scholarly journals Full-Field Temperature Measurement of Stainless Steel Specimens Subjected to Uniaxial Tensile Loading at Various Strain Rates

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5259
Author(s):  
Krzysztof Żaba ◽  
Tomasz Trzepieciński ◽  
Stanislav Rusz ◽  
Sandra Puchlerska ◽  
Maciej Balcerzak

This article presents a study on the effect of strain rate, specimen orientation, and plastic strain on the value and distribution of the temperature of dog-bone 1 mm-thick specimens during their deformation in uniaxial tensile tests. Full-field image correlation and infrared thermography techniques were used. A titanium-stabilised austenitic 321 stainless steel was used as test materials. The dog-bone specimens used for uniaxial tensile tests were cut along the sheet metal rolling direction and three strain rates were considered: 4 × 10−3 s−1, 8 × 10−3 s−1 and 16 × 10−3 s−1. It was found that increasing the strain rate resulted in the intensification of heat generation. High-quality regression models (Ra > 0.9) developed for the austenitic 321 steel revealed that sample orientation does not play a significant role in the heat generation when the sample is plastically deformed. It was found that at the moment of formation of a necking at the highest strain rate, the maximum sample temperature increased more than four times compared to the initial temperature. A synergistic effect of the strain hardening exponent and yield stress revealed that heat is generated more rapidly towards small values of strain hardening exponent and yield stress.

Author(s):  
Cunjian Miao ◽  
Yaxian Li ◽  
Jinyang Zheng

Cold stretching (pressure strenghtening) technique has been widely used in austenitic stainless steel pressure vessels in order to increase the proof strength and lighten the weight of the vessels. Cold stretching technique is performed by applying the strengthening pressure under a specified strain rate. Plastic deformation in the process will lead to martensite transformation and may influence material’s strength and ductility. Cold stretching tests of EN 1.4301 stainless steel are carried out at different quasi-static strain rates of 10−3 and 10−5/s, following the uniaxial tensile tests at the same strain rate of 2.5×10−3/s. The α′-martensite transformation is detected by magnetic measurement, meanwhile the work-hardening rate, the flow stress and the mechanical properties of material are studied and the results are presented.


2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Yong Peng ◽  
Xuanzhen Chen ◽  
Shan Peng ◽  
Chao Chen ◽  
Jiahao Li ◽  
...  

In order to study the dynamic and fracture behavior of 6005 aluminum alloy at different strain rates and stress states, various tests (tensile tests at different strain rates and tensile shearing tests at five stress states) are conducted by Mechanical Testing and Simulation (MTS) and split-Hopkinson tension bar (SHTB). Numerical simulations based on the finite element method (FEM) are performed with ABAQUS/Standard to obtain the actual stress triaxialities and equivalent plastic strain to fracture. The results of tensile tests for 6005 Al show obvious rate dependence on strain rates. The results obtained from simulations indicate the feature of nonmonotonicity between the strain to fracture and stress triaxiality. The equivalent plastic strain reduces to a minimum value and then increases in the stress triaxiality range from 0.04 to 0.30. A simplified Johnson-Cook (JC) constitutive model is proposed to depict the relationship between the flow stress and strain rate. What is more, the strain-rate factor is modified using a quadratic polynomial regression model, in which it is considered to vary with the strain and strain rates. A fracture criterion is also proposed in a low stress triaxiality range from 0.04 to 0.369. Error analysis for the modified JC model indicates that the model exhibits higher accuracy than the original one in predicting the flow stress at different strain rates. The fractography analysis indicates that the material has a typical ductile fracture mechanism including the shear fracture under pure shear and the dimple fracture under uniaxial tensile.


2011 ◽  
Vol 311-313 ◽  
pp. 2014-2019
Author(s):  
Ruo Dong Lu ◽  
He Yang ◽  
Heng Li ◽  
Ze Kang Wang ◽  
Mei Zhan ◽  
...  

