Production process of low compression ratio thick container plate

Abstract

The invention relates to the field of manufacturing of steel for a low-alloy high-strength pressure vessel, in particular to a low-compression-ratio extremely thick vessel plate production process. The production process comprises the steps of smelting, continuous casting, heating, rolling and heat treating, wherein impurities and harmful elements such as P, S, O, N and H are controlled in the smelting process; the center segregation of a casting blank is not more than C type 1.5, and the loosening of the casting blank is not more than 0.5 in the continuous casting process; the heating temperature is 1175-1215 DEG C in the heating process; the rolling is divided into a coarse rolling stage and a fine rolling stage, the coarse rolling stage adopts high-temperature hot-rolling in a temperature interval of 1150-1030 DEG C and with the deformation of 44%, the single-pass reduction of the coarse rolling is 20-40 mm, the fine rolling adopts non-recrystallization zone temperature-control rolling in a temperature interval of 930-860 DEG C and with the deformation of 28.6%, the single-pass reduction of the fine rolling is 5-15 mm, and a stack is slowly cooled to below 200 DEG C after rolling; the normalizing is at 890 DEG C, and the time in furnace is 1.5min / mm. The production process breaks through the limitation that a traditional process of rolling a steel plate from a continuous casting blank requires a compression ratio of three times and more, and a thick steel plate with guaranteed crack detection and guaranteed cost can be rolled by taking a normal continuous casting blank as a raw material.

Description

technical field [0001] The invention relates to the field of manufacturing steel for low-alloy high-strength pressure vessels, in particular to a production process for low-compression-bit-thick vessel plates. Background technique [0002] The boiler and pressure vessel industry requires extra-thick vessel plates over 80mm in the manufacture of large-scale boilers and vessels. Due to the high temperature and high pressure in the application occasions, and even carrying corrosive media, the safety requirements are very high, and the extra-thick vessel plates generally require flaw detection delivery. , and there is a wall thickness effect that the strength gradually decreases with the increase of thickness, so the production is very difficult. Traditionally, in order to ensure the final performance of the steel plate, the compression ratio is generally more than 5-7 times, and the limit is 3 times. Only electroslag remelting, a high energy-consuming process, can relax the com...

AI Technical Summary

Problems solved by technology

Due to the limited capacity of continuous casting machines to produce continuous casting billets, domestic general continuous casting machines are all below 300mm. In this way, large-thickness steel ingots are required to be rolled to produce extra-thick plates above 100mm. Because the steel ingots adopt die-casting technology, the production efficiency is low and the yield is low. Low, serious environmental pollution

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