Correlating Microstructural Features and Surface Roughening in Ferritic Stainless Steel

2007 ◽  
Vol 550 ◽  
pp. 65-74 ◽  
Author(s):  
R.D. Knutsen
Keyword(s):  
Stainless Steel ◽  
Ferritic Stainless Steel ◽  
Stainless Steels ◽  
Surface Roughening ◽  
Ferritic Stainless Steels ◽  
Transverse Strains ◽  
Different Levels

The surface ridging behaviour during tensile straining has been characterised for two ferritic stainless steels possessing different austenite potentials (0.1 and 0.6 respectively). Microstructural and texture heterogeneities have been detected to different levels in each steel and are used to explain the extent of surface ridging by considering a ridging mechanism arising from differential transverse strains. Orientation images are presented to trace the development of orientation clusters during recrystallisation.

scholarly journals CORROSION BEHAVIOUR OF AISI 460LI SUPER-FERRITIC STAINLESS STEEL

2019 ◽  
Vol 25 (4) ◽  
pp. 217
Author(s):  
Andrea Di Schino
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Ferritic Stainless Steel ◽  
Stainless Steels ◽  
Corrosion Behaviour ◽  
Ferritic Stainless Steels ◽  
Ferritic Alloys ◽  
Cr Content ◽  
Super Ferritic Stainless Steel ◽  
Steel Market

<p class="AMSmaintext1"><span lang="EN-GB">Following nickel and molybdenum significant price increase, nowadays the stainless steel market is moving toward an increasing use of ferritic stainless steel instead of austenitic stainless and therefore to the development of advanced ferritic stainless steels grades aimed to substitute the more expensive austenitic materials in all applications allowing it. Super-ferritic stainless steels are higher chromium (Cr) and molybdenum (Mo) steels with properties similar to those of standard ferritic alloys. Such elements increase high temperature and corrosion resistance in strong environment. This paper deal about the corrosion resistance of super-ferritic stainless steels with a Cr content ranging from 21% to 24%. </span></p>

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.

scholarly journals Austenitic-ferritic stainless steel containing niobium

2013 ◽  
Vol 66 (4) ◽  
pp. 467-471
Author(s):  
André Itman Filho ◽  
Wandercleiton da Silva Cardoso ◽  
Leonardo Cabral Gontijo ◽  
Rosana Vilarim da Silva ◽  
Luiz Carlos Casteletti
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Charge Transfer ◽  
Ferritic Stainless Steel ◽  
Stainless Steels ◽  
Sigma Phase ◽  
Charge Transfer Resistance ◽  
Chemical Compositions ◽  
Transfer Resistance ◽  
Ferritic Stainless Steels

The austenitic-ferritic stainless steels present a better combination of mechanical properties and stress corrosion resistance than the ferritic or austenitic ones. The microstructures of these steels depend on the chemical compositions and heat treatments. In these steels, solidification starts at about 1450ºC with the formation of ferrite, austenite at about 1300ºC and sigma phase in the range of 600 to 950ºC.The latter undertakes the corrosion resistance and the toughness of these steels. According to literature, niobium has a great influence in the transformation phase of austenitic-ferritic stainless steels. This study evaluated the effect of niobium in the microstructure, microhardness and charge transfer resistance of one austenitic-ferritic stainless steel. The samples were annealed at 1050ºC and aged at 850ºC to promote formation of the sigma phase. The corrosion testes were carried out in artificial saliva solution. The addition of 0.5% Nb in the steel led to the formation of the Laves phase.This phase, associated with the sigma phase, increases the hardness of the steel, although with a reduction in the values of the charge transfer resistance.

