A. Is in the form of free Si
B. Indicates that steel is not deoxidised properly
C. Decreases the blow holes formation tendency in castings
D. None of these
Related Mcqs:
- Straight silicon steel (containing Si from 0.5 to 5%) because of their low hysteresis loss and high magnetic permeability are used for electrical appliances. Which of the following electrical appliances made of silicon steel contains maximum percentage of silicon (about 4%) ?
A. Armature of small motors/generators
B. Generators and small motors
C. Induction motors
D. High frequency transformers - Presence of high amount of silicon in cast iron________________?
A. Suppresses the decomposition of Fe3C
B. Increases the formation of graphite
C. Increases the contraction of the metal
D. Reduces its fluidity - Containers made of high silicon cast iron (14% Si) are not suitable for the storage of ____________________?
A. Acetic acid
B. Benzoic & boric acids
C. Phosphoric acid (95%) & sulphuric acid (95%)
D. Hydrochloric acid (concentrated) - Silicon percentage in iron castings to have maximum hardness should be about__________________?
A. 0.3
B. 0.5
C. 0.8
D. 2.5 - Silicon percentage in acid resistant cast iron is about________________?
A. 4
B. 8
C. 14
D. 20 - Presence of nitrogen in steel___________________?
A. Makes it brittle
B. Increases its strength
C. Increases its hardness
D. Is desirable - Presence of even very minute amount (say 0.1%) of ______________ in copper, reduces its electrical conductivity very seriously?
A. Bismuth
B. Arsenic
C. Antimony
D. Both B. and C. - The presence of impurities in iron_________________?
A. Increases its melting point
B. Does not affect its melting point
C. Decreases its melting point
D. Makes it malleable - Presence of 0.3 to 0.5% arsenic in copper increases its____________________?
A. Ductility
B. Malleability
C. Tenacity & hardness
D. Electrical conductivity - Presence of high phosphorous in cast iron increases its____________________?
A. Fluidity
B. Melting point
C. Shrinkage
D. Tensile strength
