Static Softening Behavior of Low Carbon High Niobium Microalloyed Steel

2020 ◽  
Vol 990 ◽  
pp. 36-43
Author(s):  
Dian Xiu Xia ◽  
Heng Ke Du ◽  
Xin En Zhang ◽  
Xiu Cheng Li ◽  
Ying Chao Pei
Keyword(s):  
Deformation Temperature ◽  
Static Recrystallization ◽  
Microalloyed Steel ◽  
Testing Machine ◽  
Low Carbon ◽  
High Deformation ◽  
Softening Behavior ◽  
Test Steel ◽  
Static Softening ◽  
Niobium Microalloyed Steel

The MMS-200 thermal simulation testing machine was used to study the static softening behavior of low carbon high niobium microalloyed steel. The effect of niobium to the static recrystallization softening behavior of the microalloy steel had been analyzed by establishing the kinetics model of static recrystallization and the micro-morphology of precipitates. The results indicated that: the static softening behavior of the tested steel significantly influenced by the deformation temperature and the interval pass time of the rolling processing. At relatively high deformation temperature and long interval pass time, the ratio of static softening was increased. Then the deformation temperature was lower to 950°C, and the static softening behavior of the test steel was ceased. But when the deformation temperature was higher than 1000°C, the static softening behavior of the test steel completely occurred. The activation energy of the test steel was 325·mol-1 by the established model calculated.

Experimental investigation on static recrystallization behavior of a low carbon Nb–V–Ti microalloyed steel

2021 ◽  
Vol 118 (2) ◽  
pp. 202
Author(s):  
Fei Li ◽  
Liwen Zhang ◽  
Chi Zhang ◽  
Qing Yang ◽  
Chaoqun Li ◽  
...  
Keyword(s):  
Grain Size ◽  
Strain Rate ◽  
Deformation Temperature ◽  
Static Recrystallization ◽  
Microalloyed Steel ◽  
Pipeline Steel ◽  
Low Carbon ◽  
Compression Tests ◽  
X70 Pipeline Steel ◽  
Deformation Parameters

The static recrystallization (SRX) behavior of a low carbon Nb–V–Ti microalloyed steel X70 was investigated by two-pass hot compression tests. The compression tests were carried out at deformation temperatures of 1000–1150 °C, strain rates of 0.01–5 s−1, pre-strains of 0.1–0.2 and interval times of 1–50 s. The effects of deformation parameters on SRX behavior were analyzed. The experimental results showed that deformation temperature, pre-strain and strain rate had significant influence on SRX fraction, while initial grain size had a smaller impact. The effects of deformation parameters on SRX microstructure were discussed, and the microstructure evolution process was analyzed. Higher deformation temperature, strain rate and pre-strain lead to larger SRX fraction. The kinetics and recrystallized grain size models for SRX of X70 pipeline steel were developed. Comparison between the predicted results and the experimental ones indicated that the established equations could give a reasonable description for SRX behavior of X70 pipeline steel.

Study on the Static Recrystallization Behavior of Thermal Deformation of Austenitic Stainless Steel for Nuclear Power

2010 ◽  
Vol 658 ◽  
pp. 165-168 ◽  
Author(s):  
Jie Liu ◽  
Guang Wei Fan ◽  
Pei De Han ◽  
Jian Feng Yang ◽  
Jian Sheng Liu ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Nuclear Power ◽  
Thermal Deformation ◽  
Static Recrystallization ◽  
True Strain ◽  
Testing Machine ◽  
Softening Behavior ◽  
304 Austenitic Stainless Steel ◽  
Static Softening

Dual-interval compression test was carried out with Gleeble-1500D thermal simulation testing machine on the 304 austenitic stainless steel used for nuclear power. The first-interval strain was 0.3, and the second 0.05, and the dual-interval strain rates is 0.1s-1, dual-interval temperatures of thermal deformation were 950°C, 1000°C, and 1050°C respectively. The softening behavior with thermal deformation at different temperatures and time intervals was studied. It was shown in the study that the occurrence of static softening was very easy for the material; the activation energy for static recrystallization Qrex was 383.45 kJ / mol in case of true strain of 0.3 and strain rate of 0.1s-1.

