As we stated in the article about metal rolling processes, the flat rolling process is one out of two types of metal rolling processes. With the flat rolling processes, work parts such as slabs are converted into metal strips, sheets, and plates.
Here you can find out detailed information about the designing process parameters of flat metal rolling processes. You can use the calculators below to design your flat metal rolling process for the specific production line.
To start to design a flat rolling process, you need to start from the calculation of the draft. This parameter gives the total squeeze rate of the work between two rolls. You can find this value by calculating the thickness difference between thicknesses before the rolls and after the rolls.
If there are series of rolls in the production line, the total reduction of the thickness can be found with the summation of drafts which are divided by the original thickness of starting part. This calculation must be made for each roll sets in series of rolls. The formula of reduction for individual set of rolls;
The velocity of the input workpiece and output metal is also a very important parameter to calculate. According to basic physics, the total volume of the input metal and output metal is the same in rolling operations. By using this principle, the input and output speeds of the metal in a flat metal rolling operation can be calculated. Consider this equation;
In this equation, the values are denoted with ‘t’ is the input and output thicknesses of workpieces. The values which are denoted with ‘v’ are the input and output values of velocities. ‘w’ is the width of the input and output metal in the rolling process.
With the defined process parameters, you can find the velocity ratio of the input and output workpieces.
From classical mechanics, the rotational or circumferential speed of the rolls can be calculated easily. You just need to multiply the angular velocity with the radius of the roll.
The velocity of the input metal to roll is smaller than the rotational velocity of the roll. In the meantime, the velocity of the output metal in the rolling application is bigger than the rotational velocity of the roll. Because of these speed differences, a physical phenomenon takes place in flat metal rolling processes called slip. This slip takes place in the forward direction and it is calculated with this formula again;
In this equation, ‘Vf’ is the velocity of the exiting work and the ‘Vr’ is the rotational velocity of the rolls.
The flow stress of the metal in the designed rolling process can be calculated by using the calculator below. Flow stress is very important because other process parameters are calculated with this value.
The use of the calculator above is very simple. Just enter the required values inside the brackets then click on the ‘Calculate!’ button to see the result. If you want to make another calculation, click on the ‘Reset’ button.
In this calculation, the entrance thickness and exiting thickness of the work part is very simple. You can find information about the other parameters from this article about flow stress.
You can use the recommended units inside the parentheses. If you do not have a consistent value of units, you can use the MB-Unit Converter to convert your units into consistent sets of values.
Sticking can be a very important problem in flat metal rolling processes. The design must be made with the consideration of sticking. Sticking is about the friction between the work part and the rollers. If the friction force exceeds the flow stress of the metal at that temperature, the metal will stick on the roller which will demolish the production process.
To avoid sticking, you need to calculate the maximum draft for your flat metal rolling process. Use the calculator below to calculate it;
The calculation of the required rolling force, torque, and power are very simple. Use the calculator below.
In this calculator; You just need to enter the radius of the rollers additionally.
So, the general design considerations in flat metal rolling processes are very simple like this.
Mechanical Base does not accept any responsibility for calculations made by users in calculators. A good engineer must check calculations again and again.
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Source Of The Thumbnail: www.doitpoms.ac.uk/tlplib/metal-forming-2/rolling.php