Control process for single-stand Steckel mill to produce special-purpose pipeline steel

Abstract

The invention relates to a control process for a single-stand Steckel mill to produce special-purpose pipeline steel, which has the following requirements: the tapping temperature of a heating furnace is equal to or higher than 1150 DEG C, the second-stage bloom rolling temperature is lower than or equal to 900 DEG C, the thickness of temperature-holding billets is smaller than or equal to 3.3h, the finish rolling temperature ranges from 780 DEG C to 820 DEG C, nine or eleven rolling passes are required, the reduction rate of the last but one pass is equal to or larger than 9% or equal to or smaller than 13%, the reduction rate of the last pass is 0%, the finish rolling speed at the last but one pass V is equal to or larger than 1.45m / s or is equal to or smaller than 1.75m / s, the secondary rolling coefficient is selected according to conditions of plate shapes, roll body cooling water is turned on according to conditions of rolling cycle, abrasion of working rolls and heat expansion, rolled workpieces are required to swing on a roll bed in front of a straightening machine before entering a cooling system, and a gap between an inlet of the straightening machine and an outlet roll is set according to the requirement that plastic deformation of the rolled workpieces is equal to or larger than 80% at least in the thickness direction before the rolled workpieces enters the straightening machine. The control process not only can meet requirements for finish rolling temperature, entry temperature and re-reddening temperature but is combined with rolling and straightening processes, controls performance and plate forms comprehensively, and particularly realizes comprehensive control in hot rolling and flat rolling of the single-stand Steckel mill to performance and plate forms of special-purpose pipeline steel.

Description

technical field [0001] The invention relates to a shape control technology for pipeline steel plates, in particular to a control technology for producing special-purpose pipeline steel by a single-stand furnace coil rolling mill. Background technique [0002] At present, when using blanks with a thickness of 220mm, 180mm, and 150mm to flat-roll special-purpose pipeline steel, both performance and shape need to be controlled. In order to ensure the performance, there are extremely strict and accurate requirements on the final rolling temperature, water entry temperature and red return temperature. For example, for large deformation resistant pipeline steel X70HD, the final rolling temperature of the penultimate pass is 780°C-820°C to avoid mixed crystal rolling caused by ferrite precipitation; in order to ensure the steel plate has the ability to resist large deformation, it is necessary to The temperature before the rolling mill is controlled between 695°C and 740°C to obta...

AI Technical Summary

Problems solved by technology

Because the length of the original billet used is more than 7m, no matter how to increase the heating temperature or rolling speed, etc., because the rolled piece is too long in the finishing rolling stage, the rolling process will become thinner and thinner with the rolling process of the steel plate, and the steel plate will be thinner and thinner. The temperature drop will become faster and faster, resulting in extremely uneven temperature distribution along the length of the rolled piece, which increases the difficulty of controlling the shape and performance of the rolled piece

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