Precipitates and Lüders Elongation in Ferritic Stainless Steels Stabilized with Ti and V

2011 ◽  
Vol 194-196 ◽  
pp. 16-19 ◽  
Author(s):  
Fei Gao ◽  
Wei Na Zhang ◽  
Zhi Bo Zhang ◽  
Zhen Yu Liu ◽  
Guo Dong Wang
Keyword(s):  
Solid Solution ◽  
Internal Friction ◽  
Stainless Steels ◽  
Low Temperatures ◽  
Rolling Process ◽  
Ferritic Stainless Steels ◽  
Finish Rolling ◽  
Friction Measurements ◽  
Hot Rolled ◽  
Conventional Rolling

The influence of finish rolling temperature on the precipitates and Lüders elongation in ultra purified ferritic stainless steels stabilized with Ti and V has been investigated, in which the hot rolled bands were produced by conventional rolling process and the finish rolling at relatively low temperatures. It was shown that finish rolling at relatively low temperatures promoted the formation of a large number of fine MC precipitates, which were denser in dispersion and finer in size than those formed in conventional rolling process by strain-induced precipitation, and consequently scavenging of interstitial atoms in solid solution, indicating that the finish rolling at relatively low temperatures can be the effective way to significantly reduced Lüders elongation for the final sheets. These results have been confirmed by the internal friction measurements.

scholarly journals Defect Reduction in Ferritic Stainless Steels through Modelling Plastic Deformation and Metallurgical Evolution

2021 ◽  
Vol 3 (1) ◽  
pp. 22
Author(s):  
Silvia Mancini ◽  
Luigi Langellotto ◽  
Andrea Di Schino
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Microstructural Evolution ◽  
Stainless Steels ◽  
Hot Rolling ◽  
Hot Deformation ◽  
Rolling Process ◽  
Process Conditions ◽  
Ferritic Stainless Steels ◽  
Damage Models

Steel products made of ferritic steel can show some defects, such as jagged edges, following the hot rolling process. Aiming to identify the origin of this type of defect in order to help their reduction, an in-depth study has been carried out considering the hot rolling conditions of flat bars made of EN 1.4512 steel. A wide number of references to austenitic stainless steel can be found in literature: almost all the semi-empirical models describing the microstructural evolution during hot deformation refer to austenitic stainless steel. In this work, a comprehensive model for recrystallization and grain growth of the ferritic stainless steel grade EN 1.4512 is proposed, enriching the literature and works regarding ferritic stainless steels. Thermomechanical and metallurgical models have been implemented. The microstructural evolution and the damage of the material were calculated through the coupling of metallurgical and damage models. In the thermomechanical simulations of the roughing passes, three granulometry levels (PFGS) and three heating furnace temperatures were considered. The ferritic grain evolution metallurgical model was obtained by introducing apposite equations. The results highlight that the defect could be produced by process conditions that spark abnormal heating and consequently uncontrolled growth of the grains. The work-hardened grains undergo elongation during hot deformation without recrystallizing. Those grains “squeeze” the surrounding recrystallized grains towards the edges. Thus, on the edges occurs a series of cracks that macroscopically manifest themselves as jagged edges.

scholarly journals Defect Reduction and Quality Optimization by Modeling Plastic Deformation and Metallurgical Evolution in Ferritic Stainless Steels

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 186 ◽  
Author(s):  
Silvia Mancini ◽  
Luigi Langellotto ◽  
Paolo Emilio Di Nunzio ◽  
Chiara Zitelli ◽  
Andrea Di Schino
Keyword(s):  
Grain Size ◽  
Stainless Steels ◽  
Point Of View ◽  
Defect Reduction ◽  
Ferritic Stainless Steels ◽  
Damage Models ◽  
Commercial Code ◽  
Squeeze Out ◽  
Edge Defects ◽  
Hot Rolled

