Forging of Parts Having Strength Distribution Using Tailor Friction-Welded Billets Composed of Steel Bars Having Different Quenchabilities
Parts having a strength distribution were produced from tailor friction-welded billets consisting of steel bars having different quenchabilities. Chrome steel SCr420 and mild steel S25C bars having high and low quenchabilities, respectively, were joined by friction welding. The tailor friction-welded billets were forged, and then quenched so as to have a strength distribution. The cold formability of the tailored billet was first examined from simple compression in the normal and tangential directions to the joint. No cracks appeared even for an 80% reduction in height in the compression. In a tensile test of the 80% reduced billet, the softer S25C side was fractured and the interface was not fractured. The tailor billets have enough cold formability. The thermal influence around the joint of the tailor friction-welded billets was eliminated by annealing, and thus inhomogeneous deformation around the joint in forging was prevented. A shaft having a high strength flange and a connecting rod having high strength and machinability were produced by forging and quenching of the tailored billet.
Fabrizio Micari and Livan Fratini
T. Maeno et al., "Forging of Parts Having Strength Distribution Using Tailor Friction-Welded Billets Composed of Steel Bars Having Different Quenchabilities", Key Engineering Materials, Vols. 622-623, pp. 186-193, 2014