High-strength ship hull structural steel and production method of plate roll

Abstract

The steel for high-strength hull structure and its coil production method belong to low-alloy steel, and especially relates to the steel for hull structure and its production method. The composition (wt%) of steel includes 0.03-0.075%C, 0.01-0.35%Si, 1.40-1.60%Mn, 0.015-0.100%Als, 0.020-0.080%V, and the rest is Fe and impurity elements; its production method is characterized by In the CSP production line, a special temperature system, reduction system and cooling system are adopted. The molten steel is cast by the continuous casting machine, hydraulically sheared into a fixed-length billet, and heated in a soaking furnace. After descaling, the hot billet enters the vertical roller for lateral rolling. The side and seven-stand four-high rolling mills are continuously rolled into strips, and then enter the laminar flow cooling device to control cooling, and finally rolled into coils. The advantages are fewer alloy varieties, simplified process, short production line, less equipment, high production efficiency, high yield, low energy consumption; uniform and stable product performance, high strength; good plate shape, plate thickness, horizontal and vertical dimensions, convexity , High flatness precision, good surface quality, can improve the yield of shipbuilding processing.

Description

technical field [0001] The invention belongs to low-alloy steel, in particular to steel for ship hull structure and its production method. Background technique [0002] With the development of the shipbuilding industry, ordinary marine steel plates can no longer meet the requirements of large-scale and professional ships, and people prefer low-alloy steel with excellent performance. Chinese national standard GB712-2000 discloses high-strength ship steel composition (wt%) C≤0.18%, Si≤0.50%, 0.90-1.60% Mn, Als≥0.015, 0.02-0.05% Nb, 0.05-0.10% V, Ti≤0.02%, Cu≤0.35%, Cr≤0.02%, Ni≤0.40%, Mo≤0.08%, and the rest are Fe and impurity elements. There are as many as 11 alloying elements in this kind of steel. The disadvantage is that there are many kinds of alloys to be added, and some alloying elements are expensive, which increases the cost of steelmaking and brings inconvenience to steelmaking production. Nowadays, steel plates for hull structures are mostly produced by convention...

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Problems solved by technology

Its disadvantages are complex process, many equipments, long production line and high infrastructure investment; long production cycle, which takes more than 2 days from smelting molten steel to rolling into ship plate, which takes up a lot of working capital; secondary heating of slab, high energy consumption; The heating temperature of the slab is unstable, and the cross-section temperature distribution along the length and width direction is uneven, which affects the performance of the ship plate, and affects the accuracy of the thickness, convexity, flatness and width of the plate: the yield is low, generally 88%; due to the Due to the limitations of rolling mills and other aspects, it is even more difficult to produce thin-gauge ship plates

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