Question

1) Turbulence during pouring of the molten metal is undesirable since (two best answers):

a) it causes discoloration of the mold surfaces, b) it dissolves the binder used to hold together the sand mold, c) it increases erosion of the mold surfaces, d) it increases the formation of metallic oxides that can become entrapped during solidification, e) it increases the mold filling time, and f) it increases total solidification time

2) Total solidification time is defined as a) time between pouring and complete solidification, b) time between pouring and cooling to room temperature, c) time between solidification and cooling to room temperature or d) time to give up the heat of fusion

3) In a sand-casting mold, the V/A ratio of the riser should be_____ the V/A ratio of the casting itself. a) equal to, b) greater than, c) smaller than d) none of the above

4) In foundry work, a runner is a) channel in the mold leading from the sprue to the main mold cavity, b) foundryman who moves the molten metal to the mold, c) vertical channel into which molten metal is poured into the mold, d) none of the above.

5) In sand casting, the volumetric size of the pattern is _________ that of the product. a) bigger than b) same size as c) smaller than d) Any of the above, depending on the cast material

6) Investment casting is also known as a) fast-payback molding, b) full-mold process, c) lost-foam process, d) lost-pattern process e) lost-wax process

7) A riser in casting is described by (three correct answers): a) an insert in the casting that inhibits buoyancy of the core b) gating system in which the sprue feeds directly into the cavity, c) metal that is not part of the casting, d) source of molten metal to feed the casting and compensate for shrinkage during solidification, e) waste metal that is usually recycled

8) A sphere is sand cast in an experiment. If its diameter increases 41% then the solidification time of the larger sphere will increase: a) 2 times. b) 4 times. c) 8 times. d) 9 times.

9) The correct order for liquid metal to flow in a sand mold is a) Sprue, cope, drag, cavity. b) Cavity, runner, cope, drag. c) Cope, sprue, gate, cavity. d) None of the above.

10) Which of the following casting processes are expendable mold operations (four correct answers): a) centrifugal casting, b) die casting, c) investment casting, d) low-pressure casting, e) sand casting, f) shell molding, g) slush casting, h) vacuum molding

Answer 1

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② A reisers in casting ů described by (b) gating system in which the spreme feeds directly into the cality (a) Melal that is not part of Casting (d) Sourece of molten metal to feed the Casting and and compensate fore shreinlage durcing solidlification 2 & smaller spheree y tard Esmallen = 0² sphere 36 when D Ů increesed by ult. D = 10 ul Dsmallen langen flangen sphere (ej? = 10980

11980² teargen sphere Esmallen sphere 36 a Alargen =ax & smallen sphere sphere The solidlification time will increase by a fimes And ů (a) The correct corder for liquid metal to flow in a sand mould ei spreue, Runner, cality But here no option Matches So ansenere i col None of the above Expandable mold operation aree by die casting ki Investment casting (en sand casting ch) shell molding