Application of Grain Boundary Engineering in Lead-free “Green Steel”

Abstract

The development of a non-leaded free-machining steel has used atom probe tomography to measure the concentration of tin atoms at the ferrite grain boundaries. Comparing to lead-containing 12L14 and 1215 steels, 12T14 has proven to be equal or superior in terms of machinability. Atom probe analysis has revealed that grain boundary segregation of tin is responsible for the improved machinability performance.