Recrystallization of Coarse-Grained Nb-Containing AISI-430 Ferritic Stainless Steel

2010 ◽  
Vol 638-642 ◽  
pp. 3009-3014 ◽  
Author(s):  
Rodrigo P. Siqueira ◽  
Hugo Ricardo Zschommler Sandim ◽  
Tarcisio R. Oliveira
Keyword(s):  
Stainless Steel ◽  
Ferritic Stainless Steel ◽  
Electron Backscatter Diffraction ◽  
Secondary Recrystallization ◽  
Coarse Grained ◽  
Ferritic Stainless Steels ◽  
Coarse Grains ◽  
Cold Rolled ◽  
Backscatter Diffraction ◽  
Aisi 430

Ferritic stainless steels (FSSs) have excellent corrosion resistance and good mechanical properties. Applications include heaters, houseware, and automotive exhaust systems. Alloying, even in small amounts, affects the recrystallization behavior of FSSs by selective dragging or pinning effects. In the present study, we present the main results regarding the recrystallization of a coarse-grained Nb-containing AISI 430 ferritic stainless steel. The material was processed by hot rolling and further annealed at 1250oC for 2 h to promote secondary recrystallization. Following, the material was cold rolled to a 80% reduction in thickness and annealed at 400-1000oC for 15 min. Scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) were used to characterize the microstructure. Recrystallization of this steel begins at 700oC. Important orientation effects were observed in both as-rolled and annealed conditions. Recrystallization kinetics was strongly dependent on the initial orientation of the coarse grains. Results show that grain boundaries, transition bands and coarse Nb(C,N) particles are preferential sites for nucleation at moderate annealing temperatures.

Grains and Sub Grains Identification in AISI 430 Stainless Steel with Atomic and Magnetic Force Microscopies

2005 ◽  
Vol 11 (S03) ◽  
pp. 150-153 ◽  
Author(s):  
J. M. C. Vilela ◽  
N. J. L. de Oliveira ◽  
M. L. Talarico ◽  
M. S. Andrade ◽  
R. A. N. M. Barbosa ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Ferritic Stainless Steel ◽  
Magnetic Force ◽  
Electron Backscatter Diffraction ◽  
Polarized Light ◽  
Force Microscopy ◽  
430 Stainless Steel ◽  
Anisotropic Plastic ◽  
Backscatter Diffraction ◽  
Aisi 430

Cold rolled sheets of AISI 430 ferritic stainless steel have been widely used in kitchen utensils, ornamental articles, among other products due to their corrosion resistance and good formability. However, a localized increase of the surface roughness, known as ridging, develops during ferritic stainless steel forming [1]. The ridging is caused by anisotropic plastic flow of the material containing alternated bands of different crystallographic textures. These bands, or grain colonies, are formed during hot rolling fabrication step. During this step, the deformed grains can undergo dynamic recrystallization and/or recovery. In the regions where recovery takes place these texture bands are formed. In order to study ridging, it is necessary to identify the recovered regions (regions containing sub grains with nearly the same crystal orientation) and recrystallized regions (regions containing grains with different crystal orientations). Two well established techniques are applied to the characterization of recrystallized and recovered grains: the optical microscopy with polarized light, normally done in samples prepared with colored etching, and the electron backscatter diffraction (EBSD). In this work, atomic force microscopy (AFM) and magnetic force microscopy (MFM) were used to study the recrystallization and the recovery of the deformed specimens.

scholarly journals Mechanical Properties and Hydrogen Embrittlement of Laser-Surface Melted AISI 430 Ferritic Stainless Steel

Coatings ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 140 ◽  
Author(s):  
W. K. Chan ◽  
C. T. Kwok ◽  
K. H. Lo
Keyword(s):  
Stainless Steel ◽  
Hydrogen Embrittlement ◽  
Strain Rate ◽  
Ferritic Stainless Steel ◽  
Laser Scanning ◽  
Electron Backscatter Diffraction ◽  
Microstructural Analysis ◽  
Scanning Speed ◽  
Laser Surface ◽  
Aisi 430

In the present study, the feasibility of laser surface melting (LSM) of AISI 430 ferritic stainless steel to minimize hydrogen embrittlement (HE) was investigated. LSM of AISI 430 steel was successfully achieved by a 2.3-kW high power diode laser (HPDL) with scanning speeds of 60 mm/s and 80 mm/s (the samples are designated as V60 and V80, respectively) at a power of 2 kW. To investigate the HE effect on the AISI 430 steel without and with LSM, hydrogen was introduced into specimens by cathodic charging in 0.1 M NaOH solution under galvanostatic conditions at a current density of 30 mA/cm2 and 25 °C. Detail microstructural analysis was performed and the correlation of microstructure with HE was evaluated. By electron backscatter diffraction (EBSD) analysis, the austenite contents for the laser-surface melted specimens V60 and V80 are found to be 0.6 and 1.9 wt%, respectively. The amount of retained austenite in LSM specimens was reduced with lower laser scanning speed. The surface microhardness of the laser-surface melted AISI 430 steel (~280 HV0.2) is found to be increased by 56% as compared with that of the substrate (~180 HV0.2) because of the presence of martensite. The degree of embrittlement caused by hydrogen for the charged and non-charged AISI 430 steel was obtained using slow-strain-rate tensile (SSRT) test in air at a strain rate of 3 × 10−5 s−1. After hydrogen pre-charging, the ductility of as-received AISI 430 steel was reduced from 0.44 to 0.25 while the laser-surface melted AISI 430 steel showed similar tensile properties as the as-received one. After LSM, the value of HE susceptibility Iδ decreases from 43.2% to 38.9% and 38.2% for V60 and V80, respectively, due to the presence of martensite.

