60 Kg-scale low temperature-quenched and tempered steel plate with good weldability and manufacture method thereof

Abstract

The invention discloses 60 Kg-scale low temperature-quenched and tempered steel plate with good weldability and manufacture method thereof. The steel plate includes (by weight percentage) C 0.035-0.075, Mn 1.30-1.60, Si less than or equal to 0.20, P less than or equal to 0.013, S less than or equal to 0.0030, Cu 0.10-0.40, Ni 0.30-0.70, Cr 0.05-0.30, Mo 0.10-0.30, Als 0.030-0.060, Nb 0.008-0.030, Ti 0.006-0.012, V 0.030-0.060, N 0.0035-0.0060, Ca 0.001-0.004, and Fe and unavoidable impurity in balance. By optimized controlled rolling and offline low temperature quenching and tempering process, the microscopic structure of the product steel plate is superfine tempered upper bainite (minute quantity of lower bainite may exist), with average packet size smaller than 15 Mum; and high toughness / high toughness match and uniform elongation are achieved, and in the meantime, steel plate weldability is also excellent.

Description

technical field [0001] The present invention relates to a quenched and tempered steel plate and a manufacturing method thereof, in particular to a 60-kilogram low-temperature quenched and tempered steel plate with excellent weldability and a manufacturing method thereof. Low-temperature quenched and tempered steel plate with specific transverse impact energy (single value) ≥ 80J and excellent weldability; Background technique [0002] 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. [0003] The properties of low-carbon (high-strength) low-alloy steel depend on its chemical composition and the process system of the manufacturing process, among which strength, toughness and weldability are the most important properties ...

AI Technical Summary

Problems solved by technology

[0007] The object of the present invention is to provide a 60 kg class low-temperature quenched and tempered steel plate with excellent weldability and its manufacturing method. Through the combined design of steel plate alloy elements, the combination of the controlled rolling process and the low-temperature quenched and tempered process, the quenched and tempered state microstructure can be realized. Refined control, while obtaining excellent low-temperature quenched and tempered steel plate strength, low-temperature toughness and strength-toughness matching, the weldability of the steel plate is also excellent, and successfully solved the problem of -60℃ low-temperature toughness and uniform tensile strength of 60kg-grade quenched and tempered steel plate The problem of low elongation; this is one of the biggest difficulties in the development of steel types, and it is also a key core technology

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