By the uniaxial tensile tests of both the arc and tube section samples, the strain hardening curves of 21-6-9 high-strength stainless steel tube(HSST) are obtained. Considering that the uniform plastic deformation stage of the curve is short and the flow stress in large strain area is unknown for this tube, different strain hardening models have been established based on single and piecewise functions, respectively. By comparing the experimental results and the numerical ones in terms of load-displacement curves, it shows the constitutive model achieved by three Swift fitting functions can better characterize the strain hardening response of the 21-6-9 HSST in large strain region.


2012 ◽  
Vol 430-432 ◽  
pp. 256-259 ◽  
Author(s):  
Yang Yang ◽  
Chun Fu Li ◽  
Kai Hong Song

TWIP steel containing 0.21% C, 24.4% Mn, 0.9% Si, 1.84% Al, 4.61% Cr, 1.89% Ni, 0.41% Mo and 0.012% Nb was investigated. Tensile tests of this steel were performed in the strain rate range of 10−4–10−3 s−1. Results indicate that tensile properties of TWIP steel at room temperature are sensitive to strain rate in the studied range. Analyses on the relationship between strain–hardening exponent and strain rates show that the formation of twins during deformation greatly affects the strain–hardening behavior of TWIP steels.


2020 ◽  
Vol 93 (1) ◽  
pp. 183-194 ◽  
Author(s):  
Lingmei Guo ◽  
Yang Wang

ABSTRACT The effects of strain rate and temperature on the tensile behavior of silicone rubber were investigated. The quasi-static uniaxial tensile experiments were conducted using an electromechanical testing system, and the high-rate uniaxial tensile tests were performed employing a modified split Hopkinson tension bar technique for low-strength and low-impedance materials. The tensile responses were obtained at strain rates of 0.001–1400 s−1 and temperatures ranging from −50 to 50 °C. The experiments reveal that the tensile stress–strain behavior of silicone rubber is nonlinear and highly dependent on strain rate and temperature. The values of stiffness and nominal stress at a given elongation increase with increased strain rate and decrease with increasing temperature. It is appropriate to postulate that the tensile response at high strain rates arises from the combination of hyperelasticity and viscoelasticity. According to the incompressibility assumption, a phenomenologically inspired visco-hyperelastic model was proposed to describe the constitutive behavior of silicone rubber over wide ranges of strain rates and temperatures.


1986 ◽  
Vol 108 (4) ◽  
pp. 344-353 ◽  
Author(s):  
M. G. Stout ◽  
P. S. Follansbee

Sheet and rod stock of 304L stainless steel were tested in uniaxial tension and compression at strain rates between 10−4 s−1 and 104 s−1. To evaluate the yield locus behavior of the sheet material, multiaxial experiments were performed at a strain rate of 10−3 s−1. We have analyzed these results in terms of existing strain-rate sensitivity, work hardening, and yield locus models. Strain-rate sensitivity was found to follow a thermal activation law over the entire range of strain rates used in this investigation. The best description of strain hardening did depend on the strain range to which the data were fit. The Voce law was the most accurate at large strains (ε > 0.40), whereas at small strains, in the vicinity of yield, the laws of either Swift or Ludwik were the most accurate. A simple power law description of work hardening was inadequate over all levels of strain. We examined a number of yield criteria, both isotropic and anisotropic, with respect to the biaxial yield behavior. Bassani’s yield criterion gave the best fit to our experimental results. However, the simple von Mises yield function also gave an acceptable prediction of yield strength and direction of current plastic strain rate. The yield criteria of Hill, both the quadratic and nonquadratic versions, did not match the experimental data. We feel that these results have direct application to the selection of the proper constitutive laws for the finite element modeling of the deformation of 304L stainless steel.


Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1090 ◽  
Author(s):  
Nae Tak ◽  
Jung-Seok Kim ◽  
Jae-Yong Lim

An energy-based low-cycle fatigue model was proposed for applications at a range of temperatures. An existing model was extended to the integrated approach, incorporating the simultaneous effects of strain rate and temperature. A favored material at high temperature, type 316L stainless steel, was selected in this study and its material characteristics were investigated. Tensile tests and low-cycle fatigue tests were performed using several strain rates at a temperature ranging from room temperature to 650 °C. Material properties were obtained in terms of temperature using the displacement-controlled tensile tests and further material response were investigated using strain-controlled tensile tests. Consequently, no pronounced reduction in strengths occurred at temperatures between 300 and 550 °C, and a negative strain rate response was observed in the temperature range. Based on the low-cycle fatigue tests by varying strain rates and temperature, it was found that a normalized plastic strain energy density and a strain-rate modified cycle were successfully correlated. The accuracy of the model was discussed by comparing between predicted and experimental lives.


2013 ◽  
Vol 455 ◽  
pp. 159-162 ◽  
Author(s):  
Zhi Qiang Xu ◽  
Yin Zhong Shen

Serrated flow behavior of the 316LN austenitic stainless steel was investigated through tensile tests at initial strain rates of 2×10-5 to 10-4 s-1 at temperatures ranging from room temperature to 1048 K. Serrated flow occurred at room temperature and 6981048K at the strain rate of 2×10-4 s-1, as well as at temperatures of 623673 K at the strain rate of 2×10-5 s-1. Type A, A+B, C and E serrations appeared. The activation energy for the occurrence of serrated flow at high temperatures was about 327 kJ/mol. The dynamic strain aging caused by the interaction between substitutional solute Cr atoms and moving dislocations is considered as the mechanism of serrated flow at the temperatures higher than 973 K.


Metals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 736 ◽  
Author(s):  
Farid Abed ◽  
Akrum Abdul-Latif ◽  
Ayatollah Yehia

The objective of this paper is to investigate the mechanical response of EN08 steel at quasi-static and dynamic strain rates. Uniaxial tensile tests under quasi-static regime (from 0.0015 s−1 to 0.15 s−1) are conducted on EN08 steel at a range of temperatures between 298 K and 923 K. Dynamic compression tests are also performed by using a drop hammer and by considering different masses and heights to study the material response at strain rates up to 800 s−1. Through the stress-strain responses of EN08 steel, a strong dependency of the yield stress as well as the ultimate strength on the strain rate and temperature is recognized. Furthermore, the strain hardening is highly affected by the increase of temperature at all levels of strain rate. The microstructure of the steel is also examined at a fracture by using SEM images to quantify the density of microdefects and define the damage evolution by using an energy-based damage model.


2021 ◽  
Vol 309 ◽  
pp. 01215
Author(s):  
M. Krishnamraju ◽  
Abhishek Kumar ◽  
Sushil Mishra ◽  
K Narasimhan

Austenitic stainless steel is one of the second generation advanced high strength steel which finds application in automobile, aerospace and cryogenic components. The component made of austenitic steel might operate in subzero temperature condition because of its excellent formability even at subzero temperature. In the present work several tensile tests were performed on austenitic stainless-steel sheet of thickness 1.2 mm at 0°C, -40°C, -80°C, -120°C and at different strain rates of 0.01/sec,0.001/sec,0.0001/sec. The resultant mechanical properties, like yield strength, tensile strength, elongation percent and strain hardening exponent, along with phase fractions and microstructural properties were analyzed to understand the reasons for change in mechanical properties, on comparing with room temperature properties. It was noticed that tensile strength is 635 Mpa, & strain hardening exponent is 0.38 at room temperature (25 °C) and tensile strength is 1236 Mpa, & strain hardening exponent is O.49 at -120°C. Similarly, XRD characterization revealed that strain induced martensite increased from zero percent at 25°C (room temperature) to 57 percent at-120°C Similarly EBSD characterization revealed that grain average misorientation which also increased from room temperature to-120°C.


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