Machinability of hard alloys and tool steels is improved by

ANS:B - annealing

Annealing is a heat treatment process used to soften metals, relieve internal stresses, and improve their ductility and toughness. It involves heating the metal to a specific temperature (usually above its recrystallization temperature) and then allowing it to cool slowly in a controlled manner. This process helps to refine the microstructure of the metal, reduce hardness, and promote the formation of a more uniform grain structure. While annealing is beneficial for improving the formability, ductility, and toughness of metals, it may not directly improve the machinability of hard alloys and tool steels. Machinability refers to the ease with which a material can be cut, drilled, or shaped using machining tools such as lathes, milling machines, or drills. Hard alloys and tool steels are often specifically engineered to have high hardness and wear resistance, which can make them challenging to machine. Improving the machinability of hard alloys and tool steels typically involves processes such as spheroidizing, which softens the material and reduces its hardness, making it easier to machine. Therefore, while annealing may have indirect effects on machinability by altering the material's properties, it is not typically used specifically for improving the machinability of hard alloys and tool steels. Instead, processes such as spheroidizing or other specialized machining techniques are employed for this purpose.