The Effect of Heating Rate and Temperature on Microstructure and R-Value of Type 430 Ferritic Stainless Steel

2018 ◽  
Vol 941 ◽  
pp. 364-369
Author(s):  
Matias Jaskari ◽  
Antti Järvenpää ◽  
L. Pentti Karjalainen
Keyword(s):  
Grain Size ◽  
Stainless Steel ◽  
Heating Rate ◽  
Ferritic Stainless Steel ◽  
Stainless Steels ◽  
High Heating Rate ◽  
Rolled Sheet ◽  
Ferritic Stainless Steels ◽  
Cold Rolled ◽  
R Value

Typical applications of ferritic stainless steels require good formability of a steel that is highly dependent on the processing route. In this study, the effects of heating rate and peak temperature on the texture and formability of a 78% cold-rolled unstabilized 17%Cr (AISI 430) ferritic stainless steel were studied. The cold-rolled sheet pieces were heated in a Gleeble 3800 simulator at the heating rates of 25 °C/s and 500 °C/s up to various peak temperatures below 950 °C for 10 s holding before the final cooling at 35 °C/s to room temperature. Microstructures were characterized and the texture of the annealed samples determined by the electron backscatter diffraction method. The R-value in various directions was determined by tensile straining to 15%. It was established that the high heating rate of 500 °C/s tends to promote the nucleation of grains with the {111}<uvw> orientations during the early state of the recrystallization. The higher heating rate led to a slightly finer grain size and to a marginal improvement in the intensity of the gamma-fibre texture. A coarser grain size would be beneficial for the formability, but the grain growth was suppressed due to low peak temperatures and a short soaking time. Anyhow, the fast annealing resulted in an enhanced R-value in the transverse to rolling direction. The results indicate that even a short annealing cycle is plausible for producing ferritic stainless steels with the formability properties comparable to those of commercial counterparts.

Characters of Coarse Grains Subdivisions in Rolled Polycrystalline Al

2007 ◽  
Vol 546-549 ◽  
pp. 1033-1036
Author(s):  
Qi Ping Hu ◽  
Yong Zhang ◽  
Yun Lai Deng
Keyword(s):  
High Purity ◽  
Electron Backscatter Diffraction ◽  
Coarse Grains ◽  
Electron Backscatter ◽  
Columnar Grains ◽  
Cold Rolled ◽  
Ebsd Technique ◽  
The Individual ◽  
Individual Grains ◽  
Backscatter Diffraction

Deformation microstructures and micro-orientations of columnar grains with different orientations in a polycrystalline high purity Al cold-rolled up to 65% (thickness reduction) were investigated using electron backscatter diffraction (EBSD) technique. It was found that rotations were Inhomogeneous within the individual grains, the rotation angles of the parts close to the initial boundaries (BPs) were smaller than those remote from the boundaries (IPs), e.g. the deviation angles between the BPs and the IPs were 5-6° in the grains with <001>//RD orientation, leading to the rotation along the α-fiber, while the deviation angles were 5-12° in the grains with <121>//ND orientation rotating toward the β-fiber. These results demonstrated that the microstructures and local rotations of various parts within the rolled individual columnar grains were influenced by their initial orientations and boundaries.

Recovery and Recrystallization as a Function of Deformed Microstructure Orientation in Coarse Grained Cold-Rolled Ni

2007 ◽  
Vol 558-559 ◽  
pp. 149-152
Author(s):  
H.S. Chen ◽  
Andrew Godfrey ◽  
Niels Hansen ◽  
Qing Liu
Keyword(s):  
Grain Size ◽  
Crystal Orientation ◽  
Electron Backscatter Diffraction ◽  
Rolling Texture ◽  
Coarse Grained ◽  
Localized Deformation ◽  
Orientation Mapping ◽  
Average Grain Size ◽  
Cold Rolled ◽  
Backscatter Diffraction

The effect of crystal orientation on the recovery and recrystallization of cold-rolled Ni (99.96% purity) has been investigated. Particular attention was paid to the annealing response of regions with either the Copper (C), Brass (B) or S rolling texture orientations. Samples with an initial average grain size of approx. 500μm were deformed to strains of up to εvM = 4.5. As a result of the large initial grain size, even after high rolling reductions it is possible to find sufficiently large regions of material with similar crystal orientation to analyze the recovery and recrystallization behaviour as a function of crystal orientation. Microstructural investigations were carried out in the scanning electron microscope using both electron channeling contrast and electron backscatter diffraction orientation mapping. Both the S and C orientation regions exhibit a heterogeneous microstructure containing bands of localized deformation. The presence of volumes surrounded by high angle boundaries in these regions strongly influences both the recovery and recrystallization behaviour of the material. Twinning was observed also to play an important role in the generation of recrystallized grains, with twin chains of up to 3 generations being observed.

