Excellent 100 kg-grade quenched and tempered steel plate with strong toughness and plasticity, and manufacturing method thereof

Abstract

The invention discloses an excellent 100 kg-grade quenched and tempered steel plate with strong toughness and plasticity, and a manufacturing method thereof. The excellent 100 kg-grade quenched and tempered steel plate with strong toughness and plasticity comprises: by weight, 0.09 to 0.15% of C, less than or equal to 0.10% of Si, 0.70 to 1.10% of Mn, less than or equal to 0.013% of P, less than or equal to 0.0030% of S, 0.20 to 0.45% of Cu, 1.30 to 2.00% of Ni, 0.45 to 0.85% of Cr, 0.45 to 0.75% of Mo, 0.045 to 0.070% of Als, 0.008 to 0.025% of Nb, 0.030 to 0.060% of V, 0.004 to 0.010% of Ti, less than or equal to 0.0060% of N, 0.001 to 0.005% of Ca, 0.0006 to 0.0014% of B, and the balance Fe and unavoidable impurities. Through a technology (RQ+RQ+T) combining optimally controlled rolling and offline special conditioning, the excellent 100 kg-grade quenched and tempered steel plate with strong toughness and plasticity forms a microstructure composed of a fine tempered lower bainite and a tempered martensite, wherein an average size of druses is below 20 micrometers; tensile strength is great than or equal to 980MPa; yield strength is great than or equal to 890MPa; and single transverse Charpy impact energy (-60 DEG C) is great than or equal to 47J. Therefore, the excellent 100 kg-grade quenched and tempered steel plate with strong toughness and plasticity has excellent weldability and can solve the problem of over-quenching of a surface of a steel plate with ultra-high strength.

Description

technical field [0001] The present invention relates to a high-strength steel plate and a manufacturing process thereof, in particular to a 100-kilogram quenched and tempered steel plate with excellent toughness and strong plasticity and a manufacturing method thereof. Specific transverse impact energy (single value) ≥ 47J, with excellent weldability. Background technique [0002] As we all know, low-carbon (high-strength) low-alloy steel is one of the most important engineering structural materials, widely used in oil and gas pipelines, offshore platforms, shipbuilding, bridge structures, boiler containers, building structures, automobile industry, railway transportation and machinery manufacturing. The performance of low-carbon (high-strength) low-alloy steel depends on its chemical composition and manufacturing process, among which strength, toughness, plasticity and weldability are the most important properties of low-carbon (high-strength) low-alloy steel, which are ult...

AI Technical Summary

Problems solved by technology

[0005] A large number of existing patents and technical documents only explain how to realize the strength and low-temperature toughness of the base steel plate, improve the weldability of the steel plate, and obtain excellent welding heat-affected zone HAZ low-temperature toughness. At the same time, it improves the tensile elongation of the steel plate and the uniformity of the mechanical properties in the thickness direction, and it does not point out how to prevent the surface (sub) surface layer of the steel plate from overquenching.

Images