High Rigidity to Weight Ratio:
Machine tool frames are subjected to high cutting forces and vibrations during operation. Therefore, it is essential for the frame to have high rigidity to weight ratio to minimize deflection and ensure precision in machining processes. A high rigidity to weight ratio helps in maintaining the stability of the machine tool, resulting in improved performance and accuracy.

Graphite in the Form of Nodules:
Graphite in the form of nodules is not a desirable characteristic for a machine tool frame. Graphite nodules can weaken the material and reduce its strength, leading to potential failure during operation. It is important to choose materials that are free from graphite nodules to ensure the structural integrity and durability of the machine tool frame.

Low Hardness:
Having low hardness is not ideal for a machine tool frame as it can lead to wear and deformation under the high stress and load conditions experienced during machining operations. A material with low hardness may not be able to withstand the forces exerted on it, resulting in premature failure and reduced tool life. Therefore, it is important for the machine tool frame to have a suitable hardness to ensure its longevity and performance.

High Work Hardness:
High work hardness is beneficial for a machine tool frame as it enhances the material's ability to resist wear, abrasion, and deformation during machining processes. A material with high work hardness can maintain its shape and integrity under high cutting forces, leading to improved performance and durability of the machine tool frame. It is important to select materials with high work hardness to ensure the longevity and reliability of the machine tool.