scholarly journals Measurement of Continuous Cooling Transformation Curve and High Temperature Mechanical Properties for 12Mn Steel

2021 ◽  
Author(s):  
Sheng tao Qiu ◽  
Jun Wei
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Cooling Rate ◽  
Hardness Measurement ◽  
Continuous Cooling Transformation ◽  
Continuous Cooling ◽  
High Temperature Mechanical Properties ◽  
Transformation Curve ◽  
Reduction Of Area ◽  
Fast Increase

The dilatometer curves of continuous cooling transformation of 12Mn steel were measured with Formastor-FⅡthermal mechanical simulator．The steel's undercooled austenite phase continuous cooling transformation curves ( CCT curves) were established by means of the dilatometer method and the metallographic-hardness measurement method． The effect of cooling rate on microstructure and hardness of the steel was studied． CCT curve of test steel was simulated by JMatPro. The results show that the Ac1 and Ac3 of the experimental steel are 692 ℃ and 855 ℃ ; the microstructure obtained is made of ferrite，pearlite and bainite．The ferrite transformation and pearlite transformation occur at a slower cooling rate，in which the ferrite is dominant. When the cooling rate is greater than 4.25 ℃ / s bainite transformation happens．As the cooling rate increases，microstructure or grains become finer．The hardness of the tested steel with increasing cooling rate shows a trend of first fast increase and soon decrease．The simulation results are consistent with the measured CCT law. The high temperature mechanical properties of 12mn steel round billet were tested by gleeble-1500d thermal / mechanical simulator. The tensile strength, reduction of area and stress-strain curves of the billet were obtained in the range of 600-1300 ℃.

Effect of Rare Earth on High Temperature Properties of Heat-Resisting Steel

2012 ◽  
Vol 557-559 ◽  
pp. 108-111
Author(s):  
Xiao Liu ◽  
Hu Fei Zhang
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Rare Earth ◽  
High Temperature ◽  
Oxidation Resistance ◽  
Cleavage Fracture ◽  
Oxidation Rate ◽  
High Temperature Mechanical Properties ◽  
Dimple Fracture ◽  
Reduction Of Area

The oxidation resistance and high temperature mechanical properties of FeCrNi heat-resisting steel are analyzed and studied. The results show that the oxidation resistance of the heat-resisting steel is improved remarkably after adding RE. The value of oxidation rate of Sample 1 (without adding RE) is 1.71 times higher than Sample 2, respectively at 1423K. And the value of oxidation rate of Sample 1 is 1.4 times higher than Sample 2, respectively at 1473K. The fracture mode of heat-resisting stainless steel is typical cleavage fracture, but dimple fracture after adding RE into the steel. The high temperature mechanical properties of heat-resisting steel is improved obviously by RE. In comparison with heat-resisting stainless steel without RE, the reduction of area of heat-resisting stainless steel with RE is increased 26.27% at 1123K.

scholarly journals Continuous Cooling Transformation of Under-Cooled Austenite of SXQ500/550DZ35 Hydropower Steel

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1562
Author(s):  
Zhenglei Tang ◽  
Ran Guo ◽  
Yang Zhang ◽  
Zhen Liu ◽  
Yuezhang Lu ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Hardness Measurement ◽  
Cooling Rates ◽  
Continuous Cooling Transformation ◽  
Continuous Cooling ◽  
Continuous Cooling Transformation Diagrams ◽  
Transformation Diagrams ◽  
Hot Rolled ◽  
Vickers Hardness Measurement ◽  
Undercooled Austenite

The expansion curves of the continuous cooling transformation of undercooled austenite of SXQ500/550DZ35 hydropower steel at different heating temperatures and cooling rates were measured by use of a DIL805A dilatometer. Combined with metallography and Vickers hardness measurement, the continuous cooling transformation diagrams (CCT) of the studied steel under two different states were determined. The results show that in the first group of tests, after the hot-rolled specimens were austenitized at 920 °C, when the cooling rate was below 1 °C·s−1, the microstructure was composed of ferrite (F), pearlite (P) and bainite (B). With the cooling rates between 1 °C·s−1 and 5 °C·s−1, the microstructure was mainly bainite, and martensite (M) formed as the cooling rate reached 5 °C·s−1. When the cooling rate was up to 10 °C·s−1, the microstructure was completely martensite and the hardness value increased significantly. In the second group of tests, after the hot-rolled specimens were quenched at 920 °C and then heated at an intercritical temperature of 830 °C, in comparison with the first group of tests, and except for additional undissolved ferrites in each cooling rate range, the other microstructure types were basically the same. Due to the existence of undissolved ferrite, the microstructures of the specimens heated at intercritical temperatures were much finer, and the toughness values at low temperatures were better.

