Question

A steel plate 30 mm thick is to be rolled to 14 mm in a four-high mill having roll diameter 680 mm. If yield stress is 200 MPa, and the thickness of the sheet at neutral plane is 17.2 mm, the Forward slip and Backward slip are, respectively

• A. 23% & 43%
• B. 43% & 23%
• C. 23% & 9%
• D. none

Answer 1

The correct option is A 23% & 43%

Rolling
A steel plate

$H_0=30mm$

$H_1=14mm$

$\Delta H=H_o-H_1=50-14=36mm$

$D_R=680mm,$

$R=340mm$

${\sigma }_y=200MPa$

$H_{neutral}=17.2mm$
Forward slip; Backward slip = ?

$V_1{H}_1=VH$

$\frac{V_1}{V}=\frac{H}{H_1}=\frac{17.2}{14}=1.22$

$V_o{H}_o=VH$

$\frac{V_o}{V}=\frac{17.2}{30}=0.573$

Forward slip $=\frac{V_1-V}{V}=\frac{V_1}{V}-1$

$=1.2285-1=22.85$

Backward slip $=\frac{V-V_o}{V}$

$=1-\frac{V_o}{V}=1-0.5733=42.6$%