The Constitutive Relationship and Processing Map of Hot Deformation in A100 steel

2016 ◽  
Vol 35 (4) ◽  
pp. 399-405 ◽  
Author(s):  
Yongkang Liu ◽  
Zongmei Yin ◽  
Junting Luo ◽  
Zhang Chunxiang ◽  
Yanshu Zhang

AbstractIsothermal compression tests were conducted on A100 steel using a Gleeble 1500 thermal simulator at a temperature range of 900–1,200°C and strain rate range of 0.001–3 s−1. Results show that the A100 steel has higher strength than the Aermet 100 steel at high temperatures. Constant values, such as A, α, and n, and activate energy Q were obtained through the regression processing of the stress–strain data curves under different strains. A set of constitutive equations for A100 steel was proposed by using an Arrhenius-type equation. The optimum processing craft ranges for A100 steel based on the analysis of the hot working diagram and deformation mechanism are as follows: temperature range of 1,000–1,100°C and strain rate range of 0.01–0.1 s−1. The average grain size within this working range is 7–22.5 μm.

2012 ◽  
Vol 490-495 ◽  
pp. 3423-3426 ◽  
Author(s):  
Xin Zhao ◽  
Hong Zhao ◽  
Rui Zhang

The hot deformation characteristics of TC18 titanium alloy were studied in the temperature range 750-850°C and strain rate range 0.001-1 s-1 by using hot compression tests. Processing maps for hot working are developed on the basis of the variations of efficiency of power dissipation with temperature and strain rate. The results reveal that the flow stress of TC18 is sensitive to strain rate. Processing map at stain of 0.6 reveals two domains: one is centered at 750°C and 0.001s-1; another is centered at 850°C and 0.001s-1. The maximum efficiency is more than 60%. According to the maps, the zone with the temperature range of 750-850°C and strain rate range of 0.01-0.001s-1 may be suitable for hot working


Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2282 ◽  
Author(s):  
Zhimin Zhang ◽  
Zhaoming Yan ◽  
Yue Du ◽  
Guanshi Zhang ◽  
Jiaxuan Zhu ◽  
...  

Mg-Gd-Y-Zn-Zr Mg alloys show excellent performance in high-end manufacturing due to its strength, hardness and corrosion resistance. However, the hot deformation and dynamic recrystallization (DRX) behaviors of Mg-13.5Gd-3.2Y-2.3Zn-0.5Zr were not studied. For this article, hot compression behavior of homogenized high rare-earth (RE) content Mg-13.5Gd-3.2Y-2.3Zn-0.5Zr (wt%) alloy was investigated by using the Gleeble-3500D thermo-simulation test machine under the temperature of 350–500 °C and the strain rate of 0.001–1 s−1. It was found that the high flow stress corresponded to the low temperature and high strain rate, which showed DRX steady state curve during the hot compression. The hot deformation average activation was 263.17 kJ/mol, which was obtained by the analysis of the hyperbolic constitutive equation and the Zener-Hollomon parameter. From observation of the microstructure, it was found that kink deformation of long period stacking ordered (LPSO) phase was one of the important coordination mechanisms of hot deformation at low temperature. The processing map with the strain of 0.5 was established under the basis of dynamic material model (DMM); it described two high power dissipation domains: one appearing in the temperature range of 370–440 °C and the strain rate range of 0.001–0.006 s−1, the other appearing in the temperature range of 465–500 °C and strain rate range of 0.001–0.05 s−1, in which dynamic recrystallization (DRX) mainly ocurred. The highest degree of DRX was 18% from the observation of the metallographic.


Author(s):  
YL Wang ◽  
Y Li ◽  
H Zhang ◽  
JL Yang ◽  
XD Ma ◽  
...  

Quasi-static hot deformation behavior of a novel third-generation Ni-based powder metallurgy superalloy A3 was investigated by hot compression tests and microscopy. The activation energy for hot working of the experimental alloy was about 867 kJ/mol. An instability domain existed in the processing map when the strain was 0.2, implying a plastic instability at the temperature range of 1080–1100°C and the strain rate range of 0.016–0.1 s−1. The power dissipation efficiency in processing maps indicated that optimum parameters for large deformation could be controlled at the temperature range of 1000–1030°C and the strain rate range of 0.001–0.01 s−1. It provided a reliable suggestion for hot processing during the manufacturing of such superalloy.


2014 ◽  
Vol 915-916 ◽  
pp. 588-592
Author(s):  
Gang Chen ◽  
Wei Chen ◽  
Guo Wei Zhang ◽  
Jing Zhai ◽  
Li Ma

Compression tests of Mg-4Al-3Ca-1.5Zn-1Nd-0.2Mn Magnesium alloy as-extruded had been performed in the compression temperature range from 200°C to 350°C and the strain rate range from 0.001 s1to 1 s1and the flow stress data obtained from the tests were used to develop the power dissipation map, instability map and processing map. The optimum parameters for hot working of the alloy had been determined. According to the processing maps, the most optimal temperature range is 280°C to 350°C and most optimal strain rate range is 0.001 S-1to 1 S-1.


