Characterization of Hot Deformation of Nb-V-Ti Microalloyed Steel Using Processing Map

2009 ◽  
Vol 79-82 ◽  
pp. 1439-1442
Author(s):  
Song Xiang ◽  
Guo Quan Liu
Keyword(s):  
Strain Rate ◽  
Power Dissipation ◽  
Hot Deformation ◽  
Microalloyed Steel ◽  
Rate Sensitivity ◽  
Strain Rate Range ◽  
Processing Maps ◽  
Peak Efficiency ◽  
Power Dissipation Efficiency ◽  
Working Parameters

The hot deformation behavior of Nb-V-Ti microalloyed steel in the temperature range of 850°C～1100°C and the strain rate range of 0.001s-1～30s-1 was investigated by establishing the processing maps. The strain rate sensitivity (m), power dissipation efficiency (η) and instability parameter were calculated based on the experimental compression data and are plotted in the temperature–strain rate plane to obtain power dissipation and instability maps. The processing maps exhibit that the deformation at 1000°C and 2s-1 is one peak efficiency of power dissipation of 21%, the deformation at 1050°C and 0.01~0.001 s-1 is another peak efficiency of power dissipation of 45%. The optical microstructure observations show that they represent two dynamic recrystallization domains. Based on the above processing maps, the hot working parameters were optimized.

Hot Workability Analysis of Extruded Mg-Zn-Mn-Y Magnesium Alloys with Different Phases

2012 ◽  
Vol 184-185 ◽  
pp. 1010-1016
Author(s):  
Wei Wei He ◽  
Kun Zhang ◽  
Min Huang ◽  
Sheng Long Dai
Keyword(s):  
Strain Rate ◽  
Magnesium Alloys ◽  
Power Dissipation ◽  
Rate Sensitivity ◽  
Processing Maps ◽  
Hot Workability ◽  
Compression Tests ◽  
Secondary Phases ◽  
Forming Process ◽  
Power Dissipation Efficiency

Workability, an important parameter in magnesium alloys forming process, can be evaluated by means of processing maps on the basis of dynamic materials model, constructed from experimentally generated flow stress variation with respect to strain, strain rate and temperature. To obtain the processing maps of extruded Mg-Zn-Mn-Y magnesium alloy with different secondary phases (I-phase and W-phase), hot compression tests were performed over a range of temperatures 523–673 K and strain rates 0.001~10s-1. The response of strain-rate sensitivity (m-value), power dissipation efficiency (ζ-value) and instability parameter (n-value) to temperature and strain rate were evaluated. By the superimposition of the power dissipation and the instability maps, the dynamic recrystallization (DRX) and instability zones were identified and validated through micrographs. The observations were performed in order to describe the behavior of the material under hot forming operation in terms of material damage and micro-structural modification.

Characterization of Hot Deformation Behavior of Zr-4 Alloy in Material Application Area

2012 ◽  
Vol 578 ◽  
pp. 202-205
Author(s):  
Guo Qing Lin
Keyword(s):  
Strain Rate ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Flow Behavior ◽  
Strain Rate Range ◽  
Processing Maps ◽  
Peak Efficiency ◽  
Hot Deformation Behavior ◽  
Rate Range ◽  
Temperature Range

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.

Development of Processing Maps for DC Cast Modified and Unmodified Hypereutectic Al-Si Alloys

2011 ◽  
Vol 213 ◽  
pp. 116-120
Author(s):  
Ke Zhun He ◽  
Fu Xiao Yu ◽  
Da Zhi Zhao ◽  
Liang Zuo
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
Power Dissipation ◽  
Hot Deformation ◽  
High Strain ◽  
Strain Rate Range ◽  
Instability Region ◽  
Processing Maps ◽  
Unmodified Alloy ◽  
Primary Si