Effects of W on microstructure and high-temperature oxidation behavior of ferritic stainless steel weldment

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744042
Author(s):  
Yijie Ji ◽  
Yuye Xie ◽  
Shuangchun Zhu ◽  
Biao Yan
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Ferritic Stainless Steel ◽  
Stainless Steels ◽  
Oxidation Behavior ◽  
Surface Oxide Layer ◽  
Temperature Oxidation ◽  
Ferritic Stainless Steels ◽  
Steel Weldment ◽  
Stainless Steel Weldment

With the promotion of fuel economy policy and automobile lightweight concept, ferritic stainless steels applied in vehicles’ exhaust hot end systems have been developed. This paper simulated the high-temperature environment at which the automobile exhaust system serviced in for high-temperature corrosion. Kinetic curves were conducted in isothermal environments at 1000[Formula: see text]C. X-ray diffraction, scanning electron microscope and energy dispersive spectrometer were used to study the oxidation behavior of ferritic stainless steels and the effects of tungsten (W) addition. The results show that, with increasing oxidation time, the rate of weight gains increase and the main failure is spalling of surface oxide layer. The addition of W has a complicated effect on the oxidation behavior of ferritic stainless steel weldment.

High Temperature Characteristics of Lap Joint of 15Cr Ferritic Stainless Steel

2009 ◽  
Author(s):  
Younggi Lee ◽  
Gyeongcheol Lee ◽  
Jaeseong Kim ◽  
Boyoung Lee
Keyword(s):  
Tensile Strength ◽  
Stainless Steel ◽  
High Temperature ◽  
Tensile Test ◽  
Ferritic Stainless Steel ◽  
Stainless Steels ◽  
Heat Affected Zone ◽  
Lap Joint ◽  
Automotive Exhaust ◽  
Ferritic Stainless Steels

Ferritic stainless steels have excellent stress corrosion resistance and a low coefficient of thermal expansion compared to austenitic stainless steels. Ferritic stainless steels of the 400 series have been available for automotive exhaust systems, heat exchangers, radiators etc. in various industries. Automotive exhaust manifolds especially require good heat resistance because the typical operation temperature(800°C) of the exhaust system is exposed to during engine operation. In this study, the effects of high temperature(800°C) characteristics on the mechanical and microstructure properties were investigated for lap joint of ferritic stainless steel(STS 429) mainly used as the automotive exhaust manifolds. The microstructure of lap joint was characterized by optical microscopy(OM), scanning electron microscopy(SEM) and X-ray diffraction(XRD). The mechanical property of lap joint was evaluated by tensile test. The tensile test results show that a significant decrease in ultimate tensile strength(between 82 and 85%) was observed for aged STS 429 when tested at the evaluated temperature(800°C). The tensile strength was significantly influenced by growth of grain in the heat affected zone(HAZ). The XRD results show that chromium carbide and chromium nitride phases such as Cr23C6, Cr7C3, Cr2N and TiN were precipitated in the heat affected zone(HAZ).

scholarly journals New Ferritic Stainless Steel for Service Temperatures up to 1050 °C Utilizing Intermetallic Phase Transformation

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 664 ◽  
Author(s):  
Timo Juuti ◽  
Timo Manninen ◽  
Sampo Uusikallio ◽  
Jukka Kömi ◽  
David Porter
Keyword(s):  
Stainless Steel ◽  
Ferritic Stainless Steel ◽  
Stainless Steels ◽  
Creep Resistance ◽  
Volume Fraction ◽  
Intermetallic Phase ◽  
Precipitation Strengthening ◽  
Ferritic Stainless Steels ◽  
Thermodynamic Simulations ◽  
Grain Boundary Pinning

A large number of thermodynamic simulations has been used to design a new Nb-Ti dual stabilized ferritic stainless steel with excellent creep resistance at 1050 °C through an optimal volume fraction of Laves (η) phase stabilized by the alloying elements Nb, Si and Mo. By raising the dissolution temperature of the phase, which also corresponds to the onset of rapid grain growth, the steel will better maintain the mechanical properties at higher service temperature. Laves phase precipitates can also improve creep resistance through precipitation strengthening and grain boundary pinning depending on the dominant creep mechanism. Sag tests at high temperatures for the designed steel showed significantly better results compared to other ferritic stainless steels typically used in high temperature applications at present.

