A solid cylindrical workpiece made of 304 stainless steel is 150 mm in diameter and 100 mm is high. It is reduced in height by 50%, at room temperature, by open-die forging with flat dies. Assume that the coefficient of friction is 0.2. Calculate the forging force at the end of the stroke.

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Answer:

45.3 MN

Explanation:

The forging force at the end of the stroke is given by

F = Y.π.r².[1 + (2μr/3h)]

The final height, h is given as h = 100/2

h = 50 mm

Next, we find the final radius by applying the volume constancy law

volumes before deformation = volumes after deformation

π * 75² * 2 * 100 = π * r² * 2 * 50

75² * 2 = r²

r² = 11250

r = √11250

r = 106 mm

E = In(100/50)

E = 0.69

From the graph flow, we find that Y = 1000 MPa, and thus, we apply the formula

F = Y.π.r².[1 + (2μr/3h)]

F = 1000 * 3.142 * 0.106² * [1 + (2 * 0.2 * 0.106/ 3 * 0.05)]

F = 35.3 * [1 + 0.2826]

F = 35.3 * 1.2826

F = 45.3 MN

The answer is "45.3 NM".

There at end of the movement, the forging force is given by

[tex]\to F = Y \times \pi \times r^2 \times [1 + (\frac{2 \mu r}{3h})][/tex]

h is the final height.

[tex]\to h = \frac{100}{2}= 50 \ mm[/tex]

The ultimate radius is determined by following a volume constancy law, which states that volumes before deformation measured amount following distortion.

[tex]\to \pi \times 75^2 \times 2 \times 100 = \pi \times r^2 \times 2 \times 50\\\\\to 75^2 \times 2 = r^2\\\\\to r^2 = 11250\\\\\to r = \sqrt{11250}\\\\\to r = 106 \ mm\\\\\to E = \In(\frac{100}{50})\\\\\to E = 0.69\\\\[/tex]

You may deduce from the graph flow that [tex]Y = 1000\ MPa[/tex], thus we use the formula.

        [tex]= 1000 \times 3.14 \times 0.106^2 \times [1 + (\frac{ 2 \times 0.2 \times 0.106}{3 \times 0.05})]\\\\= 1000 \times 3.14 \times 0.011236 \times [1 + (\frac{ 0.0424}{0.15})]\\\\= 35.3 \times 1.2826\\\\ = 45.3 \ MN\\\\\\[/tex]

Therefore, the answer is "45.3 NM".

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