Precipitation Behavior of Warm-Rolled Ti-Stabilized Interstitial-Free (IF) Steel Sheets

2007 ◽  
Vol 353-358 ◽  
pp. 1653-1656 ◽  
Author(s):  
Fu Tao Han ◽  
Zuo Cheng Wang ◽  
Cai Nian Jing ◽  
Wen Ping Zhang

Precipitates have great influence on the recrystallization, texture evolution and thus the final mechanical properties of the Interstitial-Free (IF) steel sheets, however, very few studies have dealt with the precipitation behavior of IF steels warm rolled in ferrite region. In the present work, the precipitate characteristics (type, morphology, size and amount) of warm-rolled ordinary Ti-stabilized Interstitial-Free (Ti-IF) steel and p-added high-strength Ti-IF steel were investigated by Transmission Electron Microscope (TEM) and Energy Dispersion Spectrometer (EDS). The results show that most precipitates in warm-rolled ordinary Ti-IF steels are TiN, TiS, Ti4C2S2 and TiC. Besides these precipitates, a great amount of FeTiP precipitates exist in warm-rolled P-added high-strength Ti-IF steel. The precipitation of FeTiP retards the migration of grain boundary in the recrystallization annealing, so the {111} texture and thus deep drawability of warm-rolled high-strength Ti-IF steel is deteriorated.

2010 ◽  
Vol 97-101 ◽  
pp. 416-419 ◽  
Author(s):  
Wei Min Guo ◽  
Zuo Cheng Wang ◽  
Sheng Liu ◽  
Li Bin Song

High-strength IF steel sheet has increasingly attracted more attention of steelmakers in recent years as it has the potential to lighten the weight of automobiles and save energy and lower the production cost. In this paper, the effect of processing parameters on microstructures and mechanical properties especially deep drawability of ferritic-rolled P-added high strength Ti-stabilized IF steels were investigated and the precipitates in the steels were also analyzed. The results show that lubricant condition has great influence on the r-value and deep drawability of high-strength IF steels. And with the decrease of rolling temperature in ferrite region, the deep drawability of steels is improved.


2006 ◽  
Vol 326-328 ◽  
pp. 1291-1294 ◽  
Author(s):  
Cai Nian Jing ◽  
Zuo Cheng Wang ◽  
Fu Tao Han ◽  
Wen Ping Zhang ◽  
Yan Hong Yi

Warm-rolling can save the production cost and extend the production kind of hot-rolled IF steel strip, the precipitates strongly influence the annealing process and texture evolution so as to the final mechanical properties of the production, very few studies has relate to the precipitates of IF steels warm-rolled in ferrite region. In present work, two Ti- IF steels were warm-rolled in ferrite region under different rolling parameters and the precipitates were investigated. Transmission electron microscopy (TEM) and Energy dispersion Spectroscopy (EDS) microanalysis were carried out on carbon extraction replicas, the characteristics such as morphology, type, amount and size of precipitates were analyzed. The results show that different type of precipitates were appeared in two steels, TiN, TiS, Ti4C2S2 and TiC were found in common Ti-IF steel, but in high strength Ti-IF steel, the amount of TiS, Ti4C2S2 was very few and FeTiP precipitates appeared, the type and morphology of precipitates were not affected by rolling parameters, however, the number and size of precipitates were changed. Finally, the effect of different P content on the change of precipitates was analyzed, the precipitating mechanism was also discussed.


2010 ◽  
Vol 638-642 ◽  
pp. 2781-2786
Author(s):  
Chang Shu He ◽  
Sadahiro Tsurekawa ◽  
Hiroyuki Kokawa ◽  
Xiang Zhao ◽  
Liang Zuo

An AC magnetic field (0.5Tesla) is applied with the field direction perpendicular to the rolling direction during annealing of a 76% cold-rolled IF steel sheet. Microstructure and texture evolution in the as-annealed specimens were determined using SEM based OIM technique. It is found that the recrystallization is noticeably retarded by AC magnetic field annealing. At the early stage of recrystallization (annealing at 650°C for 30min), the development of (111) <123> orientations was favored by the AC magnetic field. With progress of recrystallization (annealing at 700°C and 750°C for 30min), the applied AC magnetic field suppressed the development of γ-fiber recrystallization textures to some extent.


2005 ◽  
Vol 495-497 ◽  
pp. 411-416
Author(s):  
Y.X. Cai ◽  
Y.D. Liu ◽  
Yi Nong Wang ◽  
Gang Wang ◽  
Yan Dong Wang ◽  
...  

The aim of this work is to investigate the relationship between the deformation microstructure and texture in cold rolled Interstitial Free (IF) steel sheets. In the present research, the cold rolled IF steel sheets with 10%-50% reductions are used to observe the characteristic microstructure and individual orientations by transmission electron microscopy (TEM) and SAED patterns. The experimental results on inter-granular strain homogeneity and dislocation wall formation are given in details in this paper. The results are explained by the analysis of crystallographic gliding and are helpful to improve the prediction of cold rolling textures.


