Question

During a tool-wear test with a HSS tool, the following data are obtained:

Tool life	Cutting speed
30 min	20 m/min
5 min	75 m/min

The tool life of the tool if cutting velocity is 50 m/min, is

• A. 8.6 min
• B. 7.3 min
• C. 12.7 min
• D. 18.5 min

Answer 1

The correct option is A 8.6 min

$V_3=50\text{m/min},T_3=?$

$V_1{T}_1^n=V_3{T}_3^n$
$20(30{)}^{0.74}=50(T_3{)}^{0.74}$

$\Rightarrow T_3=8.6\text{min}$