The Effect of Niobium Carbides and Laves Phase on the Yielding Behaviour of a Stabilized Ferritic Stainless Steel

2014 ◽  
Vol 783-786 ◽  
pp. 807-812 ◽  
Author(s):  
Timo J. Juuti ◽  
Timo Manninen ◽  
L. Pentti Karjalainen ◽  
David A. Porter
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Yield Point ◽  
Ferritic Stainless Steel ◽  
Stainless Steels ◽  
Laves Phase ◽  
Temper Rolling ◽  
Ferritic Stainless Steels ◽  
High Chromium ◽  
The Matrix

High-chromium ferritic stainless steels have been developed for applications such as exhaust systems that require good formability. To improve formability, continuous yielding is preferred. However, in high-chromium ferritic stainless steels an upper yield point is often present as a result of free interstitials and Cottrell atmospheres. The upper yield point can be removed by temper rolling but it would be better to avoid it via a suitable heat treatment. This paper describes how this can be done in the case of a ferritic stainless steel containing 0.011%C, 0.012%N, 18%Cr, 2,1%Mo, 0.33%Nb, 0.15Ti%. Despite the presence of Nb and Ti, which should bind the free carbon and nitrogen as carbides and nitrides, an upper yield point was still observed. Previously it has been suspected that this is due to an intermetallic Laves phase present in this steel depleting the Nb in the matrix so that some carbon remains free. A series of short-term annealing experiments showed that the upper yield point diminishes, when the annealing temperature increases above 550 °C, finally disappearing after a heat treatment at 750 °C. On the basis of Thermo-Calc calculations and EDS analyses, free interstitials in the matrix could be related to depletion of MX or insufficient time to reach the equilibrium state.

Corrosion of Ferritic Stainless Steel Weldments

2006 ◽  
pp. 77-97
Keyword(s):  
Stainless Steel ◽  
Ferritic Stainless Steel ◽  
Stainless Steels ◽  
Intergranular Corrosion ◽  
Crevice Corrosion ◽  
Cubic Crystal ◽  
Ferritic Stainless Steels ◽  
Chromium Alloys ◽  
Cause Of Failure ◽  
Primary Advantage

Abstract Ferritic stainless steels are essentially iron-chromium alloys with body-centered cubic crystal structures. Chromium content is usually in the range of 11 to 30%. The primary advantage of the ferritic stainless steels, and in particular the high-chromium, high-molybdenum grades, is their excellent stress-corrosion cracking resistance and good resistance to pitting and crevice corrosion in chloride environments. This chapter provides information on the classifications, properties, and general welding considerations of ferritic stainless steels. The emphasis is placed on intergranular corrosion, which is the most common cause of failure in ferritic stainless steel weldments. Two case histories involving intergranular corrosion failures of ferritic stainless steel weldments are included. A brief discussion on hydrogen embrittlement is also provided.

ARMCO 444

Alloy Digest ◽  
2000 ◽  
Vol 49 (7) ◽  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Physical Properties ◽  
Tensile Properties ◽  
Ferritic Stainless Steel ◽  
Stainless Steels ◽  
Crevice Corrosion ◽  
Low Carbon ◽  
Ferritic Stainless Steels ◽  
Low Nitrogen

Abstract Armco Type 444 is a low-carbon, low-nitrogen, ferritic stainless steel that provides pitting and crevice corrosion resistance superior to that of most ferritic stainless steels. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on corrosion resistance as well as forming and joining. Filing Code: SS-798. Producer or source: Armco Inc.

MAGIVAL MG2

Alloy Digest ◽  
2013 ◽  
Vol 62 (11) ◽  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Coercive Force ◽  
Magnetic Permeability ◽  
Stainless Steels ◽  
Heat Treating ◽  
Steel Grade ◽  
High Permeability ◽  
Ferritic Stainless Steels ◽  
Magnetic Applications

Abstract MAGIVAL MG2 is a free machining ferritic stainless steel grade with the same high machinability and corrosion resistance as type 430F, but offering a higher magnetic permeability and lower coercive force than MG1 (Alloy Digest SS-1159, October 2013). Magival is a group of easily workable ferritic stainless steels developed for magnetic applications where high permeability and low coercive force are required. This datasheet provides information on composition, physical properties, hardness, and elasticity. It also includes information on corrosion resistance as well as forming, heat treating, and joining. Filing Code: SS-1161. Producer or source: Valbruna Stainless Steel.

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