High-hardenability and high-strength ultra-thick marine steel plate and production method thereof

Abstract

The invention relates to a high-hardenability and high-strength ultra-thick marine steel plate. The high-hardenability and high-strength ultra-thick marine steel plate is 60-150 mm thick and is composed of the chemical components of, by weight percentage, 0.04-0.08% of C, 4-9% of Mn, 0.10-0.25% of Si, 0.01-0.03% of Als, 0.2-0.5% of Mo, 0.025-0.050% of Nb, less than or equal to 0.04% of S, less than or equal to 0.007% of P, and Fe and impurity elements as balance. The high-hardenability and high-strength ultra-thick marine steel plate can solve the phenomenon of non-uniformity of thickness direction texture and performance, expand the thickness specification to 150 mm with low-temperature toughness still meeting the operating requirements at -80 DEG C and obtain low yield ratio under equal yield strength conditions, specifically, the parts of 1 / 4 and 1 / 2 thickness of the steel plate reach a yield strength not lower than 690 MPa, a yield ratio not higher than 0.86, an elongation percentage not lower than 20%, and a -80 DEG C low-temperature impact energy greater than 100 J.

Description

technical field [0001] The invention relates to a marine engineering steel and a preparation method thereof, in particular to a high-hardenability, high-strength and toughness extra-thick marine engineering steel plate and a preparation method thereof. Background technique [0002] The 21st century is the century of the ocean. With the development of the world economy, both marine transportation and marine resource development will enter a period of rapid development, which will drive the rapid growth of shipbuilding and marine engineering manufacturing. Large-scale ships and deep-sea development of marine resources will use a large number of ship and marine steels with special properties. At present, my country's shipbuilding and marine engineering steel has been able to meet most of the needs of the domestic market, but some high-grade special steel products still rely heavily on imports. Special steel mainly refers to steel plates with high strength, large thickness, lam...

AI Technical Summary

Problems solved by technology

[0006] The technical problem to be solved by the present invention is: how to solve the phenomenon of uneven microstructure and properties in the thickness direction of the steel plate, and at the same time widen the thickness specification to 150mm, and the low temperature toughness can still meet the service requirements of -80°C, and have low yield under the same yield strength condition Strength ratio; specifically how to produce steel plates with thickness ≥ 60-150mm, yield strength ≥ 690MPa at 1 / 4 and 1 / 2 of steel plate thickness, yield ratio ≤ 0.86, elongation ≥ 20%, and impact energy at -80°C low temperature > 100J Extra thick marine steel

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