METHOD OF RECONDITIONING LARGE-SIZE NITRIDE-HARDENED CRANKSHAFT SCORED HOLLOW JOURNALS BY HIGH-FREQUENCY CURRENT Russian patent published in 2012 - IPC B23P6/00 C21D9/30 

FIELD: process engineering.

SUBSTANCE: invention relates to reconditioning large-size nitride-hardened crankshaft scored hollow journals by high-frequency current. Damaged journal, its cylindrical section and lubing orifices are machined to complete removal of nitride-hardened layer. Protectors are fitted into lubing orifices. Journal first hardening is performed by surface induction heating with revolving crankshaft. Journal second hardening is performed by surface induction heating with revolving crankshaft and journal preheating and further heating to hardening temperature in one revolution of crankshaft. Journal heated layer is cooled in every hardening by removing heat into journal body and webs in journal bend. Bearing fillets are cold-hardened to crankshaft beat not exceeding 0.05 mm and journal bearing seats are ground. Prior to heating, nitride-hardened layer is partially removed from journal inside as well as cast peel and cracks, if any, to fill is with mix of bentonite, metal shots and water.

EFFECT: higher efficiency and reliability.

3 cl, 1 dwg