Machinability and Machinability Index

Q. Machinability of steels is improved by the addition of

1. Sulphur
2. Silicon
3. Phosphorous
4. All of the above

Q. Pure metal poses a machinability problem in turning operations. The reason is the

1. Increased length of contact due to the production of continuous chip
2. Susceptibility to chemical reactions
3. Tendency to from intense adhesion joint with tool face
4. Absence of inclusions which aids chip formation