Why Heat Treatment of casting is done?To improve micro-structureTo Reduce Grain boundary segregationNoneBoth A & B

Analyzing the Question

The question pertains to the reasons behind heat treatment of castings. Let's break down the options to determine the correct answer.

1. Understanding Heat Treatment: Heat treatment is a process used to alter the physical and sometimes chemical properties of a material. In the context of castings, it is primarily used to improve mechanical properties.

2. Evaluating Options:

   • Option A: To improve micro-structure: This is accurate as heat treatment can refine the microstructure of the material, leading to enhanced mechanical properties such as strength and toughness.
   • Option B: To reduce grain boundary segregation: This is also true. Heat treatment helps to reduce segregation of alloying elements at the grain boundaries, which can improve the overall performance of the casting.
   • Option C: None: This option does not apply because both A and B are valid reasons for heat treatment.
   • Option D: Both A & B: This is the combined effect of improving microstructure and reducing grain boundary segregation.

Conclusion

Considering both options A and B are correct and valid reasons for heat treatment of castings, the comprehensive answer is:

Final Answer

Both A & B