2011 ◽  
Vol 702-703 ◽  
pp. 123-126
Author(s):  
Onur Saray ◽  
Gencaga Purcek ◽  
B. Mahato ◽  
Sandip Ghosh Chowdhury

Interstitial-Free steel (IF-steel) sheets were severe plastically deformed using a continuous equal-channel angular extrusion/pressing technique called “Equal-Channel Angular Sheet Extrusion (ECASE). After processing, texture development as well as microstructural alteration and tensile properties were investigated. The microstructural investigations revealed that the processed sheets exhibited a dislocation cell and/or subgrain structures with mostly low angle grain boundaries. It was also observed that the strength of the processed sheets increased substantially after ECASE processing in the expense of ductility. It was shown that the ECASE has moderate influence on the texture of IF-steel sheets through route A. Intially there was θ partial fiber which changes to {110}θ with straining.


2011 ◽  
Vol 682 ◽  
pp. 71-74
Author(s):  
Cai Nian Jing ◽  
Ming Gang Wang ◽  
Xi Jun Liu ◽  
Qi Zhong Tan ◽  
Zuo Cheng Wang ◽  
...  

Interstitial-free (IF) steel has excellent deep-drawability and was used widely in automotive industry. High strength IF-steel is that some phosphorus was put in common IF-steel to improve its strength without destroying the deep-drawability [1]. Microstructure and grain boundary character strongly affect the deep-drawability of high strength IF-steel, it is an obligatory task to test those characters. The technique of Electron Backscatter Diffraction (EBSD) can reveal the microtexture and detailed orientation distribution of grains from a single EBSD map, as a powerful instrument, EBSD was used widely in materials research from last decade [2]. Many researches have been focused on the texture evolution and recrystallization phenomena of high strength IF-steels [3,4], but the microtexture and grain boundary characters of warm-rolled high strength IF-steels was not fully investigated. The present study was aimed at researching the microtexture characters of a commercial high strength IF-steels under different warm-rolled temperature using EBSD technique, the microstructure and grain boundary character were analyzed systemically, and the relationship between the microstructure and deep-drawability was discussed.


Metals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 288 ◽  
Author(s):  
Anmin Yin ◽  
Xiaodong Xu ◽  
Shuyi Zhang ◽  
Christ Glorieux ◽  
Xuedao Shu ◽  
...  

The analyses of texture evolution of cold rolled interstitial free (IF) steel sheets during annealing and recrystallization are presented, in which the dispersion curves of surface acoustic waves (SAW) excited by laser-induced transient thermal grating method are measured. The results show that the angular anisotropy of the SAW velocity changes due to the texture changes at different stages of recrystallization. The theoretically simulated angular dispersion of SAW velocity within individual crystal revealed that the change of SAW velocity is closely related to recrystallization texture evolution. A model for the angular dependence of the SAW velocity in textured polycrystalline IF steel with different oriented crystals is presented and the simulations are yielded, which show that the results agree with those of experiments.


2013 ◽  
Vol 753 ◽  
pp. 169-172
Author(s):  
Juan Jia ◽  
Wei Wei Zhu ◽  
Heng Gao ◽  
Li Bin Dai ◽  
Meng Li ◽  
...  

One kind of high strength interstitial free steel sheets are annealed in a salt bath at 810 C for different times (1-30 s). The microstructure and recrystallized texture evolution during annealing are investigated using the optical microscopy and the Electron Back Scattered Diffraction technique. The results show that beginning and finishing of recrystallization are observed in the sample annealed at 810 C for 8 and for 20 s, respectively. The recrystallized grains nucleate in the order of ‹111›//ND, ‹110›//ND and ‹100›//ND. Recrystallized grains with ‹111›//ND orientation nucleate firstly in the ‹111›//ND deformed grains as well as at their boundaries and grow up by consuming the ‹111›//ND deformed grains at the initial stage of recrystallization. The ‹111›//ND recrystallized grains grow up by depleting the remained formed ‹100›//ND grains after the full consumption of the ‹111›//ND deformed grains. The overall recrystallization texture is mainly the ‹111›//ND component in the steel.


2015 ◽  
Vol 1120-1121 ◽  
pp. 1003-1007 ◽  
Author(s):  
He Long Cai ◽  
Jun Sheng Mou ◽  
Zi Yong Hou

In this paper, common continous annealing (CCA) and ultra-fast annealing (UFA) were carried out on a cold-rolled interstitial-free (IF) steel, respectively. The microstructure of the annealed IF steel was characterized by means of scanning electron microscopy (SEM), electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). The mechanical property was examined using tensile test. The optimum annealing process parameters were then obtained. The results showed that, the recrystallization occurs at the temperature in the range of 780-830°C. The fraction of equiaxed grain increases with the annealing temperature increasing. The well combination of mechanical properties and formability was obtained when the IF steel annealed at 820°C, which was the result of the fine dispersed second phase particles. {001} texture was absent in the whole thickness of all the annealed IF steels. In addition, the strongest γ texture was found, and this was a potential way to improve the deep drawability of annealed steel sheets.


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