Mo-containing steel plate being high in high-temperature strength and good in low-temperature impact toughness, and manufacturing method thereof

Abstract

The invention relates to a Mo-containing steel plate being high in high-temperature strength and good in low-temperature impact toughness. The steel plate comprises the following chemical components in percentage by mass: 0.14-0.18% of C, 0.25-0.35% of Si, 0.75-0.85% of Mn, 0.25-0.35% of Mo, 0.02-0.05% of Al, no more than 0.012% of P, no more than 0.05% of S, no more than 0.20% of Cu, no more than 0.20% of Cr, 0.20-0.30% of Ni, 0.010-0.020% of Nb and / or 0.010-0.025% of Ti, and the balance of Fe and inevitable impurities, wherein the following carbon equivalent (Ceq) formula is met: Ceq = [C + Mn] / 6 + (Cr + Mo + V) / 5 + (Ni + Cu) / 15]*100%, that is, the Ceq ranges between 0.36 and 0.40. A technological manufacturing process of the steel plate comprises the following steps: blowing in a converter; LF refining; vacuum degassing; continuous casting; primary slow cooling; heating; rolling; cooling control; secondary slow cooling; heat treatment; fine inspection; flaw detection; performance examination; and packaging and warehousing. The steel plate provided by the invention is relatively high in high-temperature strength; meanwhile, the low-temperature impact toughness is relatively good, the Ceq is relatively low and the welding performance is good; and the steel plate adopts a ferrite-pearlite structure, and is delivered in the normalized state.

Description

technical field [0001] The invention belongs to the technical field of metallurgical steel plates, and in particular relates to a Mo-containing steel plate with high strength under high-temperature environment and excellent low-temperature impact toughness and a manufacturing method thereof. Background technique [0002] Alloy steel plate containing Mo, delivered in normalized state, mainly used in pressure vessels, steam turbines, metallurgical machinery and other fields, compared with other common C-Mn steel materials, its applicable temperature range is wider, especially the high temperature adaptability is wider; Compared with conventional Cr-Mo steel, it has the advantages of easy production, short delivery time, low cost and wide application fields; compared with quenched and tempered steel plate, it saves more energy in the production process of normalized steel plate material, and the performance of steel plate after welding is more stable . [0003] At present, equ...

AI Technical Summary

Problems solved by technology

[0004] For the steel plate operated at high temperature, the presence of Mo is beneficial to improve and stabilize the high temperature performance of the steel plate, so that the steel plate still has high strength under high temperature conditions, especially the creep resistance performance, but a certain Mo content is harmful to the low temperature of the steel plate. The impact performance is extremely unfavorable, which seriously deteriorates the low-temperature impact toughness of the steel plate, and the two are contradictory

Theoretically, the low temperature toughness can be improved by adding functional alloys, but the addition of alloys will cause the carbon equivalent of the steel to be too high, which will affect the weldability of the steel plate

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