Optimization of straightening process of high strength and toughness steel plate

Release time：2019-12-31 Highstrengthductilesteelplateduetohighyieldstrength,inthecaseofthefinalrollingtemperature,thesteelplateispronetoladle,waveandotherproblems.Theanalysissuggeststhattherearetwofactors:oneisdistance.Becau...

　　High strength ductile steel plate due to high yield strength, in the case of the final rolling temperature, the steel plate is prone to ladle, wave and other problems.

　　The analysis suggests that there are two factors: one is distance. Because the final rolling temperature of high strength and toughness steel plate is 830-850℃, the distance between the fine straightener and the rolling mill causes the low straightening temperature of the steel plate and the difficulty of straightening the steel plate. The second is the reason of roller gap of straightener. Due to the slippage of the friction plate of the electromagnetic clutch, the roll gap is not correct, resulting in drift, and the adjustment of the pressure is not accurate, resulting in some steel plates produce the phenomenon of bending and other irregularities out of tolerance.

　　The optimization measures are as follows: carry out the high-pressure straightening technology, check and analyze the straightening pressure and straightening, optimize and improve the straightening press adjustment mode. Details as follows:

　　1. The steel plate adopts a large anti-bending ratio on the second and third rollers, and the pressure of each roll after the fourth stick gradually decreases, so that the rolled part can be straightened quickly. When the thickness of the steel plate is less than 20mm, the inclined straightening process is adopted. More than 20mm, using parallel straightening process.

　　2. Straightening path and straightening speed optimization. Considering the rapid cooling of thin steel plate and low straightening temperature, the rapid straightening process is adopted, and the precise straightening path is controlled at 3 times; More than 16mm steel plate, the steel plate temperature is relatively high, the use of slow straightening process, straightening the general control of 5 times. The irregularity is controlled within the range of 1-3mm.

　　3. Pressure reduction optimization for final pass. The middle wave of the original plate type increases the pressure of the final pass; Plate original plate edge wave, reduce the final pressure.

　　4. Improve the surface quality of steel plate straightening. 1) straightening high-strength steel plate, the cooling water on the lower surface of the front straightener is closed, and the cooling water of the rear straightener is reduced to improve the uniformity; 2) use the guide roller of straightener to reduce the influence of warped steel plate on the working roller surface; 3) optimize the replacement time of the straightening roller and monitor the production process to facilitate the straightening effect.

　　5 roll gap drift improvement. Remove the straightener roll gap electromagnetic clutch, use the rigid coupling, completely eliminate the friction caused by sliding roller gap.