Rolling Time, Clearance Time, Cycle Time and Rolling Rhythm
The production process of steel pipes needs to be heated, plastically deformed, and cooled. The controlled rolling process of hot rolling mainly uses rolling mill to make the heated steel bar or steel plate become regular in size, roundness, and wall thickness to meet the process requirements and technical requirements.
The performance of the rolling mill and the production process have a great relationship with the rolling time, clearance time, cycle time and rolling rhythm. In the process of hot rolling, the rolling time mainly includes the time of deformation of the workpiece, the time between rolls, the time of operation of the roll roll and the entire blanking time.
Rolling time can be divided into three types: reverse rolling time, forward rolling time, and total rolling time. The rolling time is the time required for the workpiece to complete the entire rolling process in the rolling mill. During the rolling process, the forward rolling time is the time required for the material to move forward in the length direction from the entry port of the rolling mill. The backward rolling time is the time needed for the workpiece to pass through the width direction from the exit port of the rolling mill. The total rolling time of the operation is the sum of the total forward rolling time and reverse rolling time.
The during rolling time is related to the pre-forming time. The pre-forming time is the time required for the blank to move into the length required prior to entering the rolling mill. The pre-forming time affects the entering length of the workpiece and affects the size and quality of the rolled material. Ultimately, the total rolling time of the workpiece will increase.
The clearance time. The clearance time is the time that the rolls do not turn, but the workpiece continues to move through the support system from the entrance to the exit of the rolling mill. The clearance time is the time when the workpiece needs to move in the support of the rolling mill. The clearance time is generally shorter than the rolling time.
The cycle time is the total time it takes for a single rolling stand to process a certain amount of billets or semi-finished products. With the cycle time of the rolling stand, it is possible to accurately calculate the number of rolling stands that can be processed in a unit of time.
The rolling rhythm is the control method used to change the rolling time, clearance time, and cycle time of the rolling mill constantly and dynamically. It is based on the dynamic adjustment of the opening and closing speed of the rolling mills lifting and lifting device, the spindle speed, the diameter of the roll, etc., to adapt to changes in the process to achieve the best effect.
In additional, during the rolling process, the rolling process must be dynamically adjusted by the use of rolling rhythm. This technique can be used to improve the control of the rolling speed to prevent the uneven erosion of the rolling surface of the roller and changes in the diameter of the roller, as well as reduce the breakage of the rolled material caused by the aging of the roller. The rolling rhythm can be used to improve the flow of the material in the rolled section by controlling the total rolling time and cycle time.
In summary, the rolling time, clearance time, cycle time and the rolling rhythm are important performance indicators for the hot rolling process. By adjusting these indicators, it is possible to effectively improve the production efficiency of the hot rolling mill while ensuring the quality of rolled products.
