1000Mpa grade high-tenacity high-property-uniformity super-thick steel plate easy to weld and manufacturing method thereof

Abstract

The invention relates to a 1000MPa grade high-tenacity high-property-uniformity super-thick steel plate easy to weld. With Fe as the basic element, the steel plate comprises the chemical components of, by mass, 0.12-0.15% of C, 0.15-0.35% of Si, 0.95-1.20% of Mn, no more than 0.010% of P, no more than 0.002% of S, 0.5-0.8% of Cr, 0.4-0.6% of Mo, 2.4-3.0% of Ni, 0.2-0.4% of Cu, 0.06-0.09% of Al, 0.03-0.06% of V, no more than 0.04% of Nb, no more than 0.006% of N, 0.001-0.002% of B and impurity elements. When the carbon equivalent is no more than 0.75%, the thickness of the steel plate reaches 180 mm. According to the 1000MPa grade high-tenacity high-property-uniformity super-thick steel plate easy to weld, in order to meet requirements of large engineering equipment, a high-quality and high-purity continuous casting sheet billet produced by means of the optimized chemical components, high-purity molten steel and an optimized continuous casting process is adopted as a billet material, and the super-thick steel plate meeting the requirements is manufactured through a method of controlling rolling, quenching and low-temperature tempering.

Description

technical field [0001] The invention belongs to the technical field of special steel plates, and in particular relates to a 1000MPa extra-thick steel plate and a manufacturing method thereof. Background technique [0002] Large-scale engineering equipment requires high-strength, high-toughness, high-performance uniformity, and large-thickness steel plates that are easy to weld. Chinese invention patents with patent publication numbers CN100494451, CN103014538B, CN102618793B, CN101935810B, CN105189802A, CN101397640A, CN101451221A, and CN102234743A disclose that continuous casting slabs or steel ingots are used as raw materials, and added back to direct quenching or off-line quenching (DQ) after rolling. Huolai manufactures high-strength steel plates with a yield strength of about 1000 MPa and its manufacturing methods. However, the thickness of steel plates produced by these inventions is small, ≤80mm, which cannot meet the requirements of some large-scale engineering equipm...

AI Technical Summary

Problems solved by technology

However, the tensile and impact properties disclosed in this invention do not distinguish the position in the thickness direction of the steel plate, and the changes of these properties with position on the thickness section are not disclosed

According to various standards for sampling and testing steel plate mechanical properties, the value disclosed in this invention only represents the tensile and impact properties at 1 / 4 thickness of the steel plate, and cannot represent the tensile and impact properties at 1 / 2 thickness of the steel plate, moreover It cannot represent the uniformity of properties in the thickness direction of the steel plate

In this way, the steel plate produced by the invention cannot be used for the manufacture of equipment that requires both tensile and impact properties at the 1 / 4 thickness and 1 / 2 thickness of the steel plate, and it cannot be used for high performance uniformity in the thickness direction of the steel plate. It is required for the manufacture of equipment, and it cannot be used for the manufacture of equipment requiring the thickness of the steel plate to exceed 160mm

In addition, in the prior art, the continuous casting slab composite method is used to form composite slabs and manufacture large-thickness steel plates accordingly, which makes the production process complicated and the manufacturing cost significantly increased

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