PLEASE HELP WILL THUMBS UP

b) The two bushings that are pressed into the chain side bar are made of 1018 steel. They are too soft and will wear out quickly. What is the disadvantage of making them out of heat treatable (hard) steel? [note: 1018 steel cannot be hardened by heat treating]: c) Why can 1018 steel not be hardened by heat treating (what does it need?) : d) What process can we use to allow the surface to be very hard while maintaining ductility of the part? e) Describe in detail how the end of chapter problem number 19 of chapter 5 can be used