Microstructure and Mechanical Properties of 60Si2Mn Steel after Austenite Inverse Phase Transformation by Sub-Temperature Quenching

2011 ◽  
Vol 399-401 ◽  
pp. 228-232
Author(s):  
An Ming Li ◽  
Meng Juan Hu

Microstructure and mechanical properties of 60Si2Mn steel by 870 °C prequenched and second sub-temperature quenching was studied. The results showed that the hardness of the 60Si2Mn steel first increased and then decreased with increasing second sub-temperature quenching temperature, and the highest hardness was obtained when sub-temperature quenching temperature was 800 °C.The sample after second sub-temperature quenching was composed of martensite and a little ferrite phase. The abundance of ferrite phase decreased with the increase in second sub-temperature quenching temperature. Fine martensite was obtained by second sub-temperature quenching, which may be relate to the grain refinement of austenitic phase and austenitic nucleation sites. The mechanical properties of the 60Si2Mn steel after 870 °C prequenching and second sub-temperature quenching are better than that of conventional samples after 870 °C quenching.

2011 ◽  
Vol 194-196 ◽  
pp. 89-94
Author(s):  
An Ming Li ◽  
Meng Juan Hu

The influence of sub-temperature quenching temperature on the strength and hardness of 65Mn steel during austenite inverse phase transformation is studied and the microstructure and property are analyzed. The results showed that in the range of 760~810°C , the strength and hardness of the 65Mn steel second sub-temperature quenched increased with quenching temperature increasing, reached the highest strength and hardness at 790°C quenching and then began to decrease. A small number of ferrite and ferrite dual-phase structure existed in martensite when quenching temperature was low. Fine martensite was obtained by second sub-temperature quenching due to the smaller austenitic crystal grain and austenitic nucleation sites. The mechanical properties of samples second sub-temperature quenched are better than that of conventional samples 830°C once quenched.


2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Tiebao Wang ◽  
Chunxiang Cui ◽  
Kuo Jia ◽  
Lichen Zhao

The nanostructured Fe-V-Nb master alloy was prepared in vacuum rapid quenching furnace and then was added in the steel melts as modificators before casting. Next, the effects of the nanostructured Fe-V-Nb modificators on the microstructure and mechanical properties of the steel were studied. The results show that the grain size of the steel has been effectively refined, which is mainly because the dispersed nanoscale particles can produce more nucleation sites during the solidification of the liquid steel. Tensile properties and fracture morphology reveal that the yield strength and toughness of the steel modified by nanostructured Fe-V-Nb modificators are better than that of the microalloyed steel. TEM analysis shows that vanadium and niobium in the modificators exist in the form of (V, Nb) C which effectively increases the nucleation rate and leads to better mechanical properties of the steel.


2013 ◽  
Vol 589-590 ◽  
pp. 572-577 ◽  
Author(s):  
Hua He Liu ◽  
Han Lian Liu ◽  
Chuan Zhen Huang ◽  
Bin Zou ◽  
Ya Cong Chai

Al2O3-MgO, Al2O3-Y2O3 and Al2O3-MgO-Y2O3 composite ceramics were fabricated respectively by hot-press sintering technique. With the analysis of the mechanical properties and microstructure, it was found that single additive MgO could be more favorable to the grains’ refinement and densification than Y2O3; the composite additive including both MgO and Y2O3 was better than single additive MgO or Y2O3, because their interactions could improve the mechanical properties of the Al2O3 ceramics; The sintering temperature could be reduced by adding the suitable amount of composite additives.


2014 ◽  
Vol 5 ◽  
pp. 1368-1375 ◽  
Author(s):  
C.G. Shivaprasad ◽  
S. Narendranath ◽  
Vijay Desai ◽  
Sujeeth Swami ◽  
M.S. Ganesha Prasad

2001 ◽  
Vol 21 (12) ◽  
pp. 2179-2183 ◽  
Author(s):  
Jian-Feng Yang ◽  
Tatsuki Ohji ◽  
Tohru Sekino ◽  
Chun-Liang Li ◽  
Koichi Niihara

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 978 ◽  
Author(s):  
Pengfei Wang ◽  
Zhaodong Li ◽  
Guobiao Lin ◽  
Shitong Zhou ◽  
Caifu Yang ◽  
...  

Steels used for high-speed train wheels require a combination of high strength, toughness, and wear resistance. In 0.54% C-0.9% Si wheel steel, the addition of 0.075 or 0.12 wt % V can refine grains and increase the ferrite content and toughness, although the influence on the microstructure and toughness is complex and poorly understood. We investigated the effect of 0.03, 0.12, and 0.23 wt % V on the microstructure and mechanical properties of medium-carbon steels (0.54% C-0.9% Si) for train wheels. As the V content increased, the precipitation strengthening increased, whereas the grain refinement initially increased, and then it remained unchanged. The increase in strength and hardness was mainly due to V(C,N) precipitation strengthening. Increasing the V content to 0.12 wt % refined the austenite grain size and pearlite block size, and increased the density of high-angle ferrite boundaries and ferrite volume fraction. The grain refinement improved the impact toughness. However, the impact toughness then reduced as the V content was increased to 0.23 wt %, because grain refinement did not further increase, whereas precipitation strengthening and ferrite hardening occurred.


2010 ◽  
Vol 105-106 ◽  
pp. 27-30 ◽  
Author(s):  
Wei Ru Zhang ◽  
Feng Sun ◽  
Ting Yan Tian ◽  
Xiang Hong Teng ◽  
Min Chao Ru ◽  
...  

Silicon nitride ceramics were prepared by gas pressure sintering (GPS) with different sintering additives, including La2O3, Sm2O3 and Al2O3. Effect of sintering additives on the phase-transformation, microstructure and mechanical properties of porous silicon nitride ceramics was investigated. The results show that the reaction of sintering additives each other and with SiO2 had key effects on the phase-transformation, grain growing and grain boundaries. With 9MPa N2 atmosphere pressure, holding 1h at 1850°C, adding 10wt% one of the La2O3, Sm2O3, Al2O3, porous silicon nitride was prepared and the relative density was 78%, 72%, 85% respectively. The flexural strength was less than 500MPa, and the fracture toughness was less than 4.8MPam1/2. Dropping compounds sintering additives, such as La2O3+Al2O3, Sm2O3+Al2O3 effectively improves the sintering and mechanical properties. The relative density was 99.2% and 98.7% with 10wt% compounds sintering additives. The grain ratio of length to diameter was up to 1:8. The flexural strength was more than 900MPa, and the fracture toughness was more than 8.9MPam1/2.


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