Tool Materials ( Powder Metallurgy )
1. ______ enables us to shape a larger metallic object by removing a part or thin layer of the metal from its surface to the required shape.
A. Electrical contact materials
B. Bearing materials
C. Tool materials
D. Sintered Friction materials
Answer:: C
2. Cemented carbides are commonly known as ‘Hard Metals’.
A. True
B. False
Answer:: A
3. The modern production of hard metal is attributed to ________
A. Kieffer
B. Schroter
C. Schwarzkopf
D. Osram Studiegesellschaft
Answer:: B
4. ______ carbide alloys possess better resistance to diffusion wear under seizure conditions.
A. Medium-grained
B. Ultra-fine grained
C. Coarse-grained
D. Fine-grained
Answer:: C
5. Which of the following is not a characteristic of vibratory mill used for milling of cemented carbide?
A. Shorter milling time (1-2 days)
B. Wear of balls and mills is reduced
C. Ratio of powders to balls in mills = 1:3.5 – 1:5.5
D. Ratio of powders to balls in mills = 1:1 – 1:3
Answer:: D
6. In which organic liquid is the lubricant, paraffin wax dissolved?
A. Gasoline
B. Ether
C. Light hydrocarbons
D. Alcohol
Answer:: A
7. The classical method of production of cemented carbide tips is ________
A. Hot pressing
B. Infiltration
C. Double-sintering
D. Liquid phase sintering
Answer:: C
8. During _______, no liquid phase forms and ________ of only the binder metal occurs.
A. Pre-sintering, liquid phase sintering
B. Liquid phase sintering, pre-sintering
C. Pre-sintering, solid phase sintering
D. Solid phase sintering, pre-sintering
Answer:: C
9. Milled powder mixtures are unsuitable for automatic pressing in comparison to agglomerated carbide-cobalt powder mixtures.
A. True
B. False
Answer:: A
10. _________ is used to produce large carbide balls, bushes and hollow sections with more uniform density.
A. Isostatic pressing
B. Extrusion compaction
C. Rolling
D. Forging
Answer:: A
11. Which of the following is not a characteristic of hot-pressed material?
A. Hard
B. Ductile
C. Wear- resistant
D. Zero residual porosity
Answer:: B
12. Which of the following is the correct sequence of grinding cemented carbides?
A. Rough grinding
B. Coarse grinding, polishing, and fine grinding
C. Rough grinding, and final grinding
D. Fine grinding
Answer:: C
13. ______ of cemented carbide is the measure of the completeness of sintering operation.
A. Density
B. Volume
C. Strength
D. Ductility
Answer:: A
14. Cemented carbide grades can be classified into _____ groups, according to their density by using Hg as a buoyancy medium.
A. 2
B. 3
C. 4
D. 5
Answer:: A
15. _________ of cemented carbide tools is used as a measure of wear performance.
A. Hot hardness
B. Transverse rupture strength
C. Compressive strength
D. Hardness
Answer:: D
16. Transverse-Rupture strength of cemented carbide is a measure of _________
A. Hardness
B. Wear resistance
C. Toughness
D. Compressive strength
Answer:: C
17. The oxidation resistance of WC-Co composition is higher than that of the WC-TiC-Co composition.
A. True
B. False
Answer:: B
18. Lower thermal conductivity of cemented carbides leads to formation of _________
A. Brazing cracks
B. Comb-type cracks
C. Grinding cracks
D. Crumbling
Answer:: C
19. Which of the following property of cemented carbide increases on increase in Co content?
A. Coefficient of thermal expansion
B. Hardness
C. Density
D. Thermal conductivity
Answer:: A
20. The cutting performance of cemented carbide can be plotted as _________
A. T-V curve
B. C-P curve
C. I-V curve
D. M-V curve
Answer:: A
21. The microstructure of WC-Co alloy contains ____ phases.
A. 1
B. 2
C. 3
D. 4
Answer:: B
22. The microstructure of WC-TiC-Co alloy contains ____ phases.
A. 1
B. 2
C. 3
D. 4
Answer:: C
23. ______ is the most important application of cemented carbides.
A. Dies
B. Cutting Tools
C. Drilling Tools
D. Deep drawing Tools
Answer:: B
2. Which of the following is not a characteristic of cemented carbide cutting tools?
A. Extremely hard
B. Very brittle
C. High red hardness
D. Low red hardness
Answer:: D
24. Cemented carbide cutting tool is advantageous in mass production.
A. True
B. False
Answer:: A
25. ________ occurs due to material built-up at the cutting edge.
A. Brazing cracks
B. Comb-type cracks
C. Crumbling
D. Grinding cracks
Answer:: C
26. Which of the following is not a cause for failure of the cutting tools?
A. Crumbling
B. Hair-type cracks
C. Grinding cracks
D. Thermal shocks
Answer:: B
27. The phenomenon of ______ occurs by the combination of considerable pressure, high temperature and longer time of contact only within a certain speed range.
A. Brazing cracks
B. Grinding cracks
C. Crumbling
D. Built-up edge
Answer:: D
28. The wear due to the indenting action of hot, rough, hard and coiled chips behind the cutting-edge leads to ________
A. Cratering
B. Grinding cracks
C. Crumbling
D. Built-up edge
Answer:: A
29. _______ composition of the carbide cutting tool is suitable for roughing operations.
A. Low-Co
B. High-Co
C. Medium-Co
D. Ultra-high-Co
Answer:: B
30. High TiC content (25-60%) is used particularly for _________
A. High finish turning and drilling of steel
B. Roughing operation
C. Medium cuts and speeds on steel
D. Rough cuts on Cast iron
Answer:: A
31. Composite tips, consisting of a thin layer of TiC-Co bonded on a WC-Co grade use is rapidly increasing.
A. True
B. False
Answer:: A
32. Cemented carbide dies replace diamond dies for hole diameters between _______
A. 0.004-0.04 inch
B. 0.04-0.4 inch
C. 0.4-0.9 inch
D. 0.004-0.1 inch
Answer:: B
33. High-pressure nozzle made of cemented carbides are used in ________ industry.
A. Chemical
B. Sheet processing
C. Textile
D. Mining
Answer:: A
34. __________ are widely used as projectile cores for armor piercing weapons.
A. Sintered friction material
B. Cermet
C. Cemented carbide
D. Dispersion strengthened material
Answer:: C
