Roll pass design pdf

Area reduction. Bite angle. Bar length Rolling speed Rolling time Idle time Loop or tension value between stands. The reduction must be applied after a degree rotation of the bar at each stand. The ovals are twisted to bring the long axis between the rolls. To be precise, there is one.

It needs rotating the square by 45, which can be obtained if we don't want to use twister guides with a slight axial displacement of one roll in the stand that produces the square. If you don't want the bar to be twisted you use the HV mill configuration with definite passes in vertical stands. From the roll pass design point of view, a CBM can be schematized as a succession of passes centered on the z-axis when x,y is the plane containing the roll axes. The purpose of the rolling process is to start from a relatively short bar with a large section area, aiming to obtain a very long product with a small section area.

Cross sectional area times bar length is a constant this is not strictly true for CBMs: some weight will be lost with scale and crop ends; but we can afford to neglect that loss. There is another, important law to remember: the flow is also a constant. If the finished stand delivers at a speed of 12 mps, then stand 1 must 'run' at 0. In this case the constant is about , i. And, you have no problems in setting the speed at each stand, as each stand has its own independent motor.

If we focus on a horizontal stand of a continuous mill for rounds, we see: - that the rolls apply a 'reduction' vertically ; - that this reduction produces a wanted 'elongation'; - that reduction produces a 'spread' sideways.

This is called Spread. Lambda defined as ratio between exit and entry length, but. To draw the oval groove we need to know its radius R. Shape rolling of initial billet with initial cross section x mm2 to 30x30 mm2 consisting of sequential passes of square-oval-.

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Roll pass design About this Item Trinks, W. Please choose another view to download individual pages. Ebook PDF. Image JPEG. Image TIFF. Current page scan 7. Left page scan 7. Right page scan 7. Strip has thickness less than or equal to 4. Sheet has thickness less than or equal to 4. Differentiate among ingot, bloom, billet and pencil ingot.

Ingot is a mass of metal cast in a convenient form for shaping, remelting or refining. There are no specific standard dimensions for ingot. Blooms and billets are smaller in size. Billets have a cross section of mm X mm and that of blooms are greater than mm X mm.

Pencil ingots are small ingots in kilograms produced in mini steel plants. Determine the location of neutral point for flat rolling. Neutral point is the point along the contact length where velocity of the strip equals velocity of the roll.

The neutral point is located at. Calculate roll load for flat rolling. Calculate power required for this schedule.

Calculate torque for this schedule. So Change in Roughing Pass: For 5 roughing passes and Conclusion: Roll pass design not only aims to improve the size, shape and mechanical properties of the rolled products but also it seeks to optimize the roll pass process itself.

Although roll pass design for section rolling is usually based on the empirical knowledge of human experts, most of the empirical formulae only give good results within a limited range of applications. Section rolling has always represented the most complicated rolling process for optimization. A good roll pass design must ensure a profile with a smooth surface and correct dimensions within the limits specified in the concerned standard.