General coarseness of the microstructure (Melt) is largely determined by the _______

[Quang Hiếu]

General coarseness of the microstructure (Melt) is largely determined by the _______
A. Grain size of base metal
B. Composition of base metal
C. Texture
D. Nothing can be said

 

[Nguyễn Thị Thuý]

Answer: a
Explanation: the general coarseness of the microstructure is largely determined at the melt by the grain size of the base metal. Unfortunately, the base metal at the transition zone receives the most severe thermal cycle and after high-energy welding in particular the grains in this zone tend to grow and become relatively coarse.