Please help me.. i'm zero in automobile engineering =(

Comparison of used and new crankshaft after tempering process

Hey guys,i am the material engineering student and new in this forum, i have problem in getting the information about comparison of used and new crankshaft after tempering process, so i would like to asking you about the problems or defects recently happened on crankshaft, and the time to crankshaft usually get problem. What type of material they are used to produced crankshaft. More explanation in detail required. Thanks guys for help me.. 😉😉😉