High-manganese medium-thickness steel plate for ocean engineering and production method thereof

Abstract

The invention discloses a high-manganese medium-thickness steel plate for ocean engineering and a production method thereof. The steel contains 0.05%-0.25% of C, 5.0%-9.0% of Mn, 0.20%-0.50% of Si, 0.10%-0.50% of Cu, 0.25%-0.40% of Ni, 0.30%-0.90% of Cr, 0.25%-0.80% of Mo, 0.001%-0.007% of N, smaller than or equal to 0.01% of P, smaller than or equal to 0.01% of S, 0.01%-0.05% of Al and the balance of Fe and inevitable impurities. The heating temperature is 1140 to 1220 DEG C. The first-stage initial rolling temperature is greater than or equal to 1000 DEG C. The single-pass reduction rate isgreater than 13%. The cumulative reduction rate is 40%-50%. The second-stage final rolling temperature is 850-900 DEG C. The single-pass reduction rate is 5%-12%. The cumulative reduction rate is 50%-60%. The cooling speed is 3-7 DEG C / s. The re-reddening temperature is 300-450 DEG C and the hardening and tempering treatment is conducted finally. The thickness of the steel plate is 30-65mm. The steel plate is excellent in low-temperature toughness, and no cold crack exists on the surface of the steel plate after rolling.

Description

technical field [0001] The invention belongs to the technical field of medium-thick steel plate preparation, and in particular relates to a composition design and a rolling method of a high-manganese medium-thick steel plate suitable for ocean engineering. Background technique [0002] Medium-high manganese steel is widely used in wear-resistant parts, automobiles, mining machinery and offshore platforms in modern society. Because medium-high manganese steel has good tensile and low-temperature toughness, it is especially suitable for the reduction of steel plates in the field of marine engineering. However, steel generally contains high Mn content, so whether it is smelting or rolling, it is a steel type that is difficult to produce. Although high-manganese steel has good tensile and low-temperature toughness, it is considered to be a steel grade that can make up for the expensive cost of Ni-based low-temperature steel, but the processing performance of high-manganese cont...

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Problems solved by technology

The Mn content is low, and the advantages of Mn steel cannot be fully utilized. Without proper use of Cr, Mo, Ni, Cu and other alloys to form an effective second phase precipitation strengthening, it cannot effectively prevent the steel plate from slowly Cold cracks that appear during cooling

In addition, the steel plate produced is a cold-rolled coil, and the thickness of the product is not specified, so hot-rolled medium and heavy plates with a thickness of 30-65 mm cannot be produced

[0004] CN101550515A discloses a copper-containing high-strength and tough high-manganese steel and its manufacturing method. The high-manganese steel is used for automobile plates, and the thickness is not required. It is not suitable for 30-65mm large-thickness marine engineering steel plates. No consideration is given to improving the as-cast structure

[0005] CN104805378A discloses a high-strength ultra-low-carbon medium-manganese steel medium-thick plate and its preparation method. The thickness of the produced steel plate is 20-50 mm, which is not suitable for producing thick plates with greater thickness

The rolling process cannot effectively solve the problem of different properties in the thickness direction during the rolling process

[0006] CN102534406A discloses medium manganese steel and its preparation method. It is electric furnace smelting and sand casting medium manganese steel, which cannot produce continuous casting hot rolled large thickness high manganese steel plate

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