Hot Deformation Behavior of V-Microalloyed Steel

2010 ◽  
Vol 654-656 ◽  
pp. 310-313
Author(s):  
An Chao Ren ◽  
Yu Ji ◽  
Gui Feng Zhou ◽  
Ze Xi Yuan ◽  
Bin Han ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Cooling Rate ◽  
Deformation Temperature ◽  
Rail Steel ◽  
Compression Tests ◽  
Double Pass ◽  
Continuous Cooling Transformation ◽  
Continuous Cooling ◽  
Softening Behavior ◽  
Transformation Curve

The dilatation curves of continuous cooling transformation at different cooling rates were determined for U75V rail steel by THERMECMASTOR-Z thermal simulator, and continuous cooling transformation curve was obtained. The influence of cooling rate on microstructure and hardness was studied. The softening behavior after isothermal deformation in the austenite region 850-1000°C but before the second pass was also studied by double-pass compression tests. The results show that the product of austenite decomposition was pearlite when the cooling rate was lower than 10°C. Troostite and martensite were gained at the cooling rate of 10°C•s-1. Only martensite was obtained when the cooling rate was in the range of 10-50°C•s-1. The hardness of the steel increased with the increase of cooling rate. Under the condition of 30% deformation and 3s-1 deformation rate, the relaxation time for completing recrystallization was shorter than 100s when the deformation temperature was higher than 1000°C. When the deformation temperature was lower than 880°C, full recrystallization was difficult to achieve even if the relaxation time was extended.

Study on High-Temperature Mechanical Properties of SPHC Steel Produced by CSP Technology

2015 ◽  
Vol 1095 ◽  
pp. 188-192 ◽  
Author(s):  
Qi Chun Peng ◽  
Jia Jie Wang ◽  
Zhi Bo Tong
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Strain Rate ◽  
Testing Temperature ◽  
Percentage Reduction ◽  
Compact Strip Production ◽  
High Temperature Mechanical Properties ◽  
Sphc Steel ◽  
Reduction Of Area ◽  
Strip Production

The high-temperature mechanical properties of SPHC steel produced by compact strip production (CSP) process were tested on Gleeble thermal simulator under different temperature conditions. The results show that: at the strain rate of 1×10-3s-1,the SPHC steel has three brittleness temperature zones within the range from 650°C to 1200°C;the percentage reduction of area of the tested steel are all above 60% within the range from 950°C to 1150°C,thus the steel has good high temperature plasticity; the percentage reduction of area decreases rapidly when the testing temperature is under 900°C and the minimum percentage reduction of area is only about 41.78% at 800°C.

Continuous Cooling Transformation Behavior of X70 Pipeline Steel

2013 ◽  
Vol 690-693 ◽  
pp. 2205-2209
Author(s):  
Hong Mei Yang
Keyword(s):  
Cooling Rate ◽  
Hot Deformation ◽  
Acicular Ferrite ◽  
Transformation Temperature ◽  
Pipeline Steel ◽  
Continuous Cooling Transformation ◽  
X70 Pipeline Steel ◽  
Continuous Cooling ◽  
Transformation Curve ◽  
Continuous Cooling Transformation Curve

The continuous cooling transformation behaviors were researched on X70 pipeline steel through two pass deformation and non-deformed austenite using Gleeble-3500 thermal mechanical simulator, and static continuous cooling transformation curve and dynamic continuous cooling transformation curve were measured through thermal dilation method and metallographic method. The influence of cooling rate and deformation parameters on microstructure was analyzed. The results show that the hot deformation accelerates the acicular ferrite and polygonal ferrite phase transformation, increases the starting transformation temperature and the finishing transformation temperature significantly, and shifts the CCT curve moving upward to the left side corner. Acicular ferrite is obtained in practice using accelerated cooling rate after deformation Acicular ferrite can be obtained in wider range of cooling rates, and microstructure and island structure is finer through hot deformation.

Dynamic CCT Curve of Hot Deformation Austenite in 55SiCr Steel

2012 ◽  
Vol 548 ◽  
pp. 225-228
Author(s):  
Yong Jun Zhang ◽  
Chuan Da Cui ◽  
Jing Tao Han
Keyword(s):  
Cooling Rate ◽  
Hot Deformation ◽  
Transformation Products ◽  
Thermal Simulation ◽  
Continuous Cooling Transformation ◽  
Continuous Cooling ◽  
Microstructure Transformation ◽  
Cct Curve ◽  
Rate Form ◽  
Transformation Curve

The CCT (Continuous Cooling Transformation) curve of hot deformation austenite in 55SiCr steel was measured on Gleeble-1500 thermal simulation machine, the microstructure and hardness of transformation products under different cooling velocities were observed. The microstructure transformation regularity with being cooled continuously were emphatically researched at the cooling rate form 0.1°C/s to 15 °C/s. The results can provide a instruction for producing 55SiCr steel.