Analysis of Chemical Changes and Microstructure Characterization during Deformation in Ferritic Stainless Steel

2013 ◽  
Vol 19 (4) ◽  
pp. 959-968 ◽  
Author(s):  
Andrés Núñez ◽  
Xavier Llovet ◽  
Juan F. Almagro
Keyword(s):  
Stainless Steel ◽  
Ferritic Stainless Steel ◽  
Electron Backscatter Diffraction ◽  
Biaxial Tension ◽  
Annealing Treatment ◽  
Chemical Compositions ◽  
Backscatter Electron Imaging ◽  
Electron Imaging ◽  
Deformation Tests ◽  
Backscatter Diffraction

AbstractUni- and biaxial tension deformation tests, with different degrees of deformation, have been done on AISI 430 (EN 1.4016) ferritic stainless steel samples, which had both different chemical compositions and had undergone different annealing treatments. The initial and deformed materials were characterized by using electron backscatter diffraction and backscatter electron imaging in a scanning electron microscope together with electron probe microanalysis. The correlation observed among the chemical compositions, annealing treatment, and strain level obtained after deformation is discussed.

Effect of Hot Deformation Temperature on the Restoration Mechanisms and Texture in a High-Cr Ferritic Stainless Steel

2013 ◽  
Vol 762 ◽  
pp. 705-710 ◽  
Author(s):  
Saara Mehtonen ◽  
L. Pentti Karjalainen ◽  
David A. Porter
Keyword(s):  
Stainless Steel ◽  
Ferritic Stainless Steel ◽  
Hot Deformation ◽  
Deformation Temperature ◽  
Electron Backscatter Diffraction ◽  
Shear Bands ◽  
Compression Tests ◽  
Recrystallized Grain Size ◽  
Evolution Of Microstructure ◽  
Backscatter Diffraction

The effect of hot deformation temperature on the deformed microstructures and evolution of microstructure and texture of a 21Cr Ti-Nb dual-stabilized ferritic stainless steel was studied using plane strain hot compression tests on a Gleeble 1500 thermomechanical simulator. The deformation was carried out at 550 - 950 °C with a strain of 0.5 at 1 s-1. The compression was followed by fast cooling to room temperature in order to study the deformed microstructures. Some specimens were heated from the deformation stage to either 750 or 950 °C and held for 0 or 30 s in order to study the nucleation process of recrystallization. The electron backscatter diffraction technique was used to analyze the resultant microstructures and textures. Lowering of the deformation temperature increased the rate of static recrystallization (SRX) and decreased the recrystallized grain size. After deformation at 550 and 600 °C and complete SRX, beneficial γ-fibre texture formed presumably as a result of nucleation at in-grain shear bands. SRX after deformation at 750 °C or above led to the formation of harmful α-fibre textures with weak γ-fibre.

Texture Evolution of Ferritic (AlSl 430) Stainless Steel Strips during Cold Rolling, Annealing and Drawing

2007 ◽  
Vol 539-543 ◽  
pp. 4926-4931 ◽  
Author(s):  
A. Ferreira Filho ◽  
C. Herrera ◽  
Nelson Batista de Lima ◽  
R.L. Plaut ◽  
Angelo Fernando Padilha
Keyword(s):  
Stainless Steel ◽  
Cold Rolling ◽  
Stainless Steels ◽  
Deep Drawing ◽  
Texture Evolution ◽  
Steel Mill ◽  
Ferritic Stainless Steels ◽  
430 Stainless Steel ◽  
Cold Rolled ◽  
Aisi 430

The evolution of the crystallographic texture of ferritic stainless steels, starting from the as received (hot rolled) condition from the steel mill, going through cold rolling, annealing and final stamping is analyzed in this paper. Two ferritic stainless steels (Nb stabilized) having a thickness of 3.0 and 0.7mm, have been employed. The thicker one has been cold rolled to 40 and 73% thickness reduction, annealed at 750 and 850°C for 1 hour. The thinner one, with a similar composition, has been 77% cold rolled and annealed at 870°C at the steel plant and subsequently submitted to deep drawing in order to evaluate texture and drawability. Texture has been evaluated using DRX in the as received, cold rolled, annealed and after drawing conditions. Drawability has been evaluated using tensile testing in order to obtain the FLC curves. AISI 430 stainless steel, in the as received condition presented a strong {100} texture in the <110> and <120> directions and the gamma fiber. After cold rolling, the material presented stronger gamma and weaker alpha fibers. Annealing of the cold rolled samples conduced to the vanishing of the alpha and strengthening of the gamma fiber, adequate for deep drawing operations. In spite of the AISI 430 of 0.7mm having presented a strong gamma fiber, other deep drawing properties were not adequate and the material cracked during stamping.

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