The hot deformation behavior of DC cast phosphorous modified and unmodified hypereutectic Al-Si alloys was studied in the temperature range of 400-500 °C and strain rate range of 0.001-1 s-1. Processing maps were developed to evaluate the efficiency of the hot deformation and to identify the instability region. The results show that the peak stresses of the unmodified alloy are higher than that of the modified alloy at the strain rate of 1 s-1 and temperatures of 400 and 440 °C. The maximum power dissipation efficiencies for both the alloys are in the region of T=480-500 °C and =0.01-0.1 s-1. The flow instabilities for both the alloys occur in regions of high strain rate about 1 s-1 and temperature about 400 and 500 °C. The instability region area of the unmodified alloy is larger than that of the modified alloy. In addition, the primary Si cracking frequencies of the unmodified alloy are higher than that of the modified alloy when compared at the same deformation rate and temperature. The coarser primary Si particles of the unmodified alloy cause higher stress concentration around them when deformed at low temperature and high strain rate.

Plastic Deformation at High Temperature and Processing Map of AZ61 Magnesium Alloy

2014 ◽  
Vol 926-930 ◽  
pp. 182-185
Author(s):  
Quan Li ◽  
Wen Jun Liu ◽  
Ren Ju Cheng ◽  
Shan Jiang ◽  
Su Qin Luo ◽  
...  
Keyword(s):  
Strain Rate ◽  
Power Dissipation ◽  
Deformation Behavior ◽  
Processing Map ◽  
Rate Sensitivity ◽  
Strain Rate Range ◽  
Processing Maps ◽  
Rate Range ◽  
Optimum Parameters ◽  
Az61 Magnesium Alloy

The deformation behavior of as-cast AZ61 alloy in the temperature range 300-450°C and in the strain rate range 0.01~5 s−1 has been studied using processing maps. For obtaining the processing map, the variation of the efficiency of power dissipation given by [2m/(m+1)] where ‘m’ is the strain rate sensitivity, is plotted as a function of temperature and strain rate. The map exhibited a domain of dynamic recrystallization (DRX) occurring at 425 °C and 0.1 s−1 which are the optimum parameters for hot working of the alloy.

Study of Hot Deformation Characteristics of an As-Cast Ti-22Al-25Nb Alloy

2007 ◽  
Vol 546-549 ◽  
pp. 1461-1466 ◽  
Author(s):  
Xiao Bo Liang ◽  
Shi Qiong Li ◽  
Jian Wei Zhang ◽  
Yun Jun Cheng
Keyword(s):  
Steady State ◽  
Strain Rate ◽  
Power Dissipation ◽  
Hot Deformation ◽  
Strain Rate Range ◽  
Deformation Characteristics ◽  
Rate Range ◽  
Temperature Range ◽  
Power Dissipation Efficiency ◽  
B2 Phase

The hot deformation characteristics of an as-cast Ti-22Al-25Nb alloy has been studied in the temperature range of 1323-1523K and the strain rate range of 0.001-10s-1, using hot compression tests. The experimental results indicated that discontinuous yielding occurs during the hot deformation performed at the strain rate of 10s-1, while the flow curves are of a steady-state type at lower strain rate range. Activation energy was obtained by analyzing the steady-state flow stress with a standard constitutive equation. They are 260-282kJ/mol in the temperature range of 1473-1523K, and 145-155kJ/mol in 1323-1423K. The processing map developed using the principles of dynamic material modeling exhibits three domains for the present alloy: 1) a domain of dynamic recrystallization of B2 phase in the temperature range of 1373-1423K at the strain rate range of 0.01-0.001s-1, with the power dissipation efficiency of about 35-50%, 2) a domain of dynamic recovery of B2 phase in the temperature range of 1473-1523K at the strain rate less than 0.01s-1, with the power dissipation efficiency of about 20-30%, 3) a domain of flow instability in the form of adiabatic shear band in the temperature range of 1323-1373K at the strain rate larger than 1s-1.

