... rather difficult to machine.Background reading M. F. Ashby and D. R. H. Jones, Engineering Materials I, 2nd edition, Butterworth-Heinemann,1996, Chapters 21 , 22 , 23 and 24 .Further readingK. ... metal.Background reading M. F. Ashby and D. R. H. Jones, Engineering Materials I, 2nd edition, Butterworth-Heinemann,1996, Chapters 7 (Case study 2) , 10, 12 (Case study 2) , 27 .Further readingI. ... wear and tear. Untempered martensite is far too brittle for hammerheads.Having solved the immediate problem to our satisfaction we still wondered how themanufacturer had managed to harden the...