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| Q. |
Type metal used in printing press is an alloy of – |
| A. | lead and copper |
| B. | lead and antimony |
| C. | lead and bismuth |
| D. | lead and zinc |
| Answer» B. lead and antimony | |
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Explanation: In printing, type metal (sometimes called hot metal) refers to the metal alloys used in traditional type founding and hot metal typesetting. Lead is the main constituent of these alloys. Antimony and tin are added to make the character produced durable and tough while reducing the difference between the coefficients of expansion of the matrix and the alloy. Cheap, plentifully available as galena and easily workable, lead has many of the ideal characteristics, but on its own it lacks the necessary hardness and does not make castings with sharp details because molten lead shrinks and sags when it cools to a solid. |
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