Q 390E class super-thick steel plate with thickness of 100mm and manufacturing method thereof

Abstract

The invention discloses a Q 390E class super-thick steel plate with the thickness of 100mm and a manufacturing method thereof. The steel plate has the chemical composition of steel by weight percent: 0.08-0.13% of C, 1.20-1.60% of Mn, 0.10-0.25% of Si, less than or equal to 0.015% of P, less than or equal to 0.005% of S, 0.10-0.40% of Ni, 0.010-0.030% of Nb, 0.020-0.050% of V, 0.02-0.040% of Al and balance of Fe and unavoidable impurities, and the chemical composition of the steel is in accordance with the mixture ratio relation of 0.26% <= C+ 6Nb+ 4V<= 0.40%. The rolling technology comprises the steps of: adopting a continuous casting billet with the thickness of 260mm, and controlling the heating temperature of 1200-1250 DEG C, the heat preservation time of 4.0-4.5h and the tapping temperature of 1180-1220 DEG C; controlling the rolling by two stages, controlling the rough rolling screw-down rate per pass of 10-20% and the finish rolling temperature of 1000-1050 DEG C, and rough rolling the billet into an intermediate billet with 1.5-2.0 times of finished product thickness; controlling the start rolling temperature of precision rolling to be 850-900 DEG C, and the screw-down rate per pass of 8-12%; and adopting laminar flow cooling after rolling, controlling the finish cooling temperature to be 500-650 DEG C, the cooling speed of 5-10 DEG C/s, the high temperature off-line temperature to be 450-550 DEG C, and the time of cooling in heap of 60-72h. The invention adopts the casting billet with the thickness of 260mm for rolling, is low in equipment investment and excellent in low temperature impact toughness at -40 DEG C, does not need heat treatment, and has lower production cost.

Description

technical field [0001] The invention belongs to the technical field of extra-thick steel plate production, in particular to a 100mm-thick Q390E extra-thick steel plate and a manufacturing method thereof. Background technique [0002] With the rapid development of my country's national economy and the continuous increase of long-span structural projects, while the market demand for thick steel plates for machinery and construction is increasing, it also puts forward higher requirements for product specifications and performance. Thick steel plates are limited by factors such as the internal metallurgical quality of the continuous casting slab, the small compression ratio and the long heating interval of the slab, so the performance qualification rate is often difficult to guarantee. Therefore, currently only a few domestic steel mills have the ability to produce extra-thick steel plates with a thickness of 100mm, but the impact performance cannot be guaranteed. Moreover, in ...

AI Technical Summary

Problems solved by technology

In the prior art, the 260mm thick cast slab cannot be used to produce extra-thick steel plates with good low-temperature impact toughness

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