METHOD FOR ENHANCING FATIGUE STRENGTH OF STEEL CRANKSHAFTS Russian patent published in 2006 - IPC C21D9/30 C21D7/04 

FIELD: metallurgy, namely strengthening crankshafts of internal combustion engines at making and restoring them.

SUBSTANCE: method comprises steps of simultaneously rolling out both fillets of one journal of crankshaft by means of three pairs of deforming rollers with different profile radiuses; mounting rollers by angle φ = 43 - 48° relative to axis of worked journal of shaft and applying working load to rollers by the same angle. Profile radius of minimum curvature rollers R¹ _r = 0.96 R_f where R_f - radius of worked fillet. Deforming effort acting upon each roller is determined according to condition for providing percentage depth of plastic deformation propagation at rolling out by means of minimum curvature rollers h_s/D = 0.015. Curvature degrees of other two pairs of rollers are determined according to condition providing specific contact pressure 2000 - 2100 MPa and 2400 - 2500 MPa by means of given formula where p - mean specific pressure in contact zone, MPa; F - deforming effort, N; R_r - radius of rolled out fillets, m; D_j - diameter of crankshaft journal, m.

EFFECT: enhanced efficiency and quality of worked surface of fillets of crankshafts.

5 dwg, 2 tbl, 1 ex