scholarly journals Simplification of Hot Rolling Schedule in Ti-Microalloyed Steels with Optimised Ti/N Ratio

2010 ◽  
Vol 50 (6) ◽  
pp. 868-874 ◽  
Author(s):  
Manuel Gómez ◽  
Lucía Rancel ◽  
Pedro P. Gómez ◽  
José I. Robla ◽  
Sebastián F. Medina
Keyword(s):  
Hot Rolling ◽  
Microalloyed Steels ◽  
Rolling Schedule

Grain Size Modeling during Hot Rolling of a Nb Microalloyed Steel Beam

2013 ◽  
Vol 753 ◽  
pp. 397-402
Author(s):  
Emanuelle Garcia Reis ◽  
Ronaldo Barbosa
Keyword(s):  
Grain Size ◽  
Hot Rolling ◽  
Microalloyed Steels ◽  
Strain Rates ◽  
Rolling Schedule ◽  
Austenite Grain Size ◽  
Beneficial Effects ◽  
Size Evolution ◽  
Nb Microalloyed Steel ◽  
Two Stages

Hot rolling of beams is carried out essentially in two stages. Roughing is performed in a reversing mill at temperatures in the range of 1100 oC, at relatively low strain rates and with long interpass times. Finishing is carried out in a reversing two stand mill at temperatures in between 1000 and as low as 700 oC considering parts of the web in the last passes. Strain rates are moderate and interpass times are in the range of 5 to 20s. There is, therefore, as it can be seen from the description just made of the rolling schedule, a fair resemblance to deformation in plate mills. Technology for themomechanical processing, TMP, of plates is very well known and disseminated. Application of this technology to beam rolling is, on the other hand, rather seldom known of. This paper addresses an application of TMP plate technology to beam rolling. In particular, austenite grain size evolution is examined. The usage of Nb microalloyed steels to this process is discussed in terms of possible beneficial effects to ferrite grain refinement.

An Integrated Model for Rolling Schedule Design of Microalloyed Steels

2018 ◽  
Vol 941 ◽  
pp. 77-82
Author(s):  
Zhan Li Guo ◽  
Nigel Saunders ◽  
Jean Philippe Schillé
Keyword(s):  
Grain Size ◽  
Hot Rolling ◽  
Effective Strain ◽  
Deformation Resistance ◽  
Precipitate Size ◽  
Microalloyed Steels ◽  
Clear Understanding ◽  
Austenite Decomposition ◽  
Rolling Schedule ◽  
Wide Range

Processing parameters have direct impacts on the quality of the steels produced. This is particularly true for microalloyed steels, the production of which involves a thermomechanical controlled rolling process, which combines multi-pass hot rolling with accelerated cooling. On one hand, hot rolling may finish below A3temperature when austenite starts to transform to ferrite. On the other hand, controlled cooling is applied to obtain the desired microstructure from austenite decomposition. To optimise the TMCP parameters of such alloys, not only a clear understanding of each metallurgical phenomenon involved is required, but also the interactions among them. This paper reports our recent work on modelling of microstructural evolution and deformation resistance during multi-pass hot rolling of steels. The model considers the following metallurgical phenomena as well as their interactions: - Precipitation of MX type carbides, nitrides or carbonitrides. - Interactions between precipitation and recrystallisation and their effects on grain refinement. - Effect of grain size and cooling path on transformations from austenite to ferrite, pearlite, bainite and martensite. - Effect of rolling parameters, recrystallisation and microstructure on the deformation resistance of the alloy. The model predicts the evolution of microstructural features such as precipitate size and amount, recrystallisation fraction and effective strain, grain size, and austenite decomposition, as well as the alloy’s deformation resistance during hot rolling. It has been applied to a wide range of steels and demonstrated good agreement with experimental observations. Therefore, it has the great potential to be implemented in a production line to help optimise the rolling schedule for both C-Mn and microalloyed steels.

Research on Aluminum Plate Reversible Hot-Rolling Mathematical Model and Schedule

2012 ◽  
Vol 157-158 ◽  
pp. 719-726
Author(s):  
Hai Xiong Wang ◽  
Ji Bin Li ◽  
Hai Jun Liu ◽  
Chang Sheng Wang
Keyword(s):  
Mathematical Models ◽  
Hot Rolling ◽  
Rolling Process ◽  
Production Quality ◽  
Aluminum Plate ◽  
Test Results ◽  
Rolling Schedule ◽  
Schedule Optimization ◽  
Plate Rolling ◽  
Rolling Production

In order to carry out automatic transformation to the two-roll reversible hot-rolling mill of a aluminum plate production factory, firstly a series of mathematical models of aluminum plate hot-rolling parameters are established, then a new optimization algorithm which is suitable for aluminum plate rolling production combined with the various constraints in the rolling process is proposed, and rolling schedule optimization software system is developed. Finally, by measuring the process parameters in rolling production site and applying the optimized rolling schedule to the rolling production, many test data are obtained. The analysis of test results and evaluation of the practical production show that the mathematical models established have high accuracy compared with the old rolling schedule. The optimization schedule can not only ensure the production quality, but also has higher efficiency and less energy consumption.

