Fine crystal strengthen carbon constructional steel and manufacture process for hot-rolling thin slab thereof

Abstract

The invention relates to a manufacture process of carbon steel and carbon steel hot rolling plate, in particular to a manufacture process of fine grain reinforcement carbon structural steel and hot rolling sheet plate of the steel. The invention mainly solves the technical problem that hot rolling plate of higher strength can not be produced on common completely continuous hot continuous rolling mill by use of common carbon structural steel at present. The fine grain reinforcement carbon structural steel adopts the following chemical composition (weight percent): 0.14 percent to 0.20 percent of C, 0.10 percent to 0.40 percent of Si, 0.65 percent to 0.90 percent of Mn, less than or equal to 0.025 percent of P, less than or equal to 0.015 percent of S and the rest, Fe. The manufacture process of the hot rolling sheet plate is as follows: a continuous casting slab which meets the requirements of compositions is heated to 1,210 DEG C to 1,250 DEG C; a rough rolling stage comprises five-pass tandem rolling and the end temperature of the rough rolling stage is between 1,050 DEG C and 1,060 DEG C; in addition, the thickness of an intermediate slab ranges from 35 mm to 45 mm. When rough rolling is finished, the intermediate slab is curled through a hot coil box and then is unfolded for finish rolling; a finish rolling stage comprises six-pass tandem rolling with the start rolling temperature ranging between 920 DEG C and 940 DEG C and the end temperature ranging between 820 DEG C and 860 DEG C; after finish rolling, the thickness of a steel plate is between 2 mm to 8 mm; in addition, a laminar flow cooling stage adopts forepart intensive cooling with the coiling temperature ranging from 520 DEG C to 620 DEG C.

Description

Technical field: [0001] The invention relates to a carbon steel and its hot-rolled plate manufacturing process, in particular to a fine-grain strengthened carbon structural steel and its hot-rolled thin plate manufacturing process. Background technique: [0002] In order to achieve the sustainable development of society, steel materials should have good performance-price ratio, good strength and toughness, and reduce energy and resource consumption. R el =200~400MPa. The strengthening methods include solid solution strengthening, dislocation strengthening, precipitation strengthening, etc., but only fine-grain strengthening can increase the strength while improving the toughness or keeping the toughness basically unchanged. Therefore, fine-grain strengthening technology is an important way to study and improve the strength and toughness of steel materials. At present, the grain size of carbon structure hot-rolled steel sheets produced on industrial hot rolling mills reach...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a kind of fine-grain strengthened carbon structural steel and its hot-rolled sheet manufacturing process that can realize industrial batch production on the existing ordinary full continuous hot rolling mill, and mainly solve the problem of using ordinary carbon structure at present. Due to the technical problem that the steel composition cannot produce higher-strength hot-rolled plates on ordinary full-continuous hot-rolling mills, the present invention provides fine-grain strengthened carbon structural steel plates with excellent low-temperature impact toughness

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