## Materials Science and Manufacturing Engineering Miscellaneous

#### Materials Science and Manufacturing Engineering

1. The surface irregularities of electrodes used in an electrochemical machining (ECM) process are 3 μm and 6 μm as shown in the figure. If the work-piece is of pure iron and 12V DC is applied between the electrodes, the largest feed rate is mm/min. Conductivity of the 0.02 ohm–1 mm–1 electrolyte Over-potential voltage 1.5 V Density of iron 7860 kg/m3 Atomic weight of iron 55.85 gm Assume the iron to be dissolved as Fe+2 and the Faraday constant to be 96500 Coulomb.
1. 51.542 mm/min
2. 52.542 mm/min
3. 50.542 mm/min
4. 49.542 mm/min

1.  R = ρL = (1 / 0.02)× 0.009 = 50 ×0.009 Area Area Area

 I = V = (12 - 1.5) × Area = 23.333 × Area R 50 × 0.009

L = 3 + 6 = 9 μm = 0.009
 MRR = AI = 55.85 × 23.333 × Area ρZF 7860 × 10-6×96500

= 0.98189 × Area
 MRR = 0.8590 mm/sec = 0.8590 × 60 mm/min Area

= 51.542 mm/min

##### Correct Option: B

 R = ρL = (1 / 0.02)× 0.009 = 50 ×0.009 Area Area Area

 I = V = (12 - 1.5) × Area = 23.333 × Area R 50 × 0.009

L = 3 + 6 = 9 μm = 0.009
 MRR = AI = 55.85 × 23.333 × Area ρZF 7860 × 10-6×96500

= 0.98189 × Area
 MRR = 0.8590 mm/sec = 0.8590 × 60 mm/min Area

= 51.542 mm/min

1. Requirement in the design of jigs and fixtures
P. Heavy clamping force on the workpiece
Q. Clamping on rough surfaces of workpiece
R. Four workpieces in a line to be machined in one loading
S. Drilling and reaming of workpiece in one loading
Recommended device
1. Clamp wlth a floating pad
2. Slip renewable bush
3. Indexing bush
4. Equalizing clamp
5. Strap clamp
1. P Q R S
5 1 4 2
2. P Q R S
1 4 5 3
3. P Q R S
5 1 2 3
4. P Q R S
4 5 3 2

1. NA

##### Correct Option: B

NA

1. Match the following
A. Rail sections
B. Plastic sheets
C. Allen bolts
D. Porous bearing
1. Powder metallurgy
2. Rolling
3. Cold forming
4. Transfer moulding
5. Calendering
6. Injection molding
1. A–2, B–5, C–3, D–1
2. A–5, B–2, C–3, D–1
3. A–1, B–5, C–3, D–2
4. A–2, B–3, C–5, D–1

1. A–2, B–5, C–3, D–1

##### Correct Option: A

A–2, B–5, C–3, D–1

1. Powder metallurgical components have
1. same density as that of cast products
2. higher density than cast products
3. lower density than cast products
4. higher density than forged products

1. NA

##### Correct Option: C

NA

1. Match the following
Process
A. Explosive welding
B. Brazing
C. Thermit welding
D. Manual metal arc welding
Associated Mechanism
1. Liquid state
2. Solid state
3. Solid liquid state
4. Liquid state Chemical
1. A-2, B - 3, C-4, D-4
2. A-3, B - 2, C-4, D-4
3. A-4, B - 3, C-2, D-1
4. A-2, B - 3, C-4, D-1

1. A-2, B - 3, C-4, D-4

##### Correct Option: A

A-2, B - 3, C-4, D-4