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 Microstructure Evolution and Hot Deformation Behavior of a CuNiSn Alloy

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 451
Author(s):  
Yexin Jiang ◽  
Xu Wang ◽  
Zhou Li ◽  
Zhu Xiao ◽  
Xiaofei Sheng ◽  
...  
Keyword(s):  
Flow Stress ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Power Dissipation ◽  
Hot Deformation ◽  
Deformation Behavior ◽  
Flow Instability ◽  
True Strain ◽  
Hot Deformation Behavior ◽  
Power Dissipation Efficiency

The hot deformation behavior of Cu-20.0Ni-5.0Sn-0.25Zn-0.22Mn was investigated using a Gleeble-3500 thermal simulator with a temperature range from 720 °C to 880 °C and a strain rate range from 0.001 s−1 to 1 s−1. The results show that the flow stress increased with the increase of the strain rate and the decrease of the temperature. The constitutive equation of the alloy was established based on the peak flow stress. Figures of the power dissipation efficiency and flow instability with the variable of the true strain from 0.2 to 0.8 displayed the dynamic change of power dissipation efficiency and the instability area. The domain of 730–770 °C and 0.001–0.01 s−1 possessed a power dissipation efficiency over 40% throughout the whole deformation. The flow instability always appeared at a high strain rate from 0.1 s−1 to 1 s−1 during the whole deformation process. The nucleation site of the dynamic recrystallization generally appeared along the grain boundaries, indicating the discontinuous dynamic recrystallization mechanism. The appropriate conditions for deformation with a true strain of 0.9 is in a safe domain (820–860 °C with a strain rate of 0.001–0.01 s−1). There were four kinds of variation tendencies of the power dissipation efficiency with the increase of the true strain under various conditions, suggesting a changing situation for the main softening mechanisms.

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 working of SP-700 titanium alloy with lamellar α + β starting structure using a processing map

2020 ◽  
Vol 111 (4) ◽  
pp. 297-306
Author(s):  
Amir Hosein Sheikhali ◽  
Maryam Morakkabati
Keyword(s):  
Titanium Alloy ◽  
Strain Rate ◽  
Hot Deformation ◽  
Processing Map ◽  
Microstructural Analysis ◽  
Shear Bands ◽  
Alpha Phase ◽  
Strain Rates ◽  
Compression Tests ◽  
Temperature Range

Abstract In this study, hot deformation behavior of SP-700 titanium alloy was investigated by hot compression tests in the temperature range of 700-9508C and at strain rates of 0.001, 0.1, and 1 s-1. Final mechanical properties of the alloy (hot compressed at different strain rates and temperatures) were investigated using a shear punch testing method at room temperature. The flow curves of the alloy indicated that the yield point phenomenon occurs in the temperature range of 800- 9508C and strain rates of 0.1 and 1 s-1. The microstructural analysis showed that dynamic globularization of the lamellar α phase starts at 7008C and completes at 8008C. The alpha phase was completely eliminated from b matrix due to deformation- induced transformation at 8508C. The microstructure of specimens compressed at 8508C and strain rates of 0.001 and 0.1 s-1showed the serration of beta grain boundaries, whereas partial dynamic recrystallization caused a necklace structure by increasing strain rate up to 1 s-1. The specimen deformed at 7008C and strain rate of 1 s-1was located in the instability region and localized shear bands formed due to the low thermal conductivity of the alloy. The processing map of the alloy exhibited a peak efficiency domain of 54% in the temperature range of 780-8108C and strain rates of 0.001- 0.008 s-1. The hot deformation activation energy of the alloy in the α/β region (305.5 kJ mol-1) was higher than that in the single-phase β region (165.2 kJ mol-1) due to the dynamic globularization of the lamellar a phase.

scholarly journals Constitutive Equation and Hot Processing Map of a Nitrogen-Bearing Martensitic Stainless Steel

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1502
Author(s):  
Xiao Li ◽  
Lifeng Hou ◽  
Yinghui Wei ◽  
Zhengyan Wei
Keyword(s):  
Stainless Steel ◽  
Constitutive Equation ◽  
Strain Rate ◽  
Hot Deformation ◽  
Processing Map ◽  
Martensitic Stainless Steel ◽  
True Strain ◽  
True Stress ◽  
Hot Working ◽  
Compression Tests

