1995 Fiscal Year Final Research Report Summary
Phase Transformation of Dynamically Recrystallized Austenite
| Project/Area Number |
06650795
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
Material processing/treatments
|
|---|
| Research Institution | The University of Electro-Communications (UEC) |
|---|
Principal Investigator |
SAKAI Taku UEC,Faculty of EC,Professor, 電気通信学部, 教授 (40017364)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
MIURA Hiromi UEC,Faculty of EC,Assistant Professor, 電気通信学部, 講師 (30219589)
除 洲 上海交通大学, 助教授
XU Zhou UEC,Faculty of EC,Associate Professor
|
|---|
| Project Period (FY) |
1994 – 1995
|
| Keywords | Hot Deformation / Dynamic recovery / Dynamic recrystallization / Dislocation substructure / Grain refinement / Diffusion transformation / Martensite transformation / Thermomechanical treatment |
|---|
| Research Abstract |
Static recovery and recrystallization taking place in dynamically recrystallized (DRX) matrices and the effect of them on the austenite to ferrite phase transformation were studied by using plain carbon, IF (interstitial free) and nickel alloy steels. The main results are summarized as follows.
1. Static restoration processes taking place in DRX matrices are metadynamic recovery and recrystallization as well as classical static recovery and recrystallization. The static softening curves under annealing of DRX matrices indicate three steps and do not go to full softening for a long period of annealing time. It is concluded that DRX grain structures can exist stably at high temperatures.
2. DRX grains are classified into the following categories ; dynamic nuclei, growing DRX grains which contain a dislocation density gradient and coarser DRX grains containing a uniformly distributed dislocation substructures. The growing DRX grains results in the three steps of softening and incomplete softening taking place in DRX matrices.
3. Static softening in DRX austenite of plain carbon steels is accerated initially by increasing of carbon content and, in contrast, the values of incomplete softening increase with carbon content.
4. Finer DRX austenite grains in IF steels lead to the evolution of finer ferrite grains compared with usual grains. Ferrite grains scarcely grow even after annealing of DRX austenite for a long period of time. These results from the stable existence of growing grains in DRX matrices.
5. Martensite transformation takes place rapidly and the microstructures transformed are more refined in DRX matrices compared with those in usual matrices.
|