The Influence of Initial Grain Size and Strain Sequence of Slab Hot Rolling on the Austenite Evolution of Peritectic Microalloyed Plate Steels

2014 ◽  
Vol 1019 ◽  
pp. 339-346 ◽  
Author(s):  
Rorisang Maubane ◽  
Kevin Banks ◽  
Waldo Stumpf ◽  
Charles Siyasiya ◽  
Alison Tuling
Keyword(s):  
Grain Size ◽  
Hot Rolling ◽  
Plain Carbon Steel ◽  
Microalloyed Steels ◽  
Heating Rates ◽  
Austenite Grain Size ◽  
Soaking Time ◽  
Austenite Grain ◽  
Dynamic Recrystallisation ◽  
Temperature Constant

The influence of the strain sequence during slab hot rolling (also known as “roughing”) on the evolution of austenite in plain carbon, C-Mn-V and C-Mn-Nb-Ti-V steels was investigated. Reheating and roughing simulations were conducted in a Bähr deformation dilatometer using a constant austenitising temperature, constant soaking time and various heating rates and roughing strain sequences. Stress analysis was used to quantify the austenite softening behaviour and the prior austenite grain size was measured from quenched specimens. The austenite grains of the plain carbon steel were coarser than those of both microalloyed steels, with the C-Mn-Nb-Ti-V grade being the finest due to effective pinning of the grain boundaries. Pass strains greater than 0.2 were sufficient for initiation of dynamic recrystallisation (DRX) for the C-Mn and C-Mn-V steels and led to uniform austenite microstructure with austenite grain sizes less than 40µm after the roughing stage.

Recrystallisation driving forces against pinning forces in hot rolling of Ti-microalloyed steels

2006 ◽  
Vol 423 (1-2) ◽  
pp. 253-261 ◽  
Author(s):  
M.I. Vega ◽  
S.F. Medina ◽  
A. Quispe ◽  
M. Gómez ◽  
P.P. Gómez
Keyword(s):  
Hot Rolling ◽  
Driving Forces ◽  
Microalloyed Steels

scholarly journals Study of the Microstructure and Strain Induced Precipitation during Thermomechanical Processing of Low Carbon Microalloyed Steels

2012 ◽  
Vol 706-709 ◽  
pp. 2118-2123
Author(s):  
Manuel Gómez ◽  
Pilar Valles ◽  
Sebastián F. Medina
Keyword(s):  
Hot Rolling ◽  
Thermomechanical Processing ◽  
High Strength ◽  
Transformation Products ◽  
Carbon Steels ◽  
Microalloyed Steels ◽  
Low Carbon ◽  
Mean Flow ◽  
Wide Range ◽  
Final Microstructure

A series of anisothermal multipass hot torsion tests were carried out to simulate hot rolling on three high-strength low-carbon steels with different amounts of Mn, Mo, Nb and Ti and designed for pipeline construction. Mean Flow Stress was graphically represented against the inverse of temperature to characterize the evolution of austenite microstructure during rolling. The effect of austenite strengthening obtained at the end of thermomechanical processing on the final microstructure obtained after cooling was studied. Higher levels of austenite strengthening before cooling promote a refinement of final microstructure but can also restrict the fraction of low-temperature transformation products such as acicular ferrite. This combined effect gives rise to a wide range of final microstructures and mechanical properties depending on the composition, processing schedule and cooling rates applied. On the other hand, the precipitation state obtained at diverse temperatures during and at the end of hot rolling schedule was evaluated by means of transmission electron microscopy (TEM) in two microalloyed steels. It was found that two families of precipitates with different morphology, composition and mean size can coexist in microalloyed steels.

scholarly journals Softening and Flow Stress Behaviour of Nb Microalloyed Steels during Hot Rolling Simulation.

1995 ◽  
Vol 35 (12) ◽  
pp. 1523-1531 ◽  
Author(s):  
L. Pentti Karjalainen ◽  
Terrence M. Maccagno ◽  
John J. Jonas
Keyword(s):  
Flow Stress ◽  
Hot Rolling ◽  
Microalloyed Steels ◽  
Stress Behaviour

scholarly journals Improvement of the Method for Calculating the Metal Temperature Loss on a Coilbox Unit at The Rolling on Hot Strip Mills

2018 ◽  
Vol 7 (4.3) ◽  
pp. 35 ◽  
Author(s):  
Volodymyr Kukhar ◽  
Oleksandr Kurpe ◽  
Eduard Klimov ◽  
Elena Balalayeva ◽  
Vladimir Dragobetskii
Keyword(s):  
Hot Rolling ◽  
Control Process ◽  
Rolling Process ◽  
Metal Temperature ◽  
Microalloyed Steels ◽  
Simulation Accuracy ◽  
Hot Strip ◽  
Temperature Loss ◽  
Hot Strip Mills ◽  
Improved Model

The paper improves the calculation methodology of metal temperature loss during hot rolling process at continuous mills. The proposed methodology can be implemented at hot strip mills with various in-line equipment arrangements within the temperature ranges appropriate for processes simulation of hot rolling, normalized rolling and Thermo-Mechanical Control Process of carbon and microalloyed steels. It provides engineering analysis of unaccounted temperature losses of feed by means of radiation and convection, which, in the first time, through the time factor, additionally accounts for strip motion speed factors, roller table length and feed length, and also length of rolls contact arc with metal. The accountability of the above mentioned factors in the various compositions depending on the rolling method increases the engineering simulation accuracy, ensures the versatility of the elaborated method with respect to different types of mills and makes the scientific novelty of the study. The equations were developed to calculate the metal temperature loss while coiling at the CoilBox unit. The equations accounts for the influence on the temperature of strip length, coiling and uncoiling speed, strip thickness, inside radius of the reeling coil, the time the feed rests being coiled. The improved model was verified based on actual data. 

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