Influence of Deformation Rate on Mechanical Response of an AISI 316L Austenitic Stainless Steel

2014 ◽  
Vol 922 ◽  
pp. 49-54
Author(s):  
Mattias Calmunger ◽  
Guo Cai Chai ◽  
Sten Johansson ◽  
Johan Moverare
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Power Plants ◽  
Elevated Temperatures ◽  
Strain Rates ◽  
Aisi 316L ◽  
Elongation To Failure

Austenitic stainless steels are often used for components in demanding environment. These materials can withstand elevated temperatures and corrosive atmosphere like in energy producing power plants. They can be plastically deformed at slow strain rates and high alternating or constant tensile loads such as fatigue and creep at elevated temperatures. This study investigates how deformation rates influence mechanical properties of an austenitic stainless steel. The investigation includes tensile testing using strain rates of 2*10-3/ and 10-6/s at elevated temperatures up to 700°C. The material used in this study is AISI 316L. When the temperature is increasing the strength decreases. At a slow strain rate and elevated temperature the stress level decreases gradually with increasing plastic deformation probably due to dynamic recovery and dynamic recrystallization. However, with increasing strain rate elongation to failure is decreasing. AISI 316L show larger elongation to failure when using a strain rate of 10-6/s compared with 2*10-3/s at each temperature. Electron channelling contrast imaging is used to characterize the microstructure and discuss features in the microstructure related to changes in mechanical properties. Dynamic recrystallization has been observed and is related to damage and cavity initiation and propagation.

Investigation on Hardening and Softening Behavior of Steel after Rapid Strain Rate Changes

2016 ◽  
Vol 716 ◽  
pp. 121-128 ◽  
Author(s):  
Jens Dierdorf ◽  
Johannes Lohmar ◽  
Gerhard Hirt
Keyword(s):  
Flow Stress ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Metal Forming ◽  
Elevated Temperatures ◽  
Relaxation Behavior ◽  
Rate Change ◽  
Strain Rates ◽  
Flow Curves ◽  
Strain Rate Change

The design of industrial hot metal forming processes nowadays is mostly carried out using commercial Finite Element (FE) software codes. For precise FE simulations, reliable material properties are a crucial factor. In bulk metal forming, the most important material property is the materials flow stress, which determines the form filling and the necessary forming forces. At elevated temperatures, the flow stress of steels is determined by strain hardening, dynamic recovery and partly by dynamic recrystallization, which is dependent on strain rate and temperature. To simulate hot forming processes, which are often characterized by rapidly changing strain rates and temperatures, the flow stress is typically derived from flow curves, determined at arbitrary constant temperatures and strain rates only via linear interpolation. Hence, the materials instant reaction and relaxation behavior caused by rapid strain rate changes is not captured during simulation. To investigate the relevance of the relaxation behavior for FE simulations, trails with abrupt strain rate change are laid out and the effect on the material flow stress is analyzed in this paper. Additionally, the microstructure evolution due to the strain rate change is investigated. For this purpose, cylinder compression tests of an industrial case hardening steel are conducted at elevated temperatures and different strain rates. To analyze the influence of rapid strain rate changes, changes by one power of ten are performed at a strain of 0.3. As a reference, flow curves of the same material are determined at the initial and final constant strain rate. To investigate the microstructure evolution, compression samples are quenched at different stages, before and after the strain rate change. The results show that the flow curves after the strain rate change tend to approximate the flow curves measured for the final strain rate. However, directly after the strain rate change significant differences between the assumed instant flow stress and the real material behavior can be observed. Furthermore, it can be shown that the state of dynamic recrystallization at the time of the strain rate change influences the material response and relaxation behavior resulting in different slopes of the investigated flow curves after the strain rate change.

Microstructure and Mechanical Properties of the Stainless Steels Obtained by Sintering Mixtures of AISI 316L and Silicon Powders

2006 ◽  
Vol 513 ◽  
pp. 35-50
Author(s):  
K. Sikorski ◽  
Agnieszka Szymańska ◽  
M. Sekuła ◽  
D. Kowalczyk ◽  
Jan Kazior ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Austenitic Steel ◽  
Stainless Steels ◽  
Hydrogen Atmosphere ◽  
Aisi 316L ◽  
Microstructure And Mechanical Properties ◽  
Steel Aisi

The aim of the study was to obtain a ferritic-austenitic stainless steel through sintering of the mixture of austenitic steel AISI 316L powders with silicon in the amount ranging from 1 to 7%. The pressed mixtures were sintered at 1240oC for 60 minutes under hydrogen atmosphere. The results of the silicon admixture on the density, porosity, microstructure and mechanical properties of the sintered specimens are discussed.

