What is pass line in rolling mills?
It is of course well known that the pass-line of a rolling mill is the path of movement of sheet metal through the mill between the working rolls thereof.
How is rolling mill torque calculated?
The torque is obtained by integrating the frictional force multiplied by roll radius over the arc of contact (lagging and leading zones). The negative sign before the second term is due to the fact that in leading zone the metal moves faster than the rolls hence it helps to rotate the rolls.
What is angle of bite in rolling?
In rolling metals where all the force is transmitted through the rolls, maximum attainable angle between roll radius at the first contact and the roll centers. If the operating angle is less, it is called the contact angle or roll angle. Ref: ASM, 1.
Which type of force is applied in rolling operation?
Rolling is the process of reducing the thickness or changing the cross section of a long workpiece by compressive forces applied through a set of rolls, as shown in figure (5-1).
How do you calculate the bite angle of a roll?
How to Calculate Bite Angle? Bite Angle calculator uses bite_angle = acos(1-(Height/(2*Radius))) to calculate the Bite Angle, Bite Angle in rolling metals is where all the force is transmitted through the rolls, maximum attainable angle between roll radius at the first contact and the roll centers.
What happens when bite angle is greater than friction angle?
Rolls will bite a workpiece when the angle of friction is greater than the angle of bite. Initially if strip is made to enter rolls by tapering the front end of strip, then angle of bite can be increased two times (angle of nip).
What is neutral point in rolling process?
At one point along the contact surface of the roll and work, the surface velocity of the roll will be equal to the velocity of the work. This point is referred to as “Neutral point” or “No Slip Point”.
Why is there a neutral point in the force analysis for rolling?
Neutral point. It is known as neutral point, or no slip point to the left of the neutral point, roll moves faster than the workpiece, and to right the workpiece moves faster than the roll.
What is a rolling calculation?
About Rolling Calculations Rolling calculations are a means of applying a metric over a set of data points composed of multiple periods. Options include rolling averages and rolling metrics. As opposed to rolling averages, it uses all the data to produce a new calculated metric.
What is R factor in rolling mill?
revolving rolls where the incoming height is greater. than the exiting height the change in Area of the two shapes is referred to as the reduction. □ R-Factor = Area in vs. Area out. □ R-Factor = Ain/Aout.
In which rolling condition higher reduction is possible?
For greater reduction, more frictional force is required, and because it is not available, the rolls start slipping over the strip. Thus it is that maximum possible reduction is achieved when the neutral point is at the exit, that is, when the exit velocity is equal to the circumferential roll velocity.
What is maximum draft in rolling?
The maximum change in plate thickness that can be achieved in a single pass is given by: , where is the coefficient of friction between the rollers and the plate, is the roll diameter, is the original plate thickness, is the final plate thickness, and is the maximum draft.
How do you reduce roll force in a rolling process?
Roll force, torque and power requirement Reducing roll force Roll forces can be reduced by the following means: – Reducing friction at the roll-workpiece interface – Using smaller-diameter rolls to reduce the contact area – Taking smaller reductions-per-pass to reduce the contact area – Rolling at elevated …
How do you reduce a flattened roll?
Roll ﬂattening also can be reduced by (a) decreasing the reduction per pass and (b) reducing friction at the roll-sheet interface.
What extreme operating conditions are rolls exposed to during rolling operations?
Rolls are subject to extreme operating conditions during the metal rolling process. Conditions include, tremendous forces, bending moments, thermal stresses, and wear. Roll materials are selected for strength, rigidity, and wear resistance.