Influence of the Martensite Volume Fraction on the Reciprocating Sliding Behavior of Ti-Nb Microalloyed Steel

2013 ◽  
Vol 57 (1) ◽  
pp. 146-155 ◽  
Author(s):  
W. Tuckart ◽  
D. Jenko ◽  
N. Fochesatto ◽  
F. Buezas ◽  
H. Lorusso ◽  
...  
2005 ◽  
Vol 475-479 ◽  
pp. 105-108 ◽  
Author(s):  
Guoan Chen ◽  
Wang Yue Yang ◽  
Shou Zhen Guo ◽  
Zu Qing Sun

By using TEM strain-induced precipitation of Nb(CN) during deformation of undercooled austenite was investigated in Nb-microalloyed steel. The results showed that at 1200°C all of Nb were dissolved and there were no Nb(CN) precipitates formed during cooling until down to 760°C; During deformation enhanced ferrite transformation Nb(CN) of dynamic precipitation required an incubation period, but compared with isothermal transformation it reduced significantly. Only when the strain increased to 0.69, Nb(CN) began to precipitate on dislocation nodes and grain boundaries. Furthermore the volume fraction of Nb(CN) precipitation increased with increasing strain but their coarsening wasn’t significant. Results showed that the measured grain size is in good agreement with the calculated value.


2011 ◽  
Author(s):  
Daavood Mirahmadi Khaki ◽  
Amir Abedi ◽  
Francisco Chinesta ◽  
Yvan Chastel ◽  
Mohamed El Mansori

2011 ◽  
Vol 228-229 ◽  
pp. 72-76
Author(s):  
J. H. Yang ◽  
Q. Y. Liu

Deformation dilatometry has been used to simulate controlled hot rolling followed by controlled cooling of a Nb microalloyed pipeline steels, the microstructure and transformation characteristics in the steel and the effect of deformation on transformation are studied. According to the results of both dilatometry measurements and microstructure observations, the continuous cooling transformation curves (CCT) of the tested steels are constructed. The results show that Nb content and deformation enhance the formation of acicular ferrite; the microstructure of the steel range from PF, QF to AF with increasing of cooling rates from 0.5 to 50°C /s in a two stages controlled rolling and the microstructure revolution is sensitive to cooling rates when it is lower than 5°C /s, however, when the cooling rate increasing further, the microstructure didn’t change very much but M/A constituents in matrix is refined and dispersed.


2021 ◽  
Author(s):  
Gamri Hamza ◽  
Allaoui Omar ◽  
Zidelmel Sami

Abstract The effect of the morphology and the martensite volume fraction on the microhardness, the tensile, the friction and the wear behavior of API X52 dual phase (DP) steel has been investigated. Three different heat treatments were used to develop dual phase steel with different morphologies and with different amounts of martensite: Intermediate Quenching Treatment/Water (IQ); Step Quenching Treatment (SQ) and direct quenching (DQ). Tribological tests are conducted on DP steels using a ball-on-disc configuration under normal load of 5 N and at a sliding speed of 4 cm/s were used to study the friction and wear behavior of treated samples. Results show that the ferrite–martensite morphology has a great influence on the mechanical properties of dual phase steel. The steel subjected to (IQ) treatment attain superior mechanical properties compared to the SQ and the DQ treatments. On the other hand, it is also found that the friction coefficient and the wear rate (volume loss) decrease when the hardness and the martensite volume fraction increase. The steel with fine fibrous martensite provide good wear resistance.


2018 ◽  
Vol 115 (3) ◽  
pp. 311 ◽  
Author(s):  
Ningbo Zhou ◽  
Fan Zhao ◽  
Yiqun Liu ◽  
Bo Jiang ◽  
Chaolei Zhang ◽  
...  

The transformation behavior and intragranular ferrite formation in V–Ti microalloyed steel with a nitrogen content of 0.005 wt.% and 0.015 wt.% are studied by the DIL 805A dilatometer. The results show that increasing the nitrogen content has no significant effect on AC1, AC3and MStemperature. However, the continuous cooling transformation (CCT) diagrams are shifted to left side. The minimum cooling rates of bainitc and martensitic transformation are increased from 3 °C/s to 5 °C/s and from 5 °C/s to 10 °C/s, respectively. (Ti, V)(C, N) particles on MnS is the nuclei of intragranular ferrite, and (1 0 0)(Ti, V)(C, N)and (1̅ 0 1̅α) are just misoriented by 6.7°. With the increase of nitrogen content, the number of intragranular ferrite is increased from 73 to 170 per · mm2. The volume fraction of intragranular ferrite is increased from 0.23%∼0.79% to 0.79%∼4.6% at cooling rate of 1 °C/s∼0.1 °C/s. According to the industrial production experiment, the toughness of forging crankshaft is improved by increasing the nitrogen content. It is benefit for achieving fair matching of high strength and high toughness of crankshaft.


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