Course of actions

Course of actions

Development of new process chain

The new forging sequence for a two-cylinder crankshaft has been developed by the help of Finite Element Analysis (FEA) software FORGE3. The new process chain consists of five forging stages: First, an upsetting operation, in which the part is flattened. Afterwards two flashless lateral extrusions, performed in closed dies. An induction reheating with a multidirectional forging operation followed. Finally, a flash reduced final forming was used to finish the crankshaft. The simulated flash ratio after the final forging operation was about 7 %, which is even better than the original aim of a flash ratio of 15 %.

Comparison of old and new process chain

Comparison of old and new process chain

Development of induction reheater

Due to the complicated work piece geometry, a complete new induction heating system for the reheating step was developed with the help of 3D numerical simulations. The shape of the induction coils are designed in a way to guarantee a quick positioning and an easy quick loading and unloading of the preformed crankshaft, while on the other hand the necessary electromagnetic field distribution inside the preformed work piece can be reached. Through intensive parameter studies the process temperature can be hold at admissible level. The abidance of these values and the verification of the simulation data were proven by experimental data.

  Cross-section of induction reheater (CAD-model) Prototype of induction reheater  
  Cross-section of induction reheater (CAD-model)
Source: ETP
Prototype of induction reheater
Source: ETP
 


Tests in industrial environment

The whole process chain was build up and tested at Omtaş Otomotiv Transmisyon Aksamı (OMTAS). After the preforming operations the parts were reheated by the induction reheater to compensate the temperature loss in the preforming operations and to spread the temperature again homogenously in the billet. This has been done to make the multidirectional forming operation as easy as possible. After the multidirectional forming, which was performed successful, the final forging of the part was performed also in an eccentric press with a maximum press force of 40,000 kN.

 

 

Results of the flash reduced forging process chain

 
  Video of forging trials   Results of the flash reduced forging process chain