7. Identify the three sources of contraction in a metal castingafter pouring. 8. What is directional solidification and what ischill in casting? 9. Total solidification time is defined as(select one): (a) time between pouring and complete solidification,(b) time between pouring and cooling to room temperature, (c) timebetween solidification and cooling to room temperature, (d) time togive up the heat of fusion? 10. What is the difference between apattern and a core in making sand casting mould? 11. What isfunction of riser? 12. What properties determine the quality of asand mould for sand casting?
