Flying shear is generally based on the section of the mill and unit layout to choose, for the semi-continuous rolling line in the roughing mill after the choice of fixed shear, for continuous rolling line generally choose flying shear, in the continuous rolling off the head area can also choose fixed shear.
For bar flying shear is mainly based on the shear section to choose, flying shear shear section requirements are as follows.
Pendulum shear: ≥ Φ80mm, V ≤ 2m / s.
Crank shear: ≥ Φ40mm, V ≤ 4 ~ 3.5m / s.
Combination shear: Φ10 ~ 80mm, V ≤ 16 ~ 18m / s.
Rotary shear: Φ10 ~ 40mm, V ≤ 16 ~ 18m / s.
Online diameter measurement
Generally, the online diameter measurement of rolling line is open-loop, only monitoring role.
Sizing
Alloy steel bars are generally sawed to improve the end quality of the sizing products, but small size (Φ10~40mm) products can also be sheared for sizing to meet user requirements and improve production. Alloy steel bars are generally divided into hot sizing and cold sizing according to the sizing temperature. The hot sizing is done by hacksaw and the cold sizing is done by abrasive wheel saw. Steel sawing cost is low, noise is big, sawing products generally with burrs need to chamfering treatment; Abrasive wheel sawing cost is high with smoke and dust need to dust, sawing products end quality is good.
Cooling
Alloy steel bars in the combined work, spring, high work, ball bearings, stainless steel and other need slow cooling steel in the cooling process requires the cooling bed temperature ≥ 700 ℃, in order to meet the installation of slow cooling pit or slow cooling box requirements. This requires the cold bed in accordance with the requirements of production can meet both the general cooling under the cold bed requirements, but also to be able to meet the slow cooling material quickly through the next line requirements.
According to the product specifications of large bars and small bars in the cooling selection is also different, because of the large bar specifications, fast moving steel devices can move a large weight, to meet the pace of production, and low cooling speed. Therefore, the general large bar cooling bed with a multi-functional cooling bed with fast steel transfer device to ensure that the slow-cooling material quickly under the cooling bed, small specifications due to the small specifications of the bar cooling fast and must be in rows under the cooling bed, so the small bar cooling bed side of the fast conveyor chain to meet the requirements of slow-cooling material down the line.
In order to avoid the confusion of steel numbers, the bars are marked on the end of the bars, but the small size bars cannot be marked online at present (<Φ80mm products). Large bars can be marked online on the cold bed. At present, domestic marking is divided into: manual marking and mechanical marking, and mechanical marking can be divided into one-time stamping type, word-by-word stamping type, needle type, and high-energy plasma marking. Among them, high-energy plasma marking is non-contact marking, not affected by temperature. Contact marking is affected by temperature, the temperature is too high, the whole character will be sunken in, the temperature is too low and the stamping will not be clear, according to the experience of the production plant is generally about 800 ℃ is more ideal. According to the bar product specifications can choose different marking equipment, contact marking the smallest word up to 8 mm, non-contact marking word height of 18 mm minimum.
Post time: Oct-11-2022