This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
Grain elongation is due to 
Select and explain. 
A. Cold working, B. Recrystallisation, C. Recovery, D. Age hardening
A: Cold working
Answer: A: Cold working 
Explanation: The average grain size of the recrystallized structure depends on the initial number of nuclei. The more severe the degree of cold working, the greater is the number of such nuclei. The grain size for the recrystallized metal can range from rather relatively fine to fairly coarse.
Phillips 12th edition page no 405