Hot Deformation Behavior and Processing Maps of Cr-Ni-Mn-N Austenitic Stainless Steel

2011 ◽  
Vol 704-705 ◽  
pp. 210-215
Author(s):  
Er Bao ◽  
Ming Jia Wang ◽  
Zi Xi Wang ◽  
Huan He
Keyword(s):  
Stainless Steel ◽  
Strain Rate ◽  
Power Dissipation ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Processing Maps ◽  
Peak Efficiency ◽  
Hot Deformation Behavior ◽  
Complete Recrystallization ◽  
Gleeble 3500

The hot deformation behavior of a Cr-Ni-Mn-N series stainless steel was studied at temperatures from 850°C to 1175°C with the strain rate ranging from 0.01 s−1 to 10 s−1 using a Gleeble-3500 simulator. The constitutive equation and processing maps were compiled based on a hot compression test to strain of 0.9. The deformation microstructures were observed systematically by optical microscopy. Results show that the efficiency of power dissipation gradually increases with rising temperature and decreasing strain rate. The maps at strains of 0.5 and 0.9 show two distinct domains with one having the peak efficiency of about 28–35% at 1150°C–1175°C and 1–10 s−1 and the other having the peak efficiency of about 33–45% at 1050°C–1150°C and 0.01–0.5 s−1, while complete recrystallization is evident.

scholarly journals Hot Deformation Behaviour and Processing Map of Cast Alloy 825

2021 ◽  
Author(s):  
Munir Al-Saadi ◽  
Christopher Hulme-Smith ◽  
Fredrik Sandberg ◽  
Pär G. Jönsson
Keyword(s):  
Strain Rate ◽  
Vickers Hardness ◽  
Power Dissipation ◽  
Hot Deformation ◽  
Processing Map ◽  
Cast Alloy ◽  
True Strain ◽  
Processing Conditions ◽  
Temperature Range ◽  
Power Dissipation Efficiency

AbstractAlloy 825 is a nickel-based alloy that is commonly used in applications where both high strength and corrosion resistance are required, such as tanks in the chemical, food and petrochemical industries and oil and gas pipelines. Components made from Alloy 825 are often manufactured using hot deformation. However, there is no systematic study to optimise the processing conditions reported in literature. In this study, a processing map for as-cast Alloy 825 is established to maximise the power dissipation efficiency of hot deformation in the temperature range of 950 to 1250 °C at an interval of 50 °C and strain rate range of $$0.01\, {\text{s}}^{ - 1}$$ 0.01 s - 1 to $$10.0\, {\text{s}}^{ - 1}$$ 10.0 s - 1 to a true strain of $$0.7$$ 0.7 using a Gleeble-3500 thermomechanical simulator. The processing conditions are also correlated to the Vickers hardness of the final material, which is also characterised using optical microscopy and scanning electron microscopy, including electron backscattered diffraction. The true stress-true strain curves exhibit peak stresses followed by softening due to occurrence of dynamic recrystallization. The activation energy for plastic flow in the temperature range tested is approximately $$450\,{\text{ kJ mol}}^{ - 1}$$ 450 kJ mol - 1 , and the value of the stress exponent in the (hyperbolic sine-based) constitutive equation, $$n = 5.0$$ n = 5.0 , suggests that the rate-limiting mechanism of deformation is dislocation climb. Increasing deformation temperature led to a lower Vickers hardness in the deformed material, due to increased dynamic recrystallization. Raising the strain rate led to an increase in Vickers hardness in the deformed material due to increased work hardening. The maximum power dissipation efficiency is over $$35\%$$ 35 % , obtained for deformation in the temperature range 1100-1250 °C and a strain rate of $$0.01\, {\text{s}}^{ - 1}$$ 0.01 s - 1 -$$0.1\, {\text{s}}^{ - 1}$$ 0.1 s - 1 . These are the optimum conditions for hot working.

scholarly journals Effect of Nitrogen Content on Hot Deformation Behavior and Grain Growth in Nuclear Grade 316LN Stainless Steel