Method for Estimating the Critical Cooling Rate for Glass Formation from Isothermal TTT Data

2007 ◽  
Vol 336-338 ◽  
pp. 1874-1877 ◽  
Author(s):  
Dong Mei Zhu ◽  
Wan Cheng Zhou ◽  
Chandra S. Ray ◽  
Delbert E. Day
Keyword(s):  
Cooling Rate ◽  
Glass Formation ◽  
Lithium Disilicate ◽  
Nucleating Agent ◽  
Cooling Rates ◽  
Continuous Cooling Transformation ◽  
Critical Cooling Rate ◽  
Continuous Cooling ◽  
Transformation Curve ◽  
Continuous Cooling Transformation Curve

A method is proposed for estimating the critical cooling rate for glass formation and continuous cooling transformation curve (CCT) from isothermal TTT data. The critical cooling rates and CCT curves for a group of lithium disilicate glasses containing different amount of Pt as nucleating agent estimated through this method are compared with the experimentally measured values and it shows this method can give a reasonable estimation.

scholarly journals Study on High-Temperature Mechanical Properties of Fe–Mn–C–Al TWIP/TRIP Steel

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 821
Author(s):  
Guangkai Yang ◽  
Changling Zhuang ◽  
Changrong Li ◽  
Fangjie Lan ◽  
Hanjie Yao
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Low Temperature ◽  
Tensile Fracture ◽  
Temperature Range ◽  
High Temperature Mechanical Properties ◽  
Ductility Trough ◽  
Different Temperatures ◽  
Reduction Of Area ◽  
High Temperature Tensile

In this study, high-temperature tensile tests were carried out on a Gleeble-3500 thermal simulator under a strain rate of ε = 1 × 10−3 s−1 in the temperature range of 600–1310 °C. The hot deformation process of Fe–15.3Mn–0.58C–2.3Al TWIP/TRIP at different temperatures was studied. In the whole tested temperature range, the reduction of area ranged from 47.3 to 89.4% and reached the maximum value of 89.4% at 1275 °C. Assuming that 60% reduction of area is relative ductility trough, the high-temperature ductility trough was from 1275 °C to the melting point temperature, the medium-temperature ductility trough was 1000–1250 °C, and the low-temperature ductility trough was around 600 °C. The phase transformation process of the steel was analyzed by Thermo-Calc thermodynamics software. It was found that ferrite transformation occurred at 646 °C, and the austenite was softened by a small amount of ferrite, resulting in the reduction of thermoplastic and formation of the low-temperature ductility trough. However, the small difference in thermoplasticity in the low-temperature ductility trough was attributed to the small amount of ferrite and the low transformation temperature of ferrite. The tensile fracture at different temperatures was characterized by means of optical microscopy and scanning electron microscopy. It was found that there were Al2O3, AlN, MnO, and MnS(Se) impurities in the fracture. The abnormal points of thermoplasticity showed that the inclusions had a significant effect on the high-temperature mechanical properties. The results of EBSD local orientation difference analysis showed that the temperature range with good plasticity was around 1275 °C. Under large deformation extent, the phase difference in the internal position of the grain was larger than that in the grain boundary. The defect density in the grain was large, and the high dislocation density was the main deformation mechanism in the high-temperature tensile process.

Influence on the Microstructure of Pinion Steel with Different Cooling Rates after Normalizing

2014 ◽  
Vol 513-517 ◽  
pp. 12-15
Author(s):  
Zhi Jun He ◽  
Jing Li ◽  
Jin Xin Liu
Keyword(s):  
Heat Treatment ◽  
Cooling Rate ◽  
Cooling Rates ◽  
Continuous Cooling Transformation ◽  
Continuous Cooling ◽  
Transformation Curve ◽  
Steel Heat ◽  
Continuous Cooling Transformation Curve

According to continuous cooling transformation curve of pinion steel, heat treatment simulation tests of 8 series were developed. The results show that the microstructure of pinion steel depends on the cooling rate after normalizing. Furnace cooling according to 30°C/h after normalizing can get the typical F+P organizations; Converter cooling after normalizing mixed with some bainite organizations; Furnace cooling with the break after normalizing can get clear stripped bainite organizations.

TEM Studies of Grain Boundary Films in Si3N4 Ceramics

1991 ◽  
Vol 49 ◽  
pp. 930-931
Author(s):  
H.-J. Kleebe ◽  
J.S. Vetrano ◽  
J. Bruley ◽  
M. Rühle
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Silicon Nitride ◽  
Hot Isostatic Pressing ◽  
Amorphous Film ◽  
Liquid Phase Sintering ◽  
Second Phase ◽  
High Temperature Mechanical Properties ◽  
Triple Points ◽  
Boundary Films

It is expected that silicon nitride based ceramics will be used as high-temperature structural components. Though much progress has been made in both processing techniques and microstructural control, the mechanical properties required have not yet been achieved. It is thought that the high-temperature mechanical properties of Si3N4 are limited largely by the secondary glassy phases present at triple points. These are due to various oxide additives used to promote liquid-phase sintering. Therefore, many attempts have been performed to crystallize these second phase glassy pockets in order to improve high temperature properties. In addition to the glassy or crystallized second phases at triple points a thin amorphous film exists at two-grain junctions. This thin film is found even in silicon nitride formed by hot isostatic pressing (HIPing) without additives. It has been proposed by Clarke that an amorphous film can exist at two-grain junctions with an equilibrium thickness.

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