ASRB NET — Farm Machinery & Power / Land & Water Management Engineering / Agricultural Structures & Process Engineering · India · Agricultural Scientists Recruitment Board (ICAR)
Original practice questions written to the published syllabus · not past papersHow farm machines are made: joining, casting, machining, heat treatment and measurement, up to building a prototype.
In the exams: ICAR AICE-JRF/SRF subject 39 (FMPE) Unit 7 Manufacturing Technology; ASRB NET Farm Machinery & Power; machinery fabrication in PRC ABE
ASRB NET — Farm Machinery & Power
Manufacturing as listed in the discipline: process selection, materials for soil-engaging parts, heat treatment, welding and its testing, machining calculations (cutting speed, time, indexing), and fabrication of machinery.
How our questions for ASRB NET spread across the units of Workshop Technology & Manufacturing. Difficulty: 37 easy, 57 medium, 31 hard.
| Lathe operations | 13 | |
| Drilling, milling and shaping | 13 | |
| MIG and TIG welding and testing of welded joints | 11 | |
| Casting processes | 11 | |
| Metrology and measurement in the workshop | 11 | |
| Fitting, carpentry and smithy | 10 | |
| Jigs, fixtures and gauges | 10 | |
| Prototype fabrication | 10 | |
| Arc and gas welding | 9 | |
| Press working of sheet metal | 9 | |
| Heat treatment of steels | 9 | |
| Specification of engineering materials | 9 |
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
Which oxy-acetylene flame is normally used for welding or braze welding brass?
D. Oxidising flame
Brass contains zinc, which boils off and causes porosity; a slightly oxidising flame forms an oxide film that limits zinc fuming. A neutral flame suits steel. Carburising and reducing flames (the same thing, with excess acetylene) would worsen zinc loss.
Further reading: Hajra Choudhury, Elements of Workshop Technology
Using the IIW formula, what is the carbon equivalent of a steel with 0.45% C, 0.75% Mn and negligible other alloying elements?
D. 0.575
CE = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15 = 0.45 + 0.75/6 = 0.45 + 0.125 = 0.575. 0.450 ignores manganese; 1.200 adds manganese at full weight; 0.700 divides manganese by 3. A value this high normally calls for preheat and low-hydrogen practice.
Further reading: IIW carbon-equivalent formula
Why is the sprue of a gating system tapered, with its narrow end at the bottom?
C. The falling stream speeds up, so a narrowing sprue keeps it full and stops air being drawn in
Velocity rises as √(2gh) down the sprue; by continuity the area must fall or the stream separates from the walls, creating low pressure that aspirates air and sand. Choking the flow rate is done by the gating ratio, not by slowing in the sprue; draft and shrinkage are not the reason.
Further reading: Hajra Choudhury, Elements of Workshop Technology
Which moulding-sand property allows steam and gases to escape from the mould when hot metal is poured?
D. Permeability
Permeability is the ability of the sand mass to pass gas; low permeability causes blowholes. Refractoriness resists high temperature, collapsibility lets the casting contract and the sand be knocked out, and green strength holds the moist mould together.
Further reading: Hajra Choudhury, Elements of Workshop Technology
For a tool–work pair, Taylor's equation is VT^0.25 = 300 (V in m/min, T in min). What tool life is expected at 150 m/min?
D. 16 min
T = (C/V)^(1/n) = (300/150)^4 = 2⁴ = 16 min. 2 min treats life as proportional to the speed ratio; 4 min squares instead of raising to the fourth power; 1.19 min takes the 0.25 power instead of the 4th.
Further reading: Groover, Fundamentals of Modern Manufacturing
A shaper has a stroke of 200 mm and makes 30 cutting strokes per minute. The return stroke takes half the time of the cutting stroke. What is the average cutting speed?
A. 9 m/min
V = LN(1 + m)/1000 with m = return time / cutting time = 0.5: V = 200 × 30 × 1.5/1000 = 9 m/min. 6 m/min ignores the quick return; 12 m/min uses a 1:1 ratio; 18 m/min uses (1 + 1/m).
Further reading: Hajra Choudhury, Elements of Workshop Technology
A part is located on two accurately bored holes using two pins. Why is one of the pins made as a diamond (relieved) pin?
C. It allows for centre-distance tolerance while still stopping rotation
Two full round pins would jam if the hole spacing varies within tolerance. The diamond pin is relieved along the line joining the holes, so it only stops rotation about the round pin. It is not about hardness, and foolproofing is a separate design requirement.
Further reading: Hajra Choudhury, Elements of Workshop Technology
A forged high-carbon steel ploughshare has been hardened by quenching. What should follow before it is used in stony soil?
C. Tempering at a low to moderate temperature to restore toughness
As-quenched martensite is very hard but brittle and can shatter on stones; tempering trades a little hardness for toughness. Normalising and annealing would soften the share and lose the hardening, and as-quenched steel is at its least tough.
Further reading: Hajra Choudhury, Elements of Workshop Technology
A 2 m length of 50 mm × 10 mm mild steel flat bar is needed for a prototype. Taking the density of steel as 7850 kg/m³, what is its mass?
D. 7.85 kg
Volume = 0.05 × 0.01 × 2 = 0.001 m³; mass = 7.85 kg. 78.5 and 0.785 kg are decimal slips; 3.93 kg uses 1 m.
Further reading: Hajra Choudhury, Elements of Workshop Technology
Which of these belongs in the bill of materials for a prototype seed drill?
A. Each part's material specification, stock size, quantity and make-or-buy status
A bill of materials lists every part with its material, stock size, quantity and whether it is made or bought; it drives purchasing, cutting lists and costing. Test results, operating costs and staffing belong in other documents.
Further reading: Hajra Choudhury, Elements of Workshop Technology
Ten here, 125 in the app. The Laisha app has every practice question we have written to ASRB NET in this subject, marked as you go, with timed papers, a jump-to-unanswered list and a certificate when you pass at 70 per cent.
Free for ten days, then one subscription of US$10 a month. We would rather say so here than have you find it later.
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