Manufacturing of ferritic stainless steels flat bars is an important industrial topic and the steel 1.4512 is one of the most commonly used grades for producing this component. In this paper, the origin of some edge defects occurring during hot rolling of flat bars of this grade is analyzed and thermomechanical and microstructural calculations have been carried out to enhance the quality of the finished products by reducing the jagged borders defect on hot rolled bars. An accurate investigation has been carried out by analyzing the defects on the final product from both the macroscopic and microstructural point of view through the implementation of thermomechanical and metallurgical models in a finite element (FE) MSC Marc commercial code. Coupled metallurgical and damage models have been implemented to investigate the microstructural evolution of ferritic grain size and material damaging. Three levels of prior ferritic grain size (PFGS) and three furnace discharge temperatures have been considered in the thermo-mechanical simulations of the roughing passes. Rheological laws for modeling the evolution of ferritic grain have been modified to describe the specific cases simulated. Results have shown that the defect is caused by processing conditions that trigger an anomalous heating which, in turn, induces an uncontrolled grain growth on the edges. The work-hardened and elongated grains do not recrystallize during hot deformation. Consequently, they tend to squeeze out the surrounding softer and recrystallized matrix towards the edges of the bar where the fractures that characterizes the surface defect occur.

scholarly journals Reduce the Planar Anisotropy of AA6016 Aluminum Sheets by Texture and Microstructure Control

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1027
Author(s):  
Xiaoge Duan ◽  
Haitao Jiang ◽  
Zhenli Mi ◽  
Lei Cheng ◽  
Jiayi Wang
Keyword(s):  
Solution Treatment ◽  
Rolling Process ◽  
Alloy Sheet ◽  
Electron Back Scatter Diffraction ◽  
Grain Structure ◽  
X Ray Diffraction ◽  
Planar Anisotropy ◽  
Aluminum Sheets ◽  
Hot Rolled ◽  
Conventional Rolling

In order to produce a more isotropic Al-Mg-Si alloy sheet in the T4 temper, pre-annealed AA6016 hot rolled strips were cold rolled by conventional rolling, transverse rolling and an alternative rolling schedule. In this work, a weak and random texture was obtained in the alternative rolling sample, which was treated by solution treatment, as well as a fine and homogeneous recrystallized grain structure that reduced the earing percentage from 8.2% to 2.7%. An earing test was used to characterize the planar anisotropy of the AA6016 alloy. The crystallographic texture and microstructure of the AA6016 aluminum sheet were analyzed by X-ray diffraction and electron back scatter diffraction (EBSD) techniques. The earing percentage was reduced and eight-fold ears were produced in unidirectional rolled samples with strong β-fiber textures. Conversely, a higher earing percentage and four-fold ears were obtained for the alternative rolled sample, which was characterized by an appropriate combination of the Cube {001}<100> and stabilized BND {011}<3`22> [(φ1,¢,φ2) = (42°,45°,0°)] orientations. The main reason for the distinct earing profiles was the grain spatial distribution of textures formed during the cold rolling process. The dynamic recovery of the AA6016 alloy was promoted and both the nucleation and subsequent growth of the Cube orientation were suppressed by alternative rolling.

Diffusion of Nitrogen in Ti-13V-11Cr-3Al Alloys

2009 ◽  
Vol 283-286 ◽  
pp. 38-44 ◽  
Author(s):  
Carlos Roberto Grandini ◽  
Emerson Haruiti Kamimura ◽  
José Roberto Severino Martins ◽  
Hugo Ricardo Zschommler Sandim ◽  
Odila Florêncio
Keyword(s):  
Solid Solution ◽  
Internal Friction ◽  
Diffusion Coefficients ◽  
Crystalline Lattice ◽  
Mechanical Spectroscopy ◽  
Interstitial Concentration ◽  
Exponential Factors ◽  
Friction Measurements ◽  
Internal Friction Spectra ◽  
Interstitial Elements

Metals with a bcc crystalline structure such as Ti-13V-11Cr-3Al alloys have their physical properties significantly changed through the addition of interstitial elements such as oxygen and nitrogen. These metals can dissolve substantial amounts of interstitial elements forming solid solutions. Mechanical spectroscopy measurements constitute a powerful tool for studying interactions of these interstitial elements with other elements that make up the alloy. From these measurements, it is possible to obtain information regarding diffusion, interstitial concentration, interaction between interstitials, and other imperfections of the crystalline lattice. In this paper, Ti-13V-11Cr-3Al alloys with several amount of nitrogen, in a solid solution, were studied using mechanical spectroscopy (internal friction) measurements. The results presented complex internal friction spectra which were resolved in a series of constituent Debye peaks corresponding to different interactions and interstitial diffusion coefficients. Pre-exponential factors and activation energies were calculated for nitrogen in theses alloys.

