400 mm व्यास के वेल्लक(रोल) वाले दो-उच्च मिल का उपयोग करके एक पट्टी को 36 mm से 20 mm की मोटाई तक वेल्लित किया जाना है। बिना सहायता बाइट के लिए घर्षण के गुणांक का अनुमानित मान______ होगा:

Question

Question

This question was previously asked in

HPCL Engineer Mechanical 04 Nov 2022 Official Paper (Shift 2)

Answer 1

Concept:

The relationship between reduction or draft, coefficient of friction and radius of rolls is as follows:

\(Δ h = μ^2 R \)

where, Δ h = Reduction or draft = (h_initial) - (h_final)

R = Radius of rolls, μ = Coefficient of friction

Calculation:

Given:

Given, h_i = 36 mm, h_f = 20 mm, D = 400 mm ⇒ R = D/2 = 200 mm

Δ h = (36-20) =16 mm
\(Δ h = μ^2 R \Rightarrow 16 = μ ^2 \times 200 \)

\(\mu = \sqrt{0.08} = 0.2828\)