A kind of heating method of copper-containing low-alloy steel

Abstract

The invention discloses a heating method for copper-bearing low-alloy steel. The heating method comprises the steps that a plate blank is heated through fuel gas with the heat value being 2,200-2,300 Kcal / Nm<3> for 140-160 minutes after being put into a furnace, wherein the maximum outlet temperature at the end of the first heating stage is controlled not exceeding 1,070 DEG C; after entering the second heating stage, the furnace quickly heats up for 40-50 minutes, wherein the maximum outlet temperature at the end of the second heating stage is controlled to be 25 DEG C-30 DEG C lower than the tapping target temperature; at the even heating stage, the temperature is kept for 25-30 minutes or so, and the tapping temperature range of the plate blank is 1,220 DEG C-1,300 DEG C. According to the heating method, melting of a copper-rich layer grain boundary is suppressed, and the beneficiation quantity of copper is reduced; in this way, when a normal rough rolling procedure is performed on the plate blank, copper beneficiating underneath sheet iron is easy to remove, and therefore the defect of copper brittleness is overcome.

Description

technical field [0001] The present application relates to the technical field of steel rolling, in particular to a heating method for copper-containing low-alloy steel. Background technique [0002] When the Cu-containing steel is heated, the oxidizing atmosphere in the furnace selectively oxidizes Fe instead of Cu, so that Cu is enriched at the interface between the oxide scale and the steel matrix. When the temperature in the furnace reaches above 1080°C, the copper-rich (i.e., enriched copper) phase penetrates into the austenite grain boundary, resulting in intergranular cracking on the surface of the steel during rolling, and the phenomenon of "copper brittleness". [0003] In order to prevent the occurrence of "copper embrittlement", the current technology mainly considers from the aspects of limiting the time of the slab in the furnace, reducing the tapping temperature of the slab, and increasing the rough rolling and descaling passes. For example, in order to prevent...

AI Technical Summary

Problems solved by technology

For the control of heating temperature, the control of suitable heating atmosphere is not considered, but only the control of heating temperature is emphasized, and the heat preservation needs to be carried out at 1000℃~1050℃ for 30~60min. Too long time will cause the rolling mill to stop production and wait, affecting the output

Control the slab soaking time in the range of 40-50Min, the total time in the furnace should not be higher than 180Min, do not allow the slab to be kept in the furnace for a long time to be rolled, and limit the maximum temperature of the slab to 1280°C, which will affect the actual production Brings various restrictions and puts too high demands on the production organization

[0005] In summary, the above methods will have various deficiencies, and none of them is a relatively perfect method to solve the phenomenon of "copper brittleness"

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