Effect of Different Strain on Microstructure Evolution of Medium Carbon Steel

2013 ◽  
Vol 652-654 ◽  
pp. 923-928 ◽  
Author(s):  
Peng Tian ◽  
Zhi Yong Zhong ◽  
Wei Jun Hui ◽  
Rui Guo Bai ◽  
Xing Li Zhang
Keyword(s):  
Carbon Steel ◽  
Microstructure Evolution ◽  
Simulation Experiment ◽  
Volume Fraction ◽  
True Strain ◽  
Medium Carbon Steel ◽  
Controlled Cooling ◽  
Medium Carbon ◽  
The Right ◽  
Equilibrium Content

Uniaxial hot compression simulation experiment at 700°C with different true strain was carried out to study the microstructure evolution of medium carbon steel, the predominant mechanism on the cementite softening has been explored, the experimental results show that the volume fraction of deformation induced ferrite (DIF) increased with increasing true strain and even exceeds the equilibrium content. With the increase of DIF, more and more carbon atoms congregated in the boundaries such as the interface of DIF and the interphase of DIF/deformation austenite. Carbon congregation provides the right carbon content and the optimized microstructure for divorced decomposition during the process of controlled cooling. Therefore spherical or rod-like cementite and degenerated pearlite can be obtained.

The Effect of Controlled Rolling and Cooling on the Microstructure Evolution of Boron Microalloyed Medium-Carbon Steel

2010 ◽  
Vol 146-147 ◽  
pp. 1305-1309
Author(s):  
Wu Hua Yuan ◽  
Qiang Fu ◽  
Heng Zhou
Keyword(s):  
Carbon Steel ◽  
Grain Boundaries ◽  
Microstructure Evolution ◽  
Volume Fraction ◽  
Controlled Rolling ◽  
Medium Carbon Steel ◽  
Rolling Temperature ◽  
Compression Tests ◽  
Medium Carbon ◽  
Average Grain Size

The processes of controlled rolling and cooling were simulated using hot compression tests on a Gleeble 1500 simulator with boron microalloyed medium-carbon steel. Effects of finish rolling temperature ranging from 760oC to 840oC and loop-laying temperature ranging from 660oC to 700oC on the microstructure evolution were studied. Experimental observations show that the average grain size of ferrite decreases while the volume fractions of ferrite and spheroidized pearlite increase when lowering rolling temperature. The maximum volume fraction of ferrite (62%) reached in our tests was obtained in the specimen whose rolling temperature and loop-laying temperature was 760oC and 700oC respectively. Excessive precipitation of the ferrite resulted in the carbon enrichment on some grain boundaries. Boron addition is effective to improve hot plastic deformation ability by removing nitrogen from AlN to form coarse BN particles on the grain boundaries.

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