scholarly journals Tensile Properties and Microstructural Evolution of an Al-Bearing Ferritic Stainless Steel at Elevated Temperatures

Metals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 86 ◽  
Author(s):  
Ying Han ◽  
Jiaqi Sun ◽  
Yu Sun ◽  
Jiapeng Sun ◽  
Xu Ran
Keyword(s):  
Tensile Strength ◽  
Stainless Steel ◽  
Ultimate Tensile Strength ◽  
Yield Strength ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Ferritic Stainless Steel ◽  
Microstructural Evolution ◽  
Deformation Mechanism ◽  
Strain Rates

The influence of temperature and strain rate on the hot tensile properties of 0Cr18AlSi ferritic stainless steel, a potential structural material in the ultra-supercritical generation industry, was investigated at temperatures ranging from 873 to 1123 K and strain rates of 1.7 × 10−4–1.7 × 10−2 s−1. The microstructural evolution linked to the hot deformation mechanism was characterized by electron backscatter diffraction (EBSD). At the same strain rate, the yield strength and ultimate tensile strength decrease rapidly from 873 K to 1023 K and then gradually to 1123 K. Meanwhile, both yield strength and ultimate tensile strength increase with the increase in strain rate. At high temperatures and low strain rates, the prolonged necking deformation can be observed, which determines the ductility of the steel to some extent. The maximum elongation is obtained at 1023 K for the strain rates of 1.7 × 10−3 and 1.7 × 10−2 s−1, while this temperature is postponed to 1073 K once decreasing the strain rate to 1.7 × 10−4 s−1. Dynamic recovery (DRV) and continuous dynamic recrystallization (CDRX) are found to be the main softening mechanisms during the hot tensile deformation. With the increase of temperature and the decrease of strain rate (i.e., 1123 K and 1.7 × 10−4 s−1), the sub-grain coalescence becomes the main mode of CDRX that evolved from the sub-grain rotation. The gradual decrease in strength above 1023 K is related to the limited increase of dynamic recrystallization and the sufficient DRV. The area around the new small recrystallized grains on the coarse grain boundaries provides the nucleation site for cavity, which generally results in a reduction in ductility. Constitutive analysis shows that the stress exponent and the deformation activation energy are 5.9 and 355 kJ·mol−1 respectively, indicating that the dominant deformation mechanism is the dislocations motion controlled by climb. This work makes a deeply understanding of the hot deformation behavior and its mechanism of the Al-bearing ferritic stainless steel and thus provides a basal design consideration for its extensive application.

scholarly journals Impact Testing of Stainless Steel Material at Room and Elevated Temperatures

2007 ◽  
Author(s):  
Dana K. Morton ◽  
Spencer D. Snow ◽  
Tom E. Rahl ◽  
Robert K. Blandford
Keyword(s):  
Stainless Steel ◽  
Strain Rate ◽  
316L Stainless Steel ◽  
Elevated Temperatures ◽  
Impact Testing ◽  
Radioactive Material ◽  
Test Machine ◽  
Strain Rates ◽  
Steel Material ◽  
Stainless Steel Material

Stainless steels are used for the construction of numerous spent nuclear fuel or radioactive material containers that may be subjected to high strains and moderate strain rates during accidental drop events. Mechanical characteristics of these base materials and their welds under dynamic loads in the strain rate range of concern are not well documented. However, three previous papers [1, 2, 3] reported on impact testing and analysis results performed at the Idaho National Laboratory using 304/304L and 316/316L stainless steel base material specimens that began the investigation of these characteristics. The goal of the work presented herein is to add the results of additional tensile impact testing for dual-marked 304/304L and 316/316L stainless steel material specimens (hereafter referred to as 304L and 316L, respectively). Utilizing a drop-weight impact test machine and 1/4-inch to 1/2-inch thick dog-bone shaped test specimens, additional impact tests achieved target strain rates of 5, 10, and 22 per second at room temperature, 300, and 600 degrees Fahrenheit. Elevated true stress-strain curves for these materials at each designated strain rate and temperature are presented herein.

scholarly journals Mechanical properties of Austenitic Stainless Steel 304L and 316L at elevated temperatures

2016 ◽  
Vol 5 (1) ◽  
pp. 13-20 ◽  
Author(s):  
Raghuram Karthik Desu ◽  
Hansoge Nitin Krishnamurthy ◽  
Aditya Balu ◽  
Amit Kumar Gupta ◽  
Swadesh Kumar Singh
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Elevated Temperatures ◽  
Stainless Steel 304L
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