Production method for reducing burning loss in Cr-Mo steel blank continuous furnace

Abstract

The invention discloses a production method for reducing burning loss in a Cr-Mo blank continuous heating furnace. The Cr-Mo steel alloy elements and the mass percentage meet the requirements of GB / T 713-2014. The method mainly comprises the steps of controlling the distances between a fuel spraying nozzle and an air nozzle in the furnace and a blank; controlling the lengths and the temperatures of a preheating section, a heating section and a soaking section in the continuous heating furnace; controlling the air-fuel ratio in the furnace to be 0.95-1.1, wherein the air-fuel ratio of the heating section is slightly larger than that of the soaking section; controlling the micro-positive pressure in the furnace, wherein the pressure is 0.3-0.5 MPa; and controlling the blank to enter the furnace while the blank is hot, wherein the temperature of the blank entering the furnace is 200-300 DEG C. According to a Cr-Mo steel plate produced through the method, the burning loss rate is controlled to be low during blank heating and is controlled to be 0.02-0.05%; the thickness of an iron sheet on the surface of the blank is small and is controlled to be 1-3 mm; and the surface quality of the rolled steel plate is good, and the grinding rate of the steel plate is 2-10%.

Description

technical field [0001] The invention belongs to the technical field of iron and steel metallurgy, and in particular relates to a production method for reducing burning loss in a continuous furnace of Cr-Mo steel billets. Background technique [0002] During the steel plate rolling process, the heating quality of the billet in the continuous furnace has a great influence on the internal and surface quality of the steel plate. If the billet is heated unevenly or the heating temperature is too low, the rolling reduction of the steel plate will be affected during subsequent rolling. Internal defects that cannot be pressed together will easily cause flaw detection failure of the steel plate. Insufficient heating will cause the alloy elements in the billet to be unable to fully dissolve, which will affect the phase transformation and precipitation of carbides during steel plate rolling, thereby affecting the performance stability of the steel plate; if the billet is in the furnace ...

AI Technical Summary

Problems solved by technology

[0002] During the steel plate rolling process, the heating quality of the billet in the continuous furnace has a great influence on the internal and surface quality of the steel plate. If the billet is heated unevenly or the heating temperature is too low, the rolling reduction of the steel plate will be affected during subsequent rolling. Internal defects that cannot be pressed together will easily cause flaw detection failure of the steel plate. Insufficient heating will cause the alloy elements in the billet to be unable to fully dissolve, which will affect the phase transformation and precipitation of carbides during steel plate rolling, thereby affecting the performance stability of the steel plate; if the billet is in the furnace for a long time If it is longer, it will not only cause a large energy consumption, but also cause serious burning of the billet, a large amount of iron sheet will be generated on the surface of the billet, and even overheating or overburning defects will occur, resulting in serious rolling defects.

[0003] Since the Cr-Mo steel billet contains more alloying elements such as Cr, Mo, V, etc., the alloying elements will reduce the melting point of the steel, and the low melting point of the steel will significantly increase the difficulty of heating the billet. First, the low melting point makes the billet easy to burn. Secondly, the heating temperature window of the billet is narrow, the heating temperature is high, and over-burning defects are easy to occur, the heating temperature is low, the steel plate rolling is difficult, and the continuous furnace has a large volume, which makes it more difficult to ensure the stability of the furnace temperature

[0004] Due to the high price of Cr-Mo steel, if the billet is severely burned, the effective unit weight of the billet will be reduced due to burning, resulting in economic losses; secondly, the iron sheet is easily pressed into the phenomenon during rolling, which affects the surface quality of the steel plate, and the poor surface quality increases the grinding process , time-consuming and labor-intensive, increasing production costs; and a large amount of iron sheet generated by heating the billet requires frequent cleaning of the iron sheet in the trench under the rolling mill, which affects the smooth production