scholarly journals Influence of Annealing on Strength of Ultrafine Grained Low Carbon Steels by ECAP

2010 ◽  
Vol 638-642 ◽  
pp. 1899-1904 ◽  
Author(s):  
T. Akita ◽  
Masahide Gotoh ◽  
Sergey V. Dobatkin ◽  
Kazuo Kitagawa ◽  
Yukio Hirose
Keyword(s):  
Low Carbon Steel ◽  
Hardness Test ◽  
Carbon Steels ◽  
Low Carbon ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Thermal Reactions ◽  
Fine Grained ◽  
Angular Pressing ◽  
Ultrafine Grained

In the present study, ultra fine-grained low carbon steel samples were processed by equal channel angular pressing (ECAP). Mechanical properties of the specimens annealed statically at several temperatures were evaluated by tensile and hardness test. In addition, grain sizes of the specimens were measured by SEM-electron back scattering pattern (SEM-EBSP) and X-ray diffraction analysis. Differential scanning calorimetry (DSC) measurement also evaluated thermal reactions in anneal process of the specimen. As a result, the grain size was changed at the temperature between 550oC and 600oC drastically and the tensile strength also became lower at the same temperature. The relation between yield stress and averaged grain diameter of specimens obeyed the Hall-Petch relation except the normalized specimen. Behavior of grain growth and recovery in structural observation by EBSP corresponded to reaction signal of the DSC curve.

Ultrafine Grained Structure Formation in Low Carbon Steel Processed by SPD

2010 ◽  
Vol 654-656 ◽  
pp. 1223-1226 ◽  
Author(s):  
Jozef Zrník ◽  
Sergey V. Dobatkin ◽  
George Raab ◽  
Libor Kraus
Keyword(s):  
Carbon Steel ◽  
Grain Refinement ◽  
Structural Characteristics ◽  
Structure Refinement ◽  
Deformation Behaviour ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Ultrafine Grained Structure ◽  
Angular Pressing ◽  
Ultrafine Grained

The present work deals with grain refinement in low carbon steel (AISI 1010) by severe plastic deformation (SPD). The effect of structure modification was evaluated with respect to thermomechanical (TM) treatment of steel prior to SPD. The grain refinement was accomplished during warm angular channel pressing (ECAP) at 300°C. The evolution of microstructure during equal channel angular pressing (ECAP) was studied using SEM and TEM of thin foils. Ultrafine-grained structure development is described in relation to strainintroduced. At lower strain applied, the subgrain and/or polygonized structure was frequently found. Due to increased deformation temperature, the dynamic recovery contributed to structure refinement in both structural states. The amount of high angle boundaries increased with higher ECAP strain and was higher in TM-processed steel. There was only an indistinctive difference in structure refinement, considering different initial structures of the steel.The deformation behaviour of UFG steel in dependence on processing conditions was evaluated by a tensile test and correlated with structural characteristics.

The Evolution of Structure and Mechanical Properties of Fe-Mn-V-Ti-0,1C Low-Carbon Steel Subjected to Severe Plastic Deformation and Subsequent Annealing

2012 ◽  
Vol 715-716 ◽  
pp. 994-999 ◽  
Author(s):  
Galina G. Zakharova ◽  
Elena G. Astafurova ◽  
Evgeny V. Naydenkin ◽  
Georgy I. Raab ◽  
Sergey V. Dobatkin
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
High Pressure Torsion ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Average Size

The present work deals with the evolution of mechanical properties and structure of low-carbon Fe-1,12Mn-0,08V-0,07Ti-0,1C (wt.%) steel after severe plastic deformation (SPD) and high-temperature annealing. Steel in initial ferritic-pearlitic state was deformed by equal channel angular pressing (ECAP) at T=200°C and high pressure torsion (HPT) at room temperature. The evolution of ultrafine grained structure and its thermal stability were investigated after annealing at 400-700°C for 1 hour. The results shown that SPD leads to formation of structure with an average size of (sub-) grain of 260 nm after ECAP and 90 nm after HPT. Ultrafine grained structures produced by SPD reveal a high thermal stability up to 500°C after ECAP and 400°C after HPT. At higher annealing temperatures a growth of structural elements and a decrease in microhardness were observed.

Formation of Ferrite-Cementite Ultrafine Grained Microstructure by Warm Compression for SM490 Martensite Steel

2007 ◽  
Vol 558-559 ◽  
pp. 539-544
Author(s):  
J.H. Li ◽  
Ping Guang Xu ◽  
Yo Tomota ◽  
Yoshitaka Adachi
Keyword(s):  
Dynamic Recrystallization ◽  
Low Carbon Steel ◽  
Block Size ◽  
Low Carbon ◽  
Fine Grained ◽  
Orientation Imaging ◽  
Ultrafine Grained ◽  
Different Temperatures ◽  
Dynamic Recrystallization Behavior ◽  
Ultrafine Grained Microstructure

The low carbon steel, SM490 was austenized at different temperatures followed by quenching into water to obtain martensite microstructures with different grain sizes. Then specimens were heated up to 600°C followed by warm-compression at έ=1.7x10-3 s-1 (strain rate) to investigate the dynamic recrystallization behavior. The influence of pre-tempering before compression was also investigated. The microstructure observations were performed with FE-SEM and orientation imaging analysis with EBSD. It is confirmed that the dynamic recrystallization occurred in the tempered martensite as well as the as-quenched marteniste, resulting in fine grained ferrite microstructure with about 2μm. The dynamic recrystallization grain size is hardly dependent on the block size of initial martensite.

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