CN-117299821-B - Identification and control method for scratch defects of cold-rolled high-strength steel

Abstract

The invention relates to a method for identifying and controlling scratch defects of cold-rolled high-strength steel, and belongs to the technical field of metallurgical control methods. The technical scheme of the invention is that the method for counting and identifying the morphological characteristics of scratches in different continuous annealing processes of continuous casting, hot rolling and acid rolling and the corresponding process control scheme are used for comprehensively controlling key control points in the production process of each process. The invention has the beneficial effects that the scratch defect of the finished product of the terminal is effectively controlled by providing the morphological characteristics and the identification methods of scratches in different procedures and the control scheme of scratches in different procedures, the quality level of the product is improved, the quality loss is reduced, and the contract redemption rate is improved.

Inventors

• CHEN ZHITONG
• ZHANG ZHIHONG
• YIN QIAN
• SHI WEIPING
• LIU YONGQIANG
• YUAN BO
• CHEN FULAN

Assignees

• 邯郸钢铁集团有限责任公司
• 河钢股份有限公司邯郸分公司

Dates

Publication Date

20260505

Application Date

20230918

Claims (2)

1. 1. The method for identifying and controlling the scratch defects of the cold-rolled high-strength steel is characterized by comprising the following steps of: (1) The method comprises the steps of identifying the scratch defects of the cold-rolled high-strength steel, wherein the identification rule is that the continuous casting scratch is in a black or yellow brown line shape, the hot rolling scratch is a white line defect with slight hand feeling or no hand feeling, is thicker, is distributed in a single way or in clusters and is mainly distributed at the head and tail parts of strip steel, the acid rolling scratch is a thinner white line, and can be distributed in the strip or at the head and tail parts; (2) In the continuous casting process, checking the conditions of the rollers and the bearings of the sector section, repairing the sunk rollers and abnormal bearings, ensuring the normal operation of the sunk rollers and abnormal bearings, cleaning the rollers, and avoiding abnormal rotation and adhesion of oxide scale foreign matters; (3) In the hot rolling process, the height of a finish rolling inlet transition cross beam is matched with the height of a pinch roll under an outlet of a descaler before finish rolling, the height of one side of a finish rolling F7 outlet guide table is matched with an outlet roller table, the normal rotation of a layer cooling roller table is checked and ensured, a coiling pinch roll is polished before production to ensure the roll surface quality, the clamping force of the coiling side guide plate is controlled when the coiling side guide plate is cleaned, the elevation of the finish rolling inlet transition cross beam is 20mm or more than that of the pinch roll under the outlet of the descaler before finish rolling, the elevation of one side of the finish rolling F7 outlet is 20mm less than that of the outlet roller table, and the clamping force of the coiling side guide plate is controlled to be 50KN or less when the coiling side guide plate is cleaned, so that the abrasion of the coiling side guide plate is reduced; (4) Checking the rotation condition of a roller system, recovering an abnormal roller which does not rotate, regularly supplementing oil lubrication to a bearing, ensuring stable concentration of emulsion and controlling the roughness of the roller; (5) In the continuous annealing process, the damaged roller surface is polished or replaced, the normal rotation of the brush roller support roller is checked and ensured, the enough tension of the strip steel is ensured, the furnace Duan Zhangli is controlled at 6-7Mpa, the roughness is ensured by periodically replacing the leveling roller, the loop tension is kept at 18-22Mpa, and the circle shear Duan Zhangli is kept at 25-30Mpa.
2. 2. The method for identifying and controlling the scratch defects of the cold-rolled high-strength steel according to claim 1, wherein in the step (4), the concentration of the emulsion is 1.5-3.0% of a 1-4 stand, 0.3-1.0% of a 5 stand, the roughness of the roller is controlled to be less than 1.0 mu m, and the 5 stand is kept to be 2.5-3 mu m.

Description

Identification and control method for scratch defects of cold-rolled high-strength steel Technical Field The invention relates to a method for identifying and controlling scratch defects of cold-rolled high-strength steel, and belongs to the technical field of metallurgical control methods. Background With the deep promotion of 'carbon reaching peak, carbon neutralization' national strategy, the automobile manufacturing industry as an important economic support column has important historical mission in the course of energy conservation and emission reduction. The trend in automobile weight reduction necessarily requires more and more advanced high-strength steel to be put into use. In advanced high-strength steel, due to the superior comprehensive properties of low yield ratio, high elongation, high work hardening index and the like, the application proportion of the dual-phase steel is higher and higher under the dual drive of automobile weight reduction and safety, and the application proportion of the dual-phase steel on C-grade automobiles is up to 74 percent according to statistics, so that the market demand is larger. The cold-rolled dual-phase steel relates to a plurality of production procedures, the flow is longer, and the surface defects are various, wherein scratch defects are often unavoidable, and are one of the main surface defect types. The steel making, hot rolling, cold rolling and continuous annealing all cause scratch. The Chinese patent application No. CN202010618379 proposes a production method of a cold rolling continuous annealing wide web for improving the short line scratch defect, wherein the thickness of a cold rolling finished product is 1.0-2.0 mm, the thickness of a hot rolling incoming material is 5.0-6.0 mm, convexity is controlled to be 40-50 mu m, the total reduction rate of acid rolling is 65-80%, the adjustment of uneven plate shape adopts symmetrical adjustment, single side rib waves are adjusted to double side rib waves or middle rib waves by deflection and a roll bending, the uneven degree is controlled to be less than or equal to 10I, the tension difference between the transmission side and the operation side in a continuous annealing process is controlled to be less than or equal to 10%, the hydrogen atmosphere content in the furnace is controlled to be 5-10%, the dew point in a heating area is controlled to be less than or equal to-30 ℃, and the longitudinal and transverse short line scratch defect is improved by adjusting the plate shape, the deflection and the roughness of the roll surface of the cold rolling continuous annealing wide web. The invention patent with the patent application number of CN202211052357 proposes a method for preventing the cold-rolled sheet from being scratched by stopping an annealing furnace area of a continuous annealing furnace abnormally, controlling the heat preservation temperature according to the thickness of the cold-rolled sheet after stopping the annealing furnace area of the continuous annealing furnace, stopping the annealing furnace area of the continuous annealing furnace simultaneously to reduce the set value of each section of tension to 2-3 kN, stopping the annealing furnace area of the continuous annealing furnace for more than 30 minutes, setting the annealing furnace area on a secondary HMI as the lost tension, simultaneously manually opening a compensation roller pin lock of an inlet and an outlet of the annealing furnace area, horizontally moving the compensation roller to compensate the shrinkage of the cold-rolled sheet length, and further compensating the shrinkage of the cold-rolled sheet length if the tension of the annealing furnace area still exceeds 50% of the set value after manually opening the compensation roller pin lock, and further compensating the shrinkage of the inlet and the outlet looper at a local operating table. The prior art is used for carrying out improved control on scratches in a single process, and no process identification method for generating scratches exists, but scratches in each process of steelmaking, hot rolling and acid rolling can be inherited to a terminal continuous annealing process, so that the research on a set of scratch identification and control methods suitable for cold-rolled high-strength steel is particularly important. Disclosure of Invention The invention aims to provide a method for identifying and controlling scratch defects of cold-rolled high-strength steel, which effectively controls the scratch defects of a finished product of a terminal, improves the quality level of the product, reduces the quality loss, improves the contract redemption rate and effectively solves the problems in the background art by providing morphological characteristics and identification methods of scratch in different procedures and a control scheme of scratch in different procedures. The technical scheme of the invention is that the method for identifying and controlling the scratc