JFE TECHNICAL REPORT
No.15 Special Issue on "Steel Bar and Wire Rod"
A technique for obtaining ultra fine prior austenite grain in the high frequency induction quenched portion for automotive parts was developed for increasing strength. The prior austenite grain size greatly depended on the maximum heating temperature of the induction quenching and the addition of Mo. Choosing maximum heating temperature of above Ac3 and adding up to 0.4 mass% of Mo make the prior austenite grain remarkably fine.
The prior austenite grain size obtained was about 3 μm. The tensile properties of the induction quenched portion showed the tensile strength of more than 2000 MPa and the elongation of more than 10%. The strength ductility balance of the high frequency induction quenched portion is superior than that of conventional quenched and tempered steel.
Read full technical paper at http://www.jfe-steel.co.jp/en/research/report/015/pdf/015-07.pdf
(Source - JFE)