EFFECT OF CONTROLLED ROLLING PROCESSING ON NANOMETER-SIZED CARBONITRIDE OF Ti-Mo FERRITE MATRIX MICROALLOYED STEEL

2012 ◽  
Vol 48 (12) ◽  
pp. 1415 ◽  
Author(s):  
Chaofan SUN ◽  
Qingwu CAI ◽  
Huibin WU ◽  
Hongyan MAO ◽  
Hongzhen CHEN
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.


2018 ◽  
Vol 926 ◽  
pp. 3-10
Author(s):  
Zhi Chen Yu ◽  
Zhen Li Mi ◽  
Qing Wu Cai ◽  
Jin Guo ◽  
Na Gong

The size and distribution of nanoscale precipitate particles in Ti-Mo ferrite matrix microalloyed steel under three different final rapid cooling temperatures were studied by scanning electron microscopy(SEM), transmission electron microscope(TEM) and microhardness test. The results show that the interphase precipitation could be weakened by the excessive final rapid cooling temperature. A higher supersaturated solid solubility and high-density dislocation in ferrite matrix can be obtained under a relatively lower final rapid cooling temperature, which makes it easier to precipitate in ferrite. The related thermodynamic analysis indicated that the precipitation behavior was influenced by the final rapid cooling temperature during austenite/ferrite region. It is not conducive to get a large amount of small size precipitates in Ti-Mo ferrite matrix microalloyed steel when the final rapid cooling temperature is too high or low.


2010 ◽  
Vol 129-131 ◽  
pp. 1022-1028
Author(s):  
Daavood Mirahmadi Khaki ◽  
A. Akbarzadeh ◽  
Amir Abedi

Thermo mechanical processing and controlled rolling of microalloyed steel sheets are affected by several factors. In this investigation, finishing temperature of rolling which is considered as the most effective parameters on the final mechanical properties of hot rolled products has been studied. For this purpose, three different finishing temperatures of 950, 900 and 850 °C below the non-recrystallization temperature and one temperature of 800 °C in the intercritical range were chosen. It is observed that decreasing the finishing temperature causes increase of strength and decrease of total elongation. This is accompanied by more grain refinement of microstructure and the morphology was changed from polygonal ferrite to acicular one. Findings of this research provide suitable connection among finishing temperature, microstructural features, and mechanical properties of hot rolled Nb-microalloyed steel sheets.


2016 ◽  
Vol 879 ◽  
pp. 2066-2071 ◽  
Author(s):  
Zhao Dong Wang ◽  
Bin Wang ◽  
Yan Mei Li ◽  
Bing Xing Wang ◽  
Guo Dong Wang

We describe here the relationship between electron microscopy and mechanical property studies in industrially processed titanium bearing microalloyed steel plates that involved processing using the recently developed ultrafast cooling (UFC) approach. Given that the segregation of manganese is generally responsible for microstructural banding in low-alloy steels, which can deteriorate the tensile property in the direction of thickness, the manganese-content was reduced by ~0.6-0.8% with the objective to obtain uniform microstructure across the thickness of the steel plate. Besides, non-uniform distribution of accelerated cooling along the thickness direction also leads to inhomogeneous microstructure across the plate thickness. In order to obtain near-uniform microstructure and similar mechanical properties from the surface to the center of plate, fast and effective cooling process is necessary. In this regard, refined and uniform microstructure that was free of microstructural banding was obtained via UFC process across the plate thickness, with strict control and faster cooling rate on the run-out table. Furthermore, grain refinement and random precipitation in the ferrite matrix contributed ~100 MPa toward yield strength. The study underscores the potential of processing medium and heavy plates of titanium bearing microalloyed steels plates with uniform and refined microstructure across the thickness via thermo-mechanical controlled processing (TMCP) involving UFC.


2012 ◽  
Vol 706-709 ◽  
pp. 1624-1629 ◽  
Author(s):  
Dmitry Ringinen ◽  
Nicolay G. Kolbasnikov ◽  
Oleg G. Zotov ◽  
Andrey Rudskoy

In this paper we have investigated the possibility of increasing the complex mechanical properties of steel strength category X90 by refinement the structure of hot and warm deformation. Were carried out tests to determine the critical points of recrystallization and built thermokinetic curves of austenite decomposition. After that, for produce disperse ferrite in samples has been applied to the processing mode, which is exactly the same mode of controlled rolling, then, to obtain nanoscale state of the metal deformed at temperatures of bainite transformation with varying degrees of deformation at different temperatures. It was shown that the dispersion and morphology of the structure and, consequently, the mechanical properties vary depending on temperature and strain, and samples show satisfactory ductility at high strength.


1988 ◽  
Vol 38 (4) ◽  
pp. 380-383
Author(s):  
V. Jurko ◽  
B. štefan ◽  
F. Kováč ◽  
K. Pelikán

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