NiAl precipitation in Fe-12w/o Cr-5w/o Ni-4w/o Al

1983 ◽  
Vol 41 ◽  
pp. 202-203
Author(s):  
L.E. Murr ◽  
J.S. Dunning ◽  
S. Shankar
Keyword(s):  
Solid Solution ◽  
Stainless Steel ◽  
Stainless Steels ◽  
Alloy Composition ◽  
Chromium Content ◽  
Scale Up ◽  
Optical Metallography ◽  
Property Evaluation ◽  
310 Stainless Steel ◽  
Microstructural Studies

Aluminum additions to conventional 18Cr-8Ni austenitic stainless steel compositions impart excellent resistance to high sulfur environments. However, problems are typically encountered with aluminum additions above about 1% due to embrittlement caused by aluminum in solid solution and the precipitation of NiAl. Consequently, little use has been made of aluminum alloy additions to stainless steels for use in sulfur or H2S environments in the chemical industry, energy conversion or generation, and mineral processing, for example.A research program at the Albany Research Center has concentrated on the development of a wrought alloy composition with as low a chromium content as possible, with the idea of developing a low-chromium substitute for 310 stainless steel (25Cr-20Ni) which is often used in high-sulfur environments. On the basis of workability and microstructural studies involving optical metallography on 100g button ingots soaked at 700°C and air-cooled, a low-alloy composition Fe-12Cr-5Ni-4Al (in wt %) was selected for scale up and property evaluation.

AN INTERNAL FRICTION STUDY OF N-H AND O-H PAIRS IN SINGLE CRYSTAL OF NIOBIUM AT LOW TEMPERATURES

1981 ◽  
Vol 42 (C5) ◽  
pp. C5-757-C5-761 ◽  
Author(s):  
R. Hanada ◽  
M. Shinohara ◽  
Y. Sado ◽  
H. Kimura
Keyword(s):  
Internal Friction ◽  
Single Crystal ◽  
Low Temperatures ◽  
Friction Study

INTERNAL FRICTION STUDIES ON HYDROGEN IN SOLID SOLUTION IN V-Nb ALLOYS

1985 ◽  
Vol 46 (C10) ◽  
pp. C10-107-C10-110
Author(s):  
C. V. OWEN ◽  
O. BUCK ◽  
R. R. SMITH ◽  
D. T. PETERSON
Keyword(s):  
Solid Solution ◽  
Internal Friction

STUDY OF THE Cu-Zn-Al MARTENSITE AGING BY INTERNAL FRICTION MEASUREMENTS

1987 ◽  
Vol 48 (C8) ◽  
pp. C8-567-C8-572
Author(s):  
M. MORIN ◽  
M. HAOURIKI ◽  
G. GUENIN
Keyword(s):  
Internal Friction ◽  
Friction Measurements

Microstructure and Friction of Ion Beam Induced Amorphous Ti-Pd Alloys

1985 ◽  
Vol 55 ◽  
Author(s):  
J-P. Hirvonen ◽  
M. Nastasi ◽  
J. R. Phillips ◽  
J. W. Mayer
Keyword(s):  
Solid Solution ◽  
Friction Coefficient ◽  
Composition Range ◽  
Ion Beam ◽  
Amorphous Region ◽  
Transmission Electron ◽  
Solid Solution Region ◽  
Friction Measurements ◽  
Solution Region ◽  
High Equilibrium

ABSTRACTMultilayered samples of Ti-Pd with linearly varying compositions were irradiated by Xe ions at 600 keV. The induced microstructures were studied by using transmission electron microscopy and Rutherford backscattering. Mixing was found to be complete over the entire composition range, resulting in amorphous or amorphous plus crystalline structures except at the palladium-rich end, where a crystalline Pd-Ti solid solution was obtained. This is consistent with the high equilibrium solubility of Ti in Pd. In addition, significant coarsening of the microstructure caused by irradiation was found in this solid solution region.Friction measurements were carried out in air and water by using a polytetrafluoroethylene pin as a counterpart. In air the friction coefficient was independent of composition and microstructure after about 2000 passes. In water, however, after 600 passes the friction coefficient reached a steady-state value with a pronounced minimum over the amorphous region. This property was unchanged throughout the remaining 10000 passes.

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