Interrupted quenching in industrial processed for increased fatigue strength
| Reference number | |
| Coordinator | Swerea KIMAB AB |
| Funding from Vinnova | SEK 1 440 000 |
| Project duration | December 2011 - November 2013 |
| Status | Completed |
Purpose and goal
The aim of the project has been to introduce interrupted quenching for increased fatigue strength in a batch furnace after carburising and to test the potential of interrupted quenching after induction hardening. The goals have been to develop a method of interrupted quenching in batch furnace and to gain knowledge about the possibility of utilizing interrupted quenching also after induction hardening. The method for carburizing is developed. After induction hardening no positive effect on the fatigue strength was recorded.
Results and expected effects
Interrupted quenching has been introduced after carburising in a batch furnace. 10% improvement in fatigue strength was obtained against the expected 25%. After induction hardening no increased fatigue strength was obtained. This was probably due to that the surface temperature had dropped too far before the quenching was interrupted.
Approach and implementation
The set-up at both the carburizing and the induction hardening was to conduct heat treatment followed by fatigue testing and to evaluate the differences. To determine heat treatment cycles after induction hardening several calculations and dilatometer experiments were performed. Microstructures and residual stresses were measured.