A kind of low-alloy high-strength steel plate for large-thickness boiler drum and its manufacturing method

Abstract

The invention relates to a low-alloy high-strength steel plate for a big-thickness boiler drum and a manufacturing method of the low-alloy high-strength steel plate. The manufacturing method comprises the following steps: (1) carrying out smelting, external refining and vacuum degassing treatment on the following components in percentage by weight: 0.135-0.17% of C, 0.15-0.50% of Si, 1.20-1.60% of Mn, less than or equal to 0.010% of P, less than or equal to 0.002% of S, 0.10-0.30% of Cr, 0.10-0.30% of Mo, 0.40-0.70% of Ni, 0.008-0.018% of Nb, 0.020-0.040% of Al, less than or equal to 0.05% of Cu, less than or equal to 0.006% of N, less than or equal to 0.003% of O, less than or equal to 0.00018% of H, 0.004-0.010% of Ti and the balance of Fe and unavoidable impurities, wherein Ti / N is less than or equal to 2.74; (2) casting; (3) carrying out steel ingot and cogging; (4) carrying out steel plate rolling and finishing; (5) carrying out normalizing, wherein the normalizing temperature of the steel plate is 900-940 DEG C, the temperature maintaining time is not less than 30 minutes after a core part of the steel plate is heated to 900-940 DEG C; (6) carrying out accelerated cooling to guarantee the cooling speed of the core part of the steel plate to be not less than 1 DEG C / second; (7) tempering at the temperature of 640-690 DEG C, and carrying out air cooling until reaching the room temperature after the steel plate is discharged out of a furnace.

Description

technical field [0001] The invention relates to a steel plate for a boiler drum and a manufacturing method thereof, in particular to a low-alloy high-strength steel plate for a large-thickness boiler drum and a manufacturing method thereof. 100mm~150mm. Background technique [0002] The overall structure of the boiler includes two parts: the boiler body and auxiliary equipment. The furnace, drum, burner, water wall superheater, economizer, air preheater, frame and furnace wall and other main components in the boiler constitute the core part of steam production, which is called the boiler body. The two most important components in the boiler body are the furnace and the drum. Among them, the main functions of the drum are: (1) connecting the heating surface pipes and pipelines, and installing water supply pipes and water vapor partitions inside the drum to form a stable water cycle; (2) designing a steam-water separation device inside the drum to Get dry and clean protecti...

AI Technical Summary

Problems solved by technology

In addition, in this invention, the steel plate is directly put into the water tank to accelerate cooling after normalizing. This method is inconvenient to control the cooling rate, and the steel plate is prone to produce abnormal structures, resulting in substandard performance.

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