Continuous Cooling Transformation Behavior of High Carbon Pearlitic Steel

2022 ◽  
Vol 905 ◽  
pp. 83-87
Author(s):  
Lu Lu Feng ◽  
Wei Wen Qiao ◽  
Jian Sun ◽  
De Fa Li ◽  
Ping Ping Li ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Vickers Hardness ◽  
Hardness Test ◽  
Pearlitic Steel ◽  
Transformation Behavior ◽  
High Carbon ◽  
Continuous Cooling Transformation ◽  
Continuous Cooling ◽  
Test Steel ◽  
Lamellar Pearlite

The continuous cooling transformation behavior of high-carbon pearlitic steel was studied by employing optical microscopy, scanning electron microscopy, and the Vickers hardness test. The results show that the microstructure of the test steel is composed of proeutectoid cementite and lamellar pearlite in the cooling rate range of 0.05–2 °C/s and lamellar pearlite in the range of 2–5 °C/s. Further, martensite appears at 10 °C/s. With the increase in the cooling rate, the Vickers hardness of the test steel first decreases and then increases. In the industrial production of high-carbon pearlite steel, the formation of proeutectoid cementite at a low cooling rate needs to be avoided, and at the same time, the formation of martensite and other brittle-phase at a high cooling rate needs to be avoided.

Effect of Chromium and Vanadium Contents on Continuous Cooling Transformation Behavior of Multi-Component White Cast Iron

2010 ◽  
Vol 457 ◽  
pp. 237-242 ◽  
Author(s):  
Yuzo Yokomizo ◽  
Kaoru Yamamoto ◽  
Nobuya Sasaguri ◽  
Yasuhiro Matsubara
Keyword(s):  
Cooling Rate ◽  
White Cast Iron ◽  
The Other ◽  
Transformation Behavior ◽  
Bainite Transformation ◽  
Cast Irons ◽  
Continuous Cooling Transformation ◽  
Critical Cooling Rate ◽  
Continuous Cooling ◽  
Cr Content

In this study, the multi-component white cast irons with 5wt% of Mo, W, 2 wt% of C, Co each and varying Cr content from 1 to 9 wt% and V content from 3 to 9 wt% independently were employed and effect of Cr and V contents on the behavior of continuous cooling transformation (CCT) was investigated. When the Cr content increases to 5wt%, the critical cooling rate of pearlite transformation (VC-P) does not change much, but the VC-P decreases gradually as the Cr content is increased over 5 wt%. The critical cooling rate of bainite transformation (VC-B) increases with an increase in the Cr content. In the case of V effect, on the other hand, the VC-P decreases as the V content increases. However, the VC-B decreases with an increase in the V content up to 4mass%, but over 4wt%V, it increases, and at 9wt%V, the precipitation of ferrite phase occurred. Ms temperature decreases continuously as the Cr content increases to 5wt%, and then increases. As the V content increases, Ms temperature rises gradually. In the case that Mf point appears, the Mf temperature goes up with an increase in the Cr and V contents.

Continuous Cooling Transformation Behavior of a Ti Addition Steel

2014 ◽  
Vol 556-562 ◽  
pp. 480-483
Author(s):  
Chen Zhang ◽  
Guang Xu ◽  
Zhang Wei Hu ◽  
Hai Lin Yang
Keyword(s):  
Phase Transformation ◽  
Solid State ◽  
Cooling Rate ◽  
Transformation Behavior ◽  
Cooling Rates ◽  
Continuous Cooling Transformation ◽  
Continuous Cooling ◽  
Cct Curve ◽  
Solid State Phase Transformation ◽  
Ti Addition

The continuous cooling transformation (CCT) behavior of a Ti attached steel was studied through thermal simulation tests, and the influences of different cooling rates on the microstructure and transformation were investigated. The results show that the microstructure changes with the cooling rate, and the CCT curve of studied steel is plotted, which indicates that the solid-state phase transformation mainly consists of four regions. The CCT diagram made it possible to predict the microstructures of studied steel with different cooling rates.

Continuous Cooling Transformation Behavior of Vercooling Austenite of Low Carbon-Manganese Steel

2011 ◽  
Vol 418-420 ◽  
pp. 523-527
Author(s):  
Li Wei Duan ◽  
Yun Li Feng ◽  
Xue Jing Qi
Keyword(s):  
Cooling Rate ◽  
Manganese Steel ◽  
Accelerated Cooling ◽  
Low Carbon ◽  
Transformation Behavior ◽  
Continuous Cooling Transformation ◽  
Continuous Cooling ◽  
Transformation Rules ◽  
Experimental Deformation ◽  
Gleeble 3500

Continuous cooling transformation rules of Low Carbon-Manganese Steel were investigated on Gleeble-3500 thermomechanical simulator. The study indicates that as cooling rate increases, Ar3 loweres and Ar1 behaves similarly but much slowly. The microstructure composes of dominant ferrite and some pearlite. As cooling rate enhances, the ferritic grain become finer, when cooling rate is up to 30°C/s, a little bainite appears. With the increasing of cooling rate the dimension of ferrite decreases. Under the experimental deformation conditions, ferritic grain refinement gets weak when the cooling rate is greater than or equal to 20°C/s. Therefore, with a certain strain, ferritic grain can refined to some degree by accelerated cooling.