The hot deformation behavior of a nitrogen-bearing martensitic stainless steel was researched by the isothermal compression test in the temperature range of 950–1150 °C and strain rate range of 0.01–10 s−1 with a Gleeble-3800 thermal-mechanical simulating tester. A strain compensated sine-hyperbolic Arrhenius-type constitutive equation was developed to describe the relationship between true stress and deformation parameters such as temperature, strain rate and true strain. The hot deformation activation energy is calculated to be from 407 to 487 KJ mol−1. It is validated by the standard statistical parameters that the established constitutive equation can accurately predict the true stress. The processing maps at different true strains were constructed based on the dynamic material model (DMM) and the true stress data obtained from the hot compression tests. Two unstable regions which should be avoided during hot working were observed from the processing map. In addition, the optimum hot working parameters are located in the domain of 1000–1150 °C/0.1–1 s−1 with the peak power dissipation efficiency of 39.9%, in which complete dynamic recrystallization (DRX) occurs.

Investigation of Hot Deformation Characteristics of AISI 4340 Steel Using Processing Map

2013 ◽  
Vol 683 ◽  
pp. 301-306 ◽  
Author(s):  
Apichat Sanrutsadakorn ◽  
Vitoon Uthaisangsuk ◽  
Surasak Suranuntchai ◽  
Borpit Thossatheppitak
Keyword(s):  
Strain Rate ◽  
Power Dissipation ◽  
Hot Deformation ◽  
Processing Map ◽  
Hot Working ◽  
Instability Criterion ◽  
Peak Efficiency ◽  
Aisi 4340 Steel ◽  
4340 Steel ◽  
Aisi 4340

Uniaxial compression tests at various temperatures from 850°C to 1200°C and strain rates between 0.01 s-1 and 10 s-1 were carried out in order to determine hot working characteristic of the AISI 4340 steel. The plastic stress-strain responses at high temperatures of the steel were provided. Constitutive relationship between the flow stresses and the Zener–Hollomon parameters was primarily established by means of a hyperbolic sine function for the entire range of the investigated conditions. Afterwards, the power dissipation map and instability map were developed on the basis of the Dynamic Materials Model (DMM). The variation of efficiency of the power dissipation calculated as a function of strain rate sensitivity represented material behaviors according to the microstructure evolution. The peak efficiency indicated an optimum processing window for hot working. In this study, processing map was obtained by a superimposition of the power dissipation and the instability criterion. The domains of temperature and strain rate, in which material flow stability occurred, were determined. For the AISI 4340 steel, the processing maps exhibited a distinct domain with its peak efficiency at about 1050-1200°C and 0.01-0.1 s-1, in which the peak efficiencies of about 40-50% were shown for different strains. In combination with microstructure observations after hot deformation, dynamic recrystallization zone could be identified in the processing map at a certain strain.

Hot Deformation Behavior and Processing Map of a Nickel-Base Superalloy GH4169

2013 ◽  
Vol 834-836 ◽  
pp. 432-436 ◽  
Author(s):  
Fu Wei Kang ◽  
Xue Min Zhang ◽  
Jian Fei Sun ◽  
Jun Ling Zhao
Keyword(s):  
Strain Rate ◽  
Power Dissipation ◽  
Hot Deformation ◽  
True Strain ◽  
Stability Domain ◽  
Nickel Base Superalloy ◽  
Peak Efficiency ◽  
True Strain Rate ◽  
Nickel Base ◽  
Base Superalloy

The hot deformation behaviors of the nickel-base superalloy GH4169 have been studied by isothermal constant true strain rate compression testing at 950°C-1150°C, 0.01s-1-10s-1and the height reduction 50%. The processing maps of GH4169 alloy have been constructed at different strains on the basis of testing data using a dynamic materials modeling. The maps exhibited two domains: the first at 950°C - 1100°C and strain rate higher than 0.1s-1, with a peak efficiency of power dissipation of 0.1, and the second at 950°C-1100°C and strain rate lower than 1s-1, with a peak efficiency of power dissipation of 0.4 and the strain rate of 0.01s-1. On the basis of microstructure observations, the first exhibits adiabatic shear bands, which called instability domain, the second represents fine recrystallized grain structures, which called stability domain. The optimal hot-working parameters are at 1050°C, 0.01s-1.

scholarly journals Hot Deformation Characteristics of 18Cr-5Ni-4Cu-N Stainless Steel Using Constitutive Equation and Processing Map

Metals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 82
Author(s):  
Xiao-yang Fu ◽  
Pu-cun Bai ◽  
Ji-chun Yang
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Stainless Steel ◽  
Constitutive Equation ◽  
Grain Boundary ◽  
Strain Rate ◽  
Hot Deformation ◽  
Processing Map ◽  
Temperature Range ◽  
Calculation Results

