Title:
A manufacturing method of a forge crankshaft for multi-cylinder engines
Document Type and Number:
Japanese Patent JP6020692
Kind Code:
B2
Abstract:
A forged crankshaft (1) includes a carbon steel containing S, wherein in a portion corresponding to a machined outer circumferential surface of a shaft part such as journals (J), crank pins (P), a front part (Fr), and a flange (Fl), a ratio x/y of an area rate x of sulfide in a position (X) corresponding to a parting surface of a die for finish forging to an area rate y of sulfide in a position (Y) corresponding to a bottom of a die impression of the die for finish forging is equal to or lower than 1.5. The forged crankshaft (1) can avoid an occurrence of machined surface cracks on the journals (J) and the crank pins (P) after the outer circumferential surface is machined.
Inventors:
Hiroaki Tahira
Gold foundation
Junichi Okubo
Gold foundation
Junichi Okubo
Application Number:
JP2015195724A
Publication Date:
November 02, 2016
Filing Date:
October 01, 2015
Export Citation:
Assignee:
Nippon Steel & Sumitomo Metal Corporation
International Classes:
B21K1/08; B21J5/02; F16C3/08
Domestic Patent References:
| JP5169177A | ||||
| JP2012161819A | ||||
| JP2011110592A | ||||
| JP2003326332A |
Attorney, Agent or Firm:
Ascend Patent Business Corporation