Brief Introduction of Cutting Head Flying Shear Used in Packaging Steel Strip Production Rolling

Brief Introduction of Cutting Head Flying Shear Used in Packaging Steel Strip Production Rolling
　　The cutting head flying shear is located on the exit side of the rough rolling mill, in front of the finishing rolling descaler box. Its function is to cut off the low temperature and poorly shaped head and tail ends of the intermediate strip that enters the finishing mill, so that the strip can smoothly pass through the finishing mill and the output roller table to the coiler to prevent jamming during the threading process. Steel and low temperature head and tail produce roll marks on the surface of the roll.
　　The cutting head flying shears of hot strip mills generally use drum flying shears, and a few adopt crank flying shears. Drum flying shears are divided into three forms: single-side transmission, double-side transmission and asynchronous shearing. Their main advantage is that the structure is relatively simple. Two pairs of cutting blades of different shapes can be installed at the same time to cut the head and the tail respectively. . The main advantage of the crank-type flying shear is that the cutting blade cuts vertically, and the shear thickness range is large, up to 80mm. The disadvantage is that only a pair of straight blade shears can be installed.
　　 The structure of the rotating drum flying shear is constantly improving. The first rotating drum flying shear is a single-sided transmission. At that time, the thickness of the intermediate billet was small, the material was soft, and the cutting effect was better. With the continuous increase in the thickness of the intermediate belt blanks and the increase in material strength, the unilateral transmission shearing appears to be distorted and the shear quality is not good. For this reason, gear transmissions are used on both sides of the drum to reduce the shear Distortion improves the cutting quality. Asynchronous shearing means that the linear speeds of the upper and lower drum blades are inconsistent, and the upper blade has a faster linear speed than the lower blade. The method to achieve asynchronous shear is that the diameter of the upper drum is greater than the diameter of the lower drum by about 5.6%, and the angular velocity of the two drums is the same, forming asynchronous shear. The main advantage of this cutting method is that the quality of the cutting section is good, and the thickness of the cutting strip can be increased to 60mm, which avoids the accident of continuous cutting due to the wear of the cutting blade and the increase of the cutting blade gap. Because the shear blade gap of the general shearing machine does not change during the cutting process, it is a fixed value, while the shear blade gap of asynchronous shear changes, from a positive gap to zero, and then a negative gap, so it avoids Cut the constant situation.
　　 The cutting flying shears for hot strip mills currently produced in my country are all drum flying shears except Baosteel’s 2050mm crank-type flying shears. Among them, Baosteel’s 1580mm and Anshan Iron and Steel’s 1780mm mills’ cutting flying shears are Drum asynchronous cutting flying shears.