ON THE TRIAL MANUFACTURING OF HOT TORSION TESTING MACHINE

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.

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Effect of thermomechanical parameters on the critical strain for ultrafine ferrite formation through hot torsion testing

Materials Science and Engineering A ◽

10.1016/j.msea.2003.09.095 ◽

2004 ◽

Vol 367 (1-2) ◽

pp. 152-161 ◽

Cited By ~ 65

Author(s):

H Beladi ◽

G.L Kelly ◽

A Shokouhi ◽

P.D Hodgson

Keyword(s):

Critical Strain ◽

Torsion Testing ◽

Ferrite Formation ◽

Hot Torsion

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Design of 80000N·m Torsion Testing Machine

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.607.350 ◽

2014 ◽

Vol 607 ◽

pp. 350-353

Author(s):

Wei Li Yu

Keyword(s):

Control System ◽

Power Unit ◽

Testing Machine ◽

Electronic Control ◽

Control Manner ◽

Torsion Testing ◽

Mechanical Structure ◽

Electronic Control System

The article introduce the mechanical structure and the principles of 80000 N·m torsion testing machine, the structure and the principles of checking power unit of this kind of testing machines and the control manner and the principles of the electronic control system, than expound the benefits of the equipment and its application.

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Method for Evaluating Potential Maximum Shear Strain for a Fine Metal Wire in Torsion Testing

Experimental Techniques ◽

10.1007/s40799-020-00397-2 ◽

2020 ◽

Author(s):

S. Gondo ◽

H. Akamine ◽

R. Mitsui ◽

S. Kajino ◽

M. Asakawa ◽

...

Keyword(s):

Shear Strain ◽

Strain Distribution ◽

High Carbon Steel ◽

Testing Machine ◽

External Factors ◽

Maximum Shear Strain ◽

Internal Factors ◽

Torsion Testing ◽

The Difference ◽

Potential Maximum

Abstract The torsion number of drawn fine high carbon steel wires was measured through torsion testing. The angles between the scratches on the tested wire surface and its longitudinal axis were measured. The shear strain calculated from torsion number γt, shear strain at fractured point γf, and plastic shear strain γpc were evaluated. The following results were obtained. First, the shear strain distribution homogenized; further, torsion number per unit length N, γt, and γpc increased when decreasing the difference between γf and γpc where γpc subtracted from γf (=Δγfpc) > 0. Second, the external factors caused non-uniform shear strain distribution and reduction from the potential maximum shear strain, even for the wire that was hardly affected by the internal factors. The difference of shear strain non-uniformity caused a variation in reduction from the potential maximum shear strain. The internal factors included non-uniform microstructure and existence of inclusions and voids. The external factors were caused by the testing machine and setting of the sample. The potential maximum shear strain was obtained when the effects of internal and external factors were inhibited. Finally, two evaluation methods of the potential maximum shear strain were suggested. One method identifies a sample with a small Δγfpc, and a large γpc where Δγfpc > 0. This sample can be regarded as having the closest strain to the potential maximum shear strain. The other method determines γpc when Δγfpc is closest to 0. This value can be interpreted as plastic strain of the potential maximum shear strain.

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