scholarly journals Double twist torsion testing to determine the non recrystallization temperature

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Trevor J. Ballard ◽  
John G. Speer ◽  
Kip O. Findley ◽  
Emmanuel De Moor
Keyword(s):  
Thermomechanical Processing ◽  
Torsion Test ◽  
Recrystallization Temperature ◽  
Testing Technique ◽  
Traditional Methods ◽  
Torsion Testing ◽  
Austenite Recrystallization ◽  
Fractional Softening ◽  
Hot Torsion ◽  
Multiple Deformation

AbstractA double-twist torsion testing technique has been developed using a 316 stainless steel as an exemplar material to experimentally assess recrystallization behavior and determine the non-recrystallization temperature (Tnr). This new method was compared to the traditional methods of double-hit compression and multi-step hot torsion testing. The double-twist torsion test allows Tnr to be related to the extent of austenite recrystallization through measurements of fractional softening while accommodating multiple deformation and recrystallization steps with a single specimen. The double-twist torsion test resulted in average Tnr values similar to those determined with multi-step hot torsion, and a partially recrystallized microstructure was observed in the vicinity of the calculated Tnr for all three methods. The ability of the double-twist torsion test to relate the experimental Tnr to the evolution of austenite recrystallization via fractional softening measurements while incorporating effects of multiple deformation steps offers an advantage over traditional methods for quantifying changes in austenite recrystallization during thermomechanical processing.

scholarly journals Analysis of Recrystallization and Strain-Induced Precipitation on High Nb- and N-Bearing Austenitic Stainless Steel

2014 ◽  
Vol 922 ◽  
pp. 700-705 ◽  
Author(s):  
Mariana B.R. Silva ◽  
J. Gallego ◽  
Jose María Cabrera ◽  
O. Balancin ◽  
Alberto Moreira Jorge
Keyword(s):  
Thermomechanical Processing ◽  
Extraction Replica ◽  
Carbon Extraction Replica ◽  
Thin Foils ◽  
Transmission Electron ◽  
Hot Torsion ◽  
Deformation Pass ◽  
Mechanical Properties And Corrosion ◽  
Multiple Deformation ◽  
Soaking Temperature

The mechanical properties and corrosion resistance of stainless steels are due to the combined effect of chemical composition and thermomechanical processing. The objective of this study was to investigate the interaction precipitation-recrystallization of an austenitic steel with high additions of nitrogen and niobium through continuous-cooling multiple deformation hot-torsion tests. Samples were heated up to a soaking temperature of 1250oC and kept at this temperature for 5 minutes, and then deformed during cooling. The deformation pass was 0.3 with a strain rate of 1 s-1and interpass times of 20 or 50 s. The evolution of the microstructure was investigated by optical, EBSD and transmission electron microscopy, using thin foils and carbon extraction replica samples. The results showed that some precipitates were not dissolved after reheating and the presence of niobium-and chromium-rich particles after processing was confirmed. The strain accumulation with the interpass time of 20 s yielded finer precipitation and improved grain refinement than observed after 50 s. Some interaction of the precipitates with dislocations and grain boundary could be evidenced.

scholarly journals Hot Ductility of TiNb IF Steel Slab after Hot Torsion Testing

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 752 ◽  
Author(s):  
Konrádyová ◽  
Longauerová ◽  
Jonšta ◽  
Jonšta ◽  
Longauer ◽  
...  
Keyword(s):  
Temperature Cycling ◽  
Hot Ductility ◽  
If Steel ◽  
Cast Slab ◽  
Torsion Testing ◽  
Steel Slab ◽  
Temperature Dependences ◽  
Hot Torsion ◽  
Average Size ◽  
20 Nm

The aim of the work was to evaluate the hot ductility loss in TiNb stabilized IF steel directly from the continuously-cast slab using hot torsion testing (plastometry) in the temperature range 600–1250 °C according to the basic programme, and also after temperature cycling. A good match of the temperature dependences of number of turns to failure (Nf) and intensity of deformation Se was confirmed. In both cases, the existence of three temperature areas with decrease in plasticity to a minimum was confirmed. The two-stage temperature cycling according to the CT1150 and CT900 programmes mostly resulted in a decrease in plasticity compared to the basic programme. The most significant effect of cycling was related to the CT900 programme below the maximum plasticity in the base programme at 850 °C. A less pronounced decrease was observed for CT1150 cycling below the maximum plasticity in the base program at 1050 °C. In the case of CT1150 cycling, more complex particles were observed at the fractures compared with the basic programme, namely carbonitrides of Ti and Nb in combination with oxisulfides respectively, then Ti nitrides with oxisulfides or oxides and, in addition, complex (Fe,Nb)P4, (Ti,Nb)3S4 type particles. Their mean size determined statistically using TEM was much finer, only 20 nm versus 42 nm in the basic programme. Similarly, CT900 cycling revealed finer particles with an average size of 37 nm compared to 105 nm in the basic programme. The observed particles were Al oxides, Ti(N,C) and (Ti,Nb)2S, in contrast to the particles probably of TiFe and FeMnS in the basic programme. The decrease in plasticity corresponded to the finer particles, newly created in the temperature cycling.

Application of Torsion Test for Determination of Rheological Properties of 5019 Aluminium Alloy

2016 ◽  
Vol 682 ◽  
pp. 356-361 ◽  
Author(s):  
Konrad Laber ◽  
Anna Kawałek ◽  
Sylwester Sawicki ◽  
Henryk Dyja ◽  
Jacek Borowski ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Mathematical Modelling ◽  
Aluminium Alloy ◽  
Rheological Properties ◽  
Torsion Test ◽  
Hot Torsion ◽  
Hot Torsion Test

The paper presents the results of the study aimed at determination of plasticity of hard-deformed aluminium alloy grade 5019 in terms of parameters characteristic for the process of extrusion. The examinations were carried out in hot torsion test. Using the developed mathematical model of the analyzed alloy the mathematical modelling of torsion test was also performed.

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