The hot deformation of 18Cr-5Ni-4Cu nitrogen-alloyed austenitic stainless steel was tested with a Gleeble-1500D simulator in the temperature range of 1273–1473 K and in the strain rate range of 0.01–10 s−1. The Zener-Hollomon parameter method was used to construct a constitutive equation for high-temperature plastic deformation. The energy dissipation diagram of the material was calculated based on dynamic material modelling (DMM). The microstructural variations were characterized via X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) with energy dispersive spectroscopy (EDS) and transmission electron microscopy (TEM). The thermodynamic calculation results showed that the addition of nitrogen to 18Cr-5Ni-4Cu steel promoted the formation of Cr2N and gas phases and expanded the austenite phase region; these results were consistent with the XRD test results of the solid solution sample. The hot deformation activation energy after nitrogen addition was 556.46 kJ∙mol−1. The processing map predicted that the optimum hot working regimes were in the temperature range of 1416–1461 K, where ln ε ˙ was 0.75–1 on the power dissipation map. At high temperatures and a small strain rate, dynamic recrystallization easily occurred. The TEM analyses showed that nano-scale M23C6 and Cr2N precipitated at the grain boundary, and NbC with a diameter of approximately 150 nm appeared along the grain boundary, resulting in grain boundary strengthening. The phase precipitation results were consistent with the Thermo-Calc calculation results. The nitrogen solid solution in the steel promoted the precipitation of nitrides, which caused grain boundary strengthening. Thus, the grain boundary stress increased and wedge-shaped grain boundary cracks formed.

Constitutive and Processing Map Analyses of Stainless Steel 316 under Hot Compression

2013 ◽  
Vol 378 ◽  
pp. 178-183
Author(s):  
Chui Hung Chiu ◽  
Horng Yu Wu ◽  
Cheng Tao Wu
Keyword(s):  
Stainless Steel ◽  
Flow Stress ◽  
Constitutive Equation ◽  
Strain Rate ◽  
Power Dissipation ◽  
Hot Deformation ◽  
Processing Map ◽  
Constitutive Law ◽  
Hyperbolic Sine ◽  
Stainless Steel 316

Hot deformation characteristics of stainless steel 316 were investigated at elevated temperatures. Hot compressive tests were carried out in the temperature and strain rate ranges from 800 to 1100 °C and 0.001 to 1 s1, respectively. The flow behaviors showed that the softening mechanisms were related to the dynamic recovery (DRV) and dynamic recrystallization (DRX). The constitutive equation relating flow stress, temperature, and strain rate was obtained based on the peak stress. Constitutive equation was constructed according to the hyperbolic sine constitutive law. The flow stress of stainless steel 316 was fitted well by the constitutive equation of the hyperbolic sine function. The constitutive analysis suggested that the hot deformation mechanism of the stainless steel was dislocation creep. The processing map obtained at a strain of 0.5 exhibited two domains with local maximum efficiency of power dissipation. Variation in efficiency of power dissipation was associated with the variation in ZenerHollomon parameter (Z).

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.

Processing Map of Mg-13Al-3Ca-3Zn-1Nd-0.2Mn Magnesium Alloy

2014 ◽  
Vol 941-944 ◽  
pp. 48-53
Author(s):  
Wei Chen ◽  
Gang Chen ◽  
Jing Zhai ◽  
Li Ma
Keyword(s):  
Magnesium Alloy ◽  
Strain Rate ◽  
Power Dissipation ◽  
Processing Map ◽  
Strain Rate Range ◽  
Compression Tests ◽  
Temperature Range ◽  
Suitable Temperature ◽  
Instability Map ◽  
Flow Stress Data

Compression tests of Mg-13Al-3Ca-3Zn-1Nd-0.2Mn Magnesium alloy as-extruded had been performed in the compression temperature range from 200°C to 400°C and the strain rate range from 0.001 s−1 to 10 s−1 and the flow stress data obtained from the tests were used to develop the power dissipation map, instability map and processing map. The most unsuitable zones in the power dissipation map including 200°C - 315°C and 0.01s-1- 0.1s-1 zone, 315°C - 400°C and 0.001s-1- 0.01s-1zone and 340°C - 360°C and 0.32 s-1- 0.56 s-1zone. The most unsuitable zones in the instability map are 310°C - 400°C, 0.001s-1to 0.56 s-1zone and 330°C - 400°C, 1s-1to 10 s-1zone. The most suitable temperature range is 330°C - 400°C and most optimal strain rate ranges are 1 s-1- 10 s-1and 0.001s-1- 0.56 s-1.

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