Continuous Cooling Transformation of Overcooling Austenite and Structure Evolution of Si Steel

2013 ◽  
Vol 652-654 ◽  
pp. 947-951
Author(s):  
Hui Li ◽  
Yun Li Feng ◽  
Da Qiang Cang ◽  
Meng Song
Keyword(s):  
Phase Transformation ◽  
Cooling Rate ◽  
Optical Microscope ◽  
Structure Evolution ◽  
Upward Trend ◽  
Continuous Cooling Transformation ◽  
Continuous Cooling ◽  
Hardness Tester ◽  
Gleeble 3500 ◽  
Evolution Of Microstructure

The static continuous cooling transformation (CCT)curves of 3.15 Si-0.036 C-0.21 Mn-0.008 S-0.008 N-0.022 Al are measured on Gleeble-3500 thermal mechanical simulator, the evolution of microstructure and the tendency of hardness are investigated by optical microscope (OM) and hardness tester. The results show that there is no evident change in microstructure which mainly are ferrite and little pearlite under different cooling rates, but the transition temperature of ferrite is gradually reduced with the increase of cooling rate. When the cooling rate is increased from 0.5°C/s to 20°C/s, the ending temperatures of phase transformation are decreased by 118°C, when cooling rate reaches to 10, Widmanstatten ferrite appears. The hardness of the steel turns out gradual upward trend with the increase of cooling rate.

Continuous Cooling Transformation Behavior of a Microalloyed Spring Steel

2003 ◽  
Author(s):  
J. D. Boyd ◽  
P. Zhao ◽  
J. Panatarotto ◽  
G. Nadkarni ◽  
T.G. Oakwood
Keyword(s):  
Spring Steel ◽  
Transformation Behavior ◽  
Continuous Cooling Transformation ◽  
Continuous Cooling

Influence of Chromium Content and Prior Deformation on the Continuous Cooling Transformation Diagram of Low-Carbon Bainitic Steels

2020 ◽  
Vol 835 ◽  
pp. 58-67
Author(s):  
Mohammed Ali ◽  
Antti J. Kaijalainen ◽  
Jaakko Hannula ◽  
David Porter ◽  
Jukka I. Kömi
Keyword(s):  
Cooling Rate ◽  
Hot Deformation ◽  
Laser Scanning ◽  
Chromium Content ◽  
Bainitic Ferrite ◽  
Granular Bainite ◽  
Low Carbon ◽  
Cooling Rates ◽  
Continuous Cooling Transformation ◽  
Continuous Cooling

The effect of chromium content and prior hot deformation of the austenite on the continuous cooling transformation (CCT) diagram of a newly developed low-carbon bainitic steel has been studied using dilatometer measurements conducted on a Gleeble 3800 simulator with cooling rates ranging from 2-80 °C/s. After austenitization at 1100 °C, specimens were either cooled without strain or given 0.6 strain at 880 °C prior to dilatometer measurements. The resultant microstructures have been studied using laser scanning confocal microscopy, scanning electron microscopy and macrohardness measurements. CCT and deformation continuous cooling transformation (DCCT) diagrams were constructed based on the dilatation curves, final microstructures and hardness values. Depending on the cooling rate, the microstructures of the investigated steels after cooling from the austenite region consist of one or more of the following microstructural components: lath-like upper bainite, i.e. bainitic ferrite (BF), granular bainite (GB), polygonal ferrite (PF) and pearlite (P). The proportion of BF to GB as well as the hardness of the transformation products decreased with decreasing cooling rate. The cooling rate at which PF starts to appear depends on the steel composition. With both undeformed and deformed austenite, increasing the chromium content led to higher hardenability and refinement of the microstructure, promoting the formation of BF and shifting the ferrite start curve to lower cooling rates. Prior hot deformation shifted the transformation curves to shorter times and higher temperatures and led to a reduction in hardness at the low cooling rates through the promotion of ferrite formation.

Continuous Cooling Phase Transformation Rule of 20CrMnTi Low-Carbon Alloy Steel

2019 ◽  
Vol 944 ◽  
pp. 303-312
Author(s):  
Li Zhang Li ◽  
He Wei ◽  
Lin Lin Liao ◽  
Yin Li Chen ◽  
Hai Feng Yan ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Cooling Rate ◽  
Vickers Hardness ◽  
Rolling Process ◽  
Transformation Rule ◽  
Low Carbon ◽  
Continuous Cooling ◽  
Starting Time ◽  
Ferrite Transformation ◽  
The Ideal

Gear steel is a ferritic steel. In the rolling process, the ideal structure is ferrite + pearlite, and bainite or martensite is not expected. However, due to the high alloy content, the hardenability is good, and the bainite or martensite structure is very likely to be generated upon cooling after rolling. In this paper, phase transformation rules during continuous cooling of 20CrMnTi with and without deformation were studied to guide the avoidance of the appearance of bainite or martensite in steel. A combined method of dilatometry and metallography was adopted in the experiments, and the dilatometer DIL805A and thermo-simulation Gleeble3500 were used. Both dynamic and static continuous cooling transformation (CCT) diagrams were drawn by using the software Origin. The causes of those changes in starting temperature, finishing temperature, starting time and transformation duration in ferrite-pearlite phase transformation were analyzed, and the change in Vickers hardness of samples with different cooling rate was discussed. The results indicate that with different cooling rate, there are three phase transformation zones: ferrite-pearlite, bainite and martensite. Deformation of austenite accelerates the occurrence of transformation obviously and moves CCT curve to left and up direction. When the cooling rate is lower than 1 °C/s, the phases in samples are mainly ferrite and pearlite, which is the ideal microstructure of experimental steel. As the cooling rate increases, starting temperature of ferrite transformation in steel decreases, starting time reduces, transformation duration gradually decreases, and the Vickers hardness of samples increases. Under the cooling rate of 0.5 °C/s, ferrite transformation in deformed sample starts at 751.67 °C, ferrite-pearlite phase transformation lasts 167.9 s, and Vickers hardness of sample is 183.4 HV.

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