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Ming-wei Guo ◽  
Zhen-hua Wang ◽  
Ze-an Zhou ◽  
Shu-hua Sun ◽  
Wan-tang Fu
Keyword(s):  
Stainless Steel ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Grain Growth ◽  
Strain Rate Sensitivity ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Rate Sensitivity ◽  
Processing Maps ◽  
Hot Deformation Behavior

316LN stainless steel with 0.08%N (08N) and 0.17%N (17N) was compressed at 1073–1473 K and 0.001–10 s−1. The hot deformation behavior was investigated using stress-strain curve analysis, processing maps, and so forth. The microstructure was analyzed through electron backscatter diffraction analysis. Under most conditions, the deformation resistance of 17N was higher than that of 08N. This difference became more pronounced at lower temperatures. The strain rate sensitivity increased with increasing temperature for types of steel. In addition, the higher the N content, the higher the strain rate sensitivity. Hot deformation activation energy increased from 487 kJ/mol to 549 kJ/mol as N concentration was increased from 0.08% to 0.17%. The critical strain for initiation of dynamic recrystallization was lowered with increasing N content. In the processing maps, both power dissipation ratio and unstable region increased with increasing N concentration. In terms of microstructure evolution, N promoted dynamic recrystallization kinetic and decreased dynamic recrystallization grain size. The grain growth rate was lower in 17N than in 08N during heat treatment. Finally, it was found that N favored twin boundary formation.

Study on Hot Processing Maps and Flow Instability of 1235 Al Alloy Treated by Different Methods of Purification

2011 ◽  
Vol 399-401 ◽  
pp. 1870-1877
Author(s):  
Gao Sheng Fu ◽  
Wen Duan Yan ◽  
Hong Ling Chen ◽  
Gui Qing Chen ◽  
Chao Zeng Cheng
Keyword(s):  
Strain Rate ◽  
Power Dissipation ◽  
Flow Instability ◽  
Al Alloy ◽  
Processing Maps ◽  
Hot Workability ◽  
Optimum Processing ◽  
Lower Strain ◽  
Power Dissipation Efficiency ◽  
Higher Temperature

Based on the theory of processing map proposed by PRASAD, the power dissipation maps, the hot deformation instability maps and the hot processing maps of 1235 Al alloys treated by different methods of purification were built, and the effects of purification and deformation conditions at elevated-temperature on hot workability of 1235 Al alloy were analyzed. At the same time the optimum processing region and flow instability region were determined. The results show that the hot processing map of 1235 Al alloy has two instability zones in the temperature range of 300-500°C and in the strain rate ranging from 0.01s-1to 10.0s-1up to a true strain of 0.7, that is, one zone lying in the range of lower temperature and higher strain rate, the other zone in the range of higher temperature and mid strain rate. The purification effect has significant impact on hot workability of the alloy. It is found that the optimum processing region of 1235 Al alloy treated by high-efficient purification treatment is present in the range of higher temperature and lower strain rate zone, and its power dissipation efficiency is about 46%; while the optimum processing region of 1235 Al alloys treated by conventional refining treatment is present in the range of mid-temperature and lower strain rate zone or in the range of higher temperature and strain rate zone, and its power dissipation efficiency is about 23-29%. The results of observation of the deformation microstructure of 1235 Al alloy are in accordance with that of the hot processing maps of the alloy, thus showing that the calculation results of the hot processing maps are reliable.

Deformation Heating and Its Effect on the Processing Maps of Ti-15-3 Titanium Alloy

2013 ◽  
Vol 712-715 ◽  
pp. 58-64
Author(s):  
Jing Qi Zhang ◽  
Hong Shuang Di ◽  
Xiao Yu Wang
Keyword(s):  
Titanium Alloy ◽  
Strain Rate ◽  
Rate Sensitivity ◽  
Strain Rate Range ◽  
Processing Maps ◽  
Compression Tests ◽  
Temperature Range ◽  
Deformation Heating ◽  
Instability Criteria ◽  
Flow Stress Data

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.

Sign in / Sign up

Export Citation Format

Share Document