Plastic Behavior of Metals at Large Strains: Experimental Studies Involving Simple Shear

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
E. F. Rauch
Keyword(s):  
Grain Size ◽  
Grain Refinement ◽  
Simple Shear ◽  
Equal Channel Angular Extrusion ◽  
Experimental Studies ◽  
Low Carbon Steel ◽  
Stage Iv ◽  
Large Strains ◽  
Plastic Behavior ◽  
Low Carbon

Two experimental devices that promote simple shear are used to investigate the plastic behavior of metals under very large strains. First, researches on the anisotropic behaviors of sheets of metals performed with the help of the planar simple shear test are reviewed. In particular, it is shown that, with this device, stage IV may be reached and analyzed on polycrystals as well as on single crystals. The second part is devoted to equal channel angular extrusion, which is known to promote grain refinement after several passes. A direct comparison of the crystallographic textures measured on sheared and on extruded samples confirms that the extrusion promotes massively simple shear. Besides, the grain refinement is measured with a dedicated transmission electron microscopy (TEM) attachment. It is shown that the grain size decreases regularly for a low carbon steel as well as for copper, down to around 1 μm. It is argued that the sustained hardening in stage IV is a mechanical signature of the grain size decrease. The trend is interpreted and reproduced quantitatively with the help of a simple modeling approach.

Microstructure and Mechanical Properties of Nb Alloyed Steel Processed by Hot Equal Channel Angular Extrusion

2016 ◽  
Vol 879 ◽  
pp. 2528-2531
Author(s):  
Akira Yanagida ◽  
Ryo Aoki ◽  
Masataka Kobayashi
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Carbon Steel ◽  
Equal Channel Angular Extrusion ◽  
Low Carbon Steel ◽  
Total Elongation ◽  
Low Carbon ◽  
Angular Extrusion ◽  
Ferrite Grain Size

A Nb alloyed low carbon steel was processed by hot equal channel angular extrusion (ECAE) and following transformation. The workpieces were heated up to the 960°C in the furnace for 10 min within the container block. Before extrusion, the die was preheated to 400oC. The workpiece was cooled in the die after ECAE process. 1 pass and 2 pass via route C were conducted at a speed of 32mm/s, the inter-pass time is about 2 sec. The sample of average ferrite grain size of about 2μm, a tensile strength of 800MPa, a total elongation about 20% is produced after 2 pass ECAE processed and subsequent cooling.

Influence of Grain Size on Bake Hardenability for Low Carbon Steel by Internal Friction Method

2014 ◽  
Vol 665 ◽  
pp. 72-75
Author(s):  
Wei Juan Li ◽  
Heng Yi Zhang ◽  
Hao Fu ◽  
Jian Ping Zhang ◽  
Xiang Yu Qi
Keyword(s):  
Grain Size ◽  
Carbon Steel ◽  
Internal Friction ◽  
Grain Refinement ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Ebsd Technique ◽  
Friction Method ◽  
Different Grain Size ◽  
Bake Hardenability

We presented the comparative influence of two different grain size on bake hardenability for low carbon steel dependent internal friction (IF) spectra. Samples that had a ferrite structure consisting of two peaks and a linear background. Analyzed the grain size and grain boundary length of low carbon steel by EBSD technique. The results showed that: the grain refinement increased the number of initial solute carbon atoms and the effect of movable dislocations pinning by carbon. So grain refinement of low carbon steel could enhance its bake hardening properties.

The Physical and Computer Modeling of Plastic Deformation of Low Carbon Steel in Semisolid State

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Marcin Hojny ◽  
Miroslaw Glowacki
Keyword(s):  
Computer Simulation ◽  
Low Carbon Steel ◽  
Mass Conservation ◽  
Analytical Form ◽  
Plastic Behavior ◽  
Volume Loss ◽  
Low Carbon ◽  
Compression Tests ◽  
Thermomechanical Model ◽  
Numerical Errors

This paper reports the results of theoretical and experimental work leading to the construction of a dedicated finite element method (FEM) system allowing the computer simulation of physical phenomena accompanying the steel sample testing at temperatures that are characteristic for integrated casting and rolling of steel processes, which was equipped with graphical, database oriented pre- and postprocessing. The kernel of the system is a numerical FEM solver based on a coupled thermomechanical model with changing density and mass conservation condition given in analytical form. The system was also equipped with an inverse analysis module having crucial significance for interpretation of results of compression tests at temperatures close to the solidus level. One of the advantages of the solution is the negligible volume loss of the deformation zone due to the analytical form of mass conservation conditions. This prevents FEM variational solution from unintentional specimen volume loss caused by numerical errors, which is inevitable in cases where the condition is written in its numerical form. It is very important for the computer simulation of deformation processes to be running at temperatures characteristic of the last stage of solidification. The still existing density change in mushy steel causes volume changes comparable to those caused by numerical errors. This paper reports work concerning the adaptation of the model to simulation of plastic behavior of axial-symmetrical steel samples subjected to compression at temperature levels higher than 1400°C. The emphasis is placed on the computer aided testing procedure leading to the determination of mechanical properties of steels at temperatures that are very close to the solidus line. Example results of computer simulation using the developed system are presented as well.

scholarly journals Exploring the Difference in Bainite Transformation with Varying the Prior Austenite Grain Size in Low Carbon Steel

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 988 ◽  
Author(s):  
Liangyun Lan ◽  
Zhiyuan Chang ◽  
Penghui Fan
Keyword(s):  
Grain Size ◽  
Prior Austenite ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Bainite Transformation ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
Austenite Grains ◽  
Prior Austenite Grain Size ◽  
Prior Austenite Grain

The simulation welding thermal cycle technique was employed to generate different sizes of prior austenite grains. Dilatometry tests, in situ laser scanning confocal microscopy, and transmission electron microscopy were used to investigate the role of prior austenite grain size on bainite transformation in low carbon steel. The bainite start transformation (Bs) temperature was reduced by fine austenite grains (lowered by about 30 °C under the experimental conditions). Through careful microstructural observation, it can be found that, besides the Hall–Petch strengthening effect, the carbon segregation at the fine austenite grain boundaries is probably another factor that decreases the Bs temperature as a result of the increase in interfacial energy of nucleation. At the early stage of the transformation, the bainite laths nucleate near to the grain boundaries and grow in a “side-by-side” mode in fine austenite grains, whereas in coarse austenite grains, the sympathetic nucleation at the broad side of the pre-existing laths causes the distribution of bainitic ferrite packets to be interlocked.

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