Experimental and Numerical Investigations on Hot Deformation Behavior and Processing Maps for ASS 304 and ASS 316

AbstractA thorough understanding of hot deformation behavior plays a vital role in determining process parameters of hot working processes. Firstly, uniaxial tensile tests have been performed in the temperature ranges of 150 °C–600 °C and strain rate ranges of 0.0001–0.01s−1 for analyzing the deformation behavior of ASS 304 and ASS 316. The phenomenological-based constitutive models namely modified Fields–Backofen (m-FB) and Khan–Huang–Liang (KHL) have been developed. The prediction capability of these models has been verified with experimental data using various statistical measures. Analysis of statistical measures revealed KHL model has good agreement with experimental flow stress data. Through the flow stresses behavior, the processing maps are established and analyzed according to the dynamic materials model (DMM). In the processing map, the variation of the efficiency of the power dissipation is plotted as a function of temperature and strain rate. The processing maps results have been validated with experimental data.

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

Advances in Materials Science and Engineering ◽

10.1155/2015/427945 ◽

2015 ◽

Vol 2015 ◽

pp. 1-8 ◽

Cited By ~ 3

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.

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

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.578.202 ◽

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.

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Hot Deformation Behavior and Processing Maps of 7050 Aluminum Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.815.37 ◽

2013 ◽

Vol 815 ◽

pp. 37-42 ◽

Cited By ~ 3

Author(s):

Yu Juan Guo ◽

Lei Deng ◽

Xin Yun Wang ◽

Jun Song Jin ◽

Wen Wu Zhou

Keyword(s):

Strain Rate ◽

Hot Deformation ◽

Deformation Behavior ◽

Strain Rate Range ◽

Processing Maps ◽

Compression Tests ◽

Hot Deformation Behavior ◽

Temperature Range ◽

Optimal Processing ◽

Working Region

The hot deformation behavior of 7050aluminum alloy was investigated by hot compression tests in the temperature range of 573-773K and the strain rate ranging from 0.001s-1to 10 s-1.The flow curves showed that the flow stresses increase with the increase of strain rate or the decrease of temperature.In order to determine the optimal processing conditions, hot processing maps were established based on experimental data and Dynamic Materials Model. The processing maps indicate that instability occur at low temperature and high strain rate. The optimum hot working region is the domain in the temperature range of 673-723K and strain rate range of 0.001-0.01 s-1,where typical recrystallization was observed in the optical microstructures.

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The Hot Deformation Behavior and Hot Processing Map of CL60 Rail Wheel Steel

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.602-604.2006 ◽

2012 ◽

Vol 602-604 ◽

pp. 2006-2010

Author(s):

Fei Zhao ◽

Yan Yan ◽

Yong Hai Ren

Keyword(s):

Flow Stress ◽

Strain Rate ◽

Hot Deformation ◽

Deformation Behavior ◽

Wheel Steel ◽

Strain Rates ◽

Peak Strain ◽

Processing Maps ◽

Hot Deformation Behavior ◽

Experimental Conditions

The hot deformation behavior of CL60 rail wheel steel has been studied by employing both processing maps and microstructural observations. Tests are performed at temperatures of 800—1100°C and strain rates of 0.1s-1—5s-1 and the flow stress data obtained from the tests are used to develop processing maps. The microstructural evolution of deformed samples is also examined on the basis of optical microscopic observations. The result indicates that under experimental conditions this alloy shows dynamic recrystallization(RDX) characteristics during hot compression deformation. Both deformation temperatures and strain rates have obvious influence on flow stress and its corresponding peak strain, which increase gradually with decreasing temperature and increasing strain rate. RDX occurred at higher temperature and lower strain rate.

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

Materials Science Forum ◽

10.4028/www.scientific.net/msf.704-705.210 ◽

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.

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