2012 ◽  
Vol 538-541 ◽  
pp. 1257-1261
Author(s):  
Sheng Li Guo ◽  
Peng Du ◽  
Xiao Ping Wu ◽  
De Fu Li

The hot deformation behavior of Zn91.8-Cu8-Cr0.2 (in wt.%) was investigated by means of hot compression tests in the temperature range of 230-380 °C and strain rate range of 0.01 - 10 s-1. The constitutive equation and processing maps were developed. The influence of strain on the flow stress was studied by considering the effect of the strain on material constants. The stress-strain curves obtained by the constitutive equation are in good agreement with experimental results. The proposed constitutive equations can be used for the analysis problem of hot forming processes. The processing maps have exhibited a domain, which is optimum processing window for hot working, in the temperature range of 310 - 380 °C and strain rate range of 0.01-1 s-1 corresponding to the higher efficiency of power dissipation. The large regime of flow instability is observed at high strain rate. The instability regime should be avoided during hot deformation processing.


2004 ◽  
Vol 449-452 ◽  
pp. 577-580
Author(s):  
Young Sang Na ◽  
Young Mok Rhyim ◽  
J.Y. Lee ◽  
Jae Ho Lee

In order to quantitatively analyze the critical strain for the initiation of dynamic recrystallization in Ni-Fe-based Alloy 718, a series of uniaxial compression tests was conducted in the temperature range 927°C - 1066°C and the strain rate range 5 x 10-4s-1- 5 s-1with varying initial grain size. The critical strains were graphically determined based on one parameter approach and microscopically confirmed. The effect of γ'' (matrix-hardening phase) and δ (grain boundary phase)on the critical strain was simply discussed. The constitutive model for the critical strain of Alloy 718 was constructed using the experimental data obtained from the higher strain rate and the temperature range between 940°C and 1040°C.


2013 ◽  
Vol 712-715 ◽  
pp. 58-64
Author(s):  
Jing Qi Zhang ◽  
Hong Shuang Di ◽  
Xiao Yu Wang

In the present study, deformation heating generated by plastic deformation and its effect on the processing maps of Ti-15-3 titanium alloy were investigated. For this purpose, hot compression tests were performed on a Gleeble-3800 thermo-mechanical simulator in the temperature range of 850-1150 °C and strain rate range of 0.001-10 s1. The temperature rise due to deformation heating was calculated and the as-measured flow curves were corrected for deformation heating. Using the as-measured and corrected flow stress data, the processing maps for Ti-15-3 titanium alloy at a strain of 0.5 were developed on the basis Murty‘s and Babu’s instability criteria. The results show that both the instability maps based the two instability criteria are essentially similar and are characterized by an unstable region occurring at strain rates higher than 0.1 s1for almost the entire temperature range tested. The unstable regions are overestimated from the as-measured data due to the effect of deformation heating, indicating a better workability after correcting the effect of deformation heating. This is further conformed by the analysis based on strain rate sensitivity.


2012 ◽  
Vol 578 ◽  
pp. 202-205
Author(s):  
Guo Qing Lin

The hot deformation behavior of Zr-4 alloy was studied in the temperature range 650-900°C and strain rate range 0.005-50s-1 using processing maps. The processing maps revealed three domains: the first occurs in the temperature range 780-820°C and strain rate range 0.005-0.05s-1, and has a peak efficiency of 45% at 790°C and 0.005s-1; the mechanism is the dynamic recrystallization. The second occurs in the temperature range greater than 900°C and strain rate range 0.05-0.8s-1, and has a peak efficiency of 40% at 900°C and 0.5s-1, which are the domains of dynamic recovery. In addition, the instability zones of flow behavior can also be recognized by the maps in the temperature range 650-780°C and strain rate range 0.01-0.1s-1, which should be strictly avoided in the processing of the material. Zr-4 alloy is the material for pressure tube applications in nuclear reactors and has better strength and a lower rate of hydrogen uptake compared to other materials under similar service conditions.


2011 ◽  
Vol 189-193 ◽  
pp. 2847-2850
Author(s):  
Ming Yang ◽  
Yong Shun Yang ◽  
Dong Dong Yang

Using the compression tests on a Gleeble-1500 thermo-mechanical simulator to study the dynamic recrystallization behaviours of AZ80 magnesium alloy in the temperature range of 593-683K and strain rate range of 0.01-10s-1. By the analysis of the dynamic recrystallization kinetics, the Avrami exponent (m) and the constant (k) have been determined, and they aren’t constant and depend on the dimensionless parameter(Z/A).


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