Steel plate with thickness of 80mm and low compression ratio for ocean engineering and manufacturing method thereof

Abstract

The invention relates to steel for ocean engineering and a manufacturing method thereof, in particular to a steel plate with a thickness of 80mm and a low compression ratio for ocean engineering and a manufacturing method thereof. The steel plate comprises the chemical components with the weight percentages as follows: 0.12 to 0.16 percent of C, 0.20 to 0.40 percent of Si, 1.20 to 1.60 percent ofMn, smaller than or equal to 0.010 percent of P, smaller than or equal to 0.003 percent of S, 0.025 to 0.050 percent of Nb, 0.030 to 0.050 percent of V, 0.010 to 0.020 percent of Ti, smaller than or equal to 0.20 percent of Cr, 0.10 to 0.40 percent of Ni, smaller than or equal to 0.20 percent of Cu, smaller than or equal to 0.08 percent of Mo, 0.0250 to 0.050 percent of Al, smaller than or equal to 20ppm of O, smaller than or equal to 40ppm of N, smaller than or equal to 3ppm of H, and the remaining amount of Fe and inevitable impurities. A controlled rolling and cooling technology is adopted, the heating temperature before rolling is 1180 DEG C to 1250 DEG C, the rough rolling temperature is 1000 to 1100 DEG C, and the finish rolling starting temperature is 850 to 880 DEG C; laminar cooling is conducted after the rolling, the final cooling temperature is 640 to 680 DEG C, and the cooling rate is 5 to 15 DEG C/s; and normalizing treatment is conducted, the normalizing temperature is 890 to 910 DEG C, the heating rate is 1.4min/mm, and the heat preservation time is 50 to 90min. The obtained steel has the characteristics of high strength, good Z-direction lamellar tearing resistant performance, high plasticity, and the like.

Description

technical field [0001] The invention relates to a steel for marine engineering and a manufacturing method thereof, in particular to a steel plate with a thickness of 80 mm and a low compression ratio for marine engineering and a manufacturing method thereof. Background technique [0002] With the continuous development of the economy, the demand for oil and natural gas energy in various countries has increased sharply. Land resources are becoming less and less, and mining is becoming more and more difficult. Offshore oil and natural gas resources have become a new growth point for exploitation, and the offshore engineering equipment manufacturing industry has also followed It has become a key field for the development of countries in the world, especially energy-deficit countries. [0003] The high-strength and toughness E36-Z35 steel plate with a thickness of 60-80mm is the steel used for key parts of marine engineering. It is used in severe marine working environments such...

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Problems solved by technology

[0004] At present, a small number of domestic enterprises have the ability to produce 80mm high-strength and toughness E36-Z35 steel plates, but the thickness of the continuous casting billet is ≥300mm, and the rolling mill uses a 4300 or 5000mm wide and thick plate rolling mill, and the rolling mill has a large rolling force

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