in the market has become more and more extensive, and the quality requirements of low-alloy steel plates have become higher and higher, especially in some special geographic environments such as high-cold areas or key pressure-bearing structural parts. Low-alloy steel plates should have a more uniform structure, stable physical and chemical properties, and good fatigue resistance. In this regard, ordinary low-alloy steel sheets no longer meet the quality demands of customers. The normalizing process, as a heat treatment process that can refine austenite grains and improve the mechanical properties of steel plates, is widely used in structural steels. It can reduce the differe...

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Problems solved by technology

[0005] The purpose of the present invention is to address the deficiencies in the prior art, to propose a steel plate with uniform longitudinal properties obtained by normalizing rolling and a manufacturing method thereof, so as to solve the problem of poor uniformity of the longitudinal properties of the existing steel plates or the heat treatment process for obtaining steel plates with uniform longitudinal properties cumbersome, long cycle, high cost and other issues, the thickness of the steel plate is 10-100mm, normalized rolling is adopted in the process, the yield strength at room temperature is 370-432MPa, the tensile strength is 533-566MPa, and the elongation is 25-30.5% , The impact energy at -20°C is 185~231J, and the longitudinal strength difference of the same board is 5~24MPa, the tensile strength difference of the same board is 2~17MPa, and the longitudinal performance is uniform

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