Pickling line tandem cold mill withdrawal and straightening machine control method

Abstract

The invention discloses a pickling line tandem cold mill withdrawal and straightening machine control method. When the yielding strength of a target steel grade is smaller than or equal to 300 MPa, the ductility of a withdrawal and straightening machine is 2.3%-2.5%, and the engagement amount is 30 mm to 35 mm; when 300 MPa<the yielding strength<=450 MPa, the ductility is 1.8%-2.2%, and the engagement amount is 35 mm to 40 mm; when the yielding strength is larger than 450MPa, the ductility is set 0.5%-1.2%, and the engagement amount is 40 mm to 42 mm; and meanwhile according to the difference of the thickness or the width of front strip steel and rear strip steel, weld joint excessive withdrawal and straightening machine modes are divided into four kinds. By means of the pickling line tandem cold mill withdrawal and straightening machine control method, the withdrawal and straightening machine achieves automatic grouping control over steel grades in different yielding strength levels, normal withdrawal and straightening of the withdrawal and straightening machine can be guaranteed, the loads of the withdrawal and straightening machine can also be effectively reduced, normal pickling of the strip steel is guaranteed, and the withdrawal and straightening up-to-standard rate reaches 98% or above; and selection of the weld joint excessive withdrawal and straightening machine modes guarantees normal pickling of weld joint heads and tails, and the strip breakage accident caused by poor weld joint quality is avoided.

Description

technical field [0001] The invention relates to a control method for a tension-leveler of an acid rolling mill, and belongs to the technical field of hot-rolled strip steel tension-leveler control technology. Background technique [0002] The pickling rolling unit is a combined pickling and cold rolling unit. Pickling is the first treatment process of cold rolling. Its main function is to remove the iron oxide layer adhering to the steel surface, prepare for subsequent processing, and prevent New defects appear during washing. The tension-leveler is located before the pickling section, and is used for tension-leveling the hot-rolled strip steel, breaking the scale of the strip steel, and ensuring that the strip steel can be fully pickled, which plays a decisive role in the pickling effect. The tension leveler is composed of two sets of bending units and one set of straightening units. By setting a certain elongation and engagement amount of the tension leveler, the tension ...

AI Technical Summary

Problems solved by technology

When setting the parameters of the tension leveler, due to the frequent changes of the steel grade and specification of the strip steel, the operator needs to frequently change the parameters of the tension leveler according to the operating experience. Sudden mutations and parking accidents will also cause damage to the synchronous shaft of the tension leveler, and the tension leveler compliance rate of the tension leveler is less than 80%. The cupping test failed) or the deviation of the width and thickness of the front and rear strips is large, and the accident of weld cracking and broken strips is prone to occur when the weld passes through the tension leveler, which seriously affects the running speed of the production line and causes major economic losses