Volume 7, Number 1 (winter 2010 2010)                   IJMSE 2010, 7(1): 7-14 | Back to browse issues page


XML Print


Download citation:
BibTeX | RIS | EndNote | Medlars | ProCite | Reference Manager | RefWorks
Send citation to:

M. Esmailian. THE EFFECT OF COOLING RATE AND AUSTENITE GRAIN SIZE ON THE AUSTENITE TO FERRITE TRANSFORMATION TEMPERATURE AND DIFFERENT FERRITE MORPHOLOGIES IN MICROALLOYED STEELS. IJMSE. 2010; 7 (1) :7-14
URL: http://ijmse.iust.ac.ir/article-1-224-en.html

Abstract:   (9664 Views)

Abstract:

transformation temperature and different ferrite morphologies in one Nb-microalloyed (HSLA) steel has been

investigated. Three different austenite grain sizes were selected and cooled at two different cooling rates for obtaining

austenite to ferrite transformation temperature. Moreover, samples with specific austenite grain size have been

quenched, partially, for investigation on the microstructural evolution.

In order to assess the influence of austenite grain size on the ferrite transformation temperature, a temperature

differences method (TDM) is established and found to be a good way for detection of austenite to ferrite, pearlite and

sometimes other ferrite morphologies transformation temperatures.

The results obtained in this way show that increasing of austenite grain size and cooling rate has a significant influence

on decreasing of the ferrite transformation temperature.

Micrographs of different ferrite morphologies show that at high temperatures, where diffusion rates are higher, grain

boundary ferrite nucleates. As the temperature is lowered and the driving force for ferrite formation increases,

intragranular sites inside the austenite grains become operative as nucleation sites and suppress the grain boundary

ferrite growth. The results indicate that increasing the austenite grain size increases the rate and volume fraction of

intragranular ferrite in two different cooling rates. Moreover, by increasing of cooling rate, the austenite to ferrite

transformation temperature decreases and volume fraction of intragranular ferrite increases.

The effect of different austenite grain size and different cooling rates on the austenite to ferrite
Full-Text [PDF 960 kb]   (6847 Downloads)    
Type of Study: Research paper |

Add your comments about this article : Your username or email:
Write the security code in the box

Send email to the article author


© 2016 All Rights Reserved | Iranian Journal of Materials Science and Engineering

Designed & Developed by : Yektaweb