Question

In a reversing 2-high mill, a series of cold rolling process is used to reduce the thickness of a plate from 45mm down to 20mm. Roll diameter is 600mm and coefficient of friction between rolls and strip 0.15. The specification is that the draft is to be equal on each pass. Determine a) Minimum number of passes required? b) Draft for each pass?

Answer 1

Answer:

Explanation:

Given

Initial Thickness=45 mm

Final thickness=20 mm

Roll diameter=600 mm

Radius(R)=300 mm

coefficient of friction between rolls and strip ($\nu$)=0.15

maximum draft$(d_{max})=\nu ^2R$

$=0.15^2\times 300=6.75 mm$

Minimum no of passes$=\frac{45-20}{6.75}=3.70\approx 4$

(b)draft per each pass

$d=\frac{Initial\ Thickness-Final\ Thickness}{min.\ no.\ of\ passes}$

$d=\frac{45-20}{4}=6.25 mm$