Study of Nb Solubility in Hot Charging Process

2021 ◽  
Vol 1016 ◽  
pp. 832-839
Author(s):  
Beatriz López ◽  
Beatriz Pereda ◽  
Felipe Bastos ◽  
J.M. Rodriguez-Ibabe
Keyword(s):  
Static Recrystallization ◽  
Solute Drag ◽  
Dissolution Behavior ◽  
Drag Effect ◽  
Experimental Procedure ◽  
Solute Drag Effect ◽  
Softening Behavior ◽  
Static Softening ◽  
Indirect Evaluation ◽  
Do So

The aim of this work is to investigate the dissolution behavior of Nb in hot charging hot rolling configurations. To do so, an indirect experimental procedure is used to quantify the amount of Nb present in solution before rolling. The method is based on the effect of dissolved Nb on static recrystallization kinetics due to its solute drag effect. After different thermal cycles, simulating cold and hot charging conditions, double hit torsion tests have been performed with a 0.23%C steel microalloyed with 0.03% Nb. By means of these tests, the static softening behavior has been determined. Comparison of the recrystallization times allows indirect evaluation of the amount of Nb in solid solution after each treatment. The results have been correlated with the precipitation state of the samples.

scholarly journals Interaction between Recrystallization and Precipitation during Multipass Rolling in a Low Carbon Niobium Microalloyed Steel.

2001 ◽  
Vol 41 (11) ◽  
pp. 1373-1382 ◽  
Author(s):  
R. Abad ◽  
A. I. Fernández ◽  
B. López ◽  
J. M. Rodriguez-Ibabe
Keyword(s):  
Microalloyed Steel ◽  
Low Carbon ◽  
Niobium Microalloyed Steel

scholarly journals Determination of Non-Recrystallization Temperature for Niobium Microalloyed Steel

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2639
Author(s):  
Mohammad Nishat Akhtar ◽  
Muneer Khan ◽  
Sher Afghan Khan ◽  
Asif Afzal ◽  
Ram Subbiah ◽  
...  
Keyword(s):  
Microalloyed Steel ◽  
Casting Process ◽  
Rolling Process ◽  
Recrystallization Temperature ◽  
Microalloyed Steels ◽  
Low Carbon ◽  
Nb Microalloyed Steel ◽  
Niobium Microalloyed Steel ◽  
Multiple Hit ◽  
Deformation Tests

In the present investigation, the non-recrystallization temperature (TNR) of niobium-microalloyed steel is determined to plan rolling schedules for obtaining the desired properties of steel. The value of TNR is based on both alloying elements and deformation parameters. In the literature, TNR equations have been developed and utilized. However, each equation has certain limitations which constrain its applicability. This study was completed using laboratory-grade low-carbon Nb-microalloyed steels designed to meet the API X-70 specification. Nb- microalloyed steel is processed by the melting and casting process, and the composition is found by optical emission spectroscopy (OES). Multiple-hit deformation tests were carried out on a Gleeble® 3500 system in the standard pocket-jaw configuration to determine TNR. Cuboidal specimens (10 (L) × 20 (W) × 20 (T) mm3) were taken for compression test (multiple-hit deformation tests) in gleeble. Microstructure evolutions were carried out by using OM (optical microscopy) and SEM (scanning electron microscopy). The value of TNR determined for 0.1 wt.% niobium bearing microalloyed steel is ~ 951 °C. Nb- microalloyed steel rolled at TNR produce partially recrystallized grain with ferrite nucleation. Hence, to verify the TNR value, a rolling process is applied with the finishing rolling temperature near TNR (~951 °C). The microstructure is also revealed in the pancake shape, which confirms TNR.

Effect of heating rate on reaustenitisation of low carbon niobium microalloyed steel

2008 ◽  
Vol 24 (3) ◽  
pp. 266-272 ◽  
Author(s):  
San D. Martín ◽  
de T. Cock ◽  
A. García-Junceda ◽  
F. G. Caballero ◽  
C. Capdevila ◽  
...  
Keyword(s):  
Heating Rate ◽  
Microalloyed Steel ◽  
Low Carbon ◽  
Niobium Microalloyed Steel
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