scholarly journals Influence of Vanadium and Cast Temperature on Nitrogen Solubility of Stainless Steel

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Saeed Ghali
Keyword(s):  
Stainless Steel ◽  
Chemical Composition ◽  
Stainless Steels ◽  
Induction Furnace ◽  
Nitrogen Solubility ◽  
Vanadium Content ◽  
Steel Grades ◽  
Cr 5.17 ◽  
Open Induction ◽  
Nitrogen Contents

Three stainless steel grades with different vanadium content were produced in open induction furnace. The base chemical composition of investigated stainless steel has contained 18.48–18.75% Cr, 5.17–5.62% Mn, 2.47–2.58% Mo, and 6.39–6.64% Ni. The vanadium contents of the three stainless steel grades were 0.009%, 0.112%, and 0.189%. The proposed stainless steels were casted at temperatures 1753 K and 1833 K. The nitrogen contents were determined for the produced steel grades at every cast temperature. The determined nitrogen contents were compared with those calculated from the developed equation of Grigorenko and Pomarin. The influence of cast temperature and vanadium content on nitrogen solubility was investigated. Interpretation between experimental and calculated nitrogen content was carried out. Increasing vanadium content and decreasing cast temperature were found to have positive significant effect on the nitrogen solubility. There were great deviations between experimental results and those calculated by Grigorenko and Pomarin equation.

Characterization of Dissimilar Welded Joints Between Austenitic and Duplex Stainless Steel Grades for Liquid Tank Applications

2018 ◽  
Author(s):  
G. Ubertalli ◽  
M. Ferraris ◽  
P. Matteis ◽  
D. Di Saverio
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Stainless Steels ◽  
Welded Joints ◽  
Industrial Applications ◽  
Duplex Stainless Steels ◽  
Steel Pipes ◽  
Steel Grades ◽  
Welding Processes

Lean duplex stainless steels have similar corrosion and better mechanical properties than the austenitic grades, which ensure their extensive spreading in industrial applications as a substitute of austenitic grades. In the construction of liquid tanks, however, it is often necessary to weld such steels with a range of fittings which are commonly fabricated with austenitic stainless steel grades. Therefore, this paper examines dissimilar welded joints between LDX 2101 (or X2CrMnNiN22-5-2) lean duplex stainless steels plates and austenitic stainless steel pipes, carried out by different arc welding processes. The investigation focuses on the correlation between the welding procedures and the microstructural and mechanical properties of the welded joints.

Wear of Thermochemically Produced Nitrogen Stainless Steel

1986 ◽  
Vol 108 (3) ◽  
pp. 334-339 ◽  
Author(s):  
B. F. Campillo Illanes ◽  
A. D. Sarkar
Keyword(s):  
Stainless Steel ◽  
Nitrogen Content ◽  
Stainless Steels ◽  
Martensitic Steel ◽  
Hardened Layer ◽  
Interfacial Shear ◽  
High Carbon ◽  
Heavy Load ◽  
Nitrogen Contents ◽  
Carbon Martensitic Steel

Thermochemically produced stainless steels with varying nitrogen content were slid dry on high carbon martensitic steel counterfaces using a pin bush machine. The running-in wear was high but the steady state wear decreased with increased nitrogen contents of the steels. A work hardened layer formed on the pins, the degree of hardening increasing with the nitrogen content of the steels. The hard pins caused a considerable amount of wear of the bushes, possibly, by ploughing. The pins wore by transfer and oxidation and, by interfacial shear and, probably, brittle fracture of the work hardened layer at a heavy load.

scholarly journals Stainless steel corrosion in instrumentation pipe

2019 ◽  
Vol 14 (40) ◽  
pp. 31-40
Author(s):  
Jean Victal do Nascimento ◽  
Rafael Adão de Carvalho ◽  
Davi Pereira Garcia ◽  
Rômulo Maziero ◽  
Edelize Angelica Gomes ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Chemical Composition ◽  
Austenitic Stainless Steel ◽  
Stainless Steels ◽  
Chloride Ions ◽  
Main Function ◽  
Marine Atmosphere ◽  
Steel Aisi ◽  
Aisi 316 ◽  
Stainless Steel Aisi

Corrosion, being a destructive process, causes damage in almost all industrial sectors. In this way, it is harmful both from an economic, social and, especially, safety point of view, as it can cause failures in critical equipment and components of an industrial process. At this point, stainless steels are considered the most corrosion resistant metals. The resistance depends on the chemical composition and microstructure, factors that directly influence the passivation of these materials. The resistance is proportionally related to the addition of chromium (Cr) to the mixture, as well as other alloying elements, among which is the molybdenum (Mo), whose main function is to maximize corrosion resistance in the marine atmosphere, as in case of austenitic stainless steel AISI 316 which presents in the chemical composition a percentage of the element Mo. Austenitic stainless steels are applied in instrumentation systems in tubing for reliability in severe atmospheres in accordance with ASTM A269 which establishes the materials applicable to this function. Thus, the present work presents, through a review and case study, Pitting Corrosion of tubings of austenitic stainless steel AISI 316 in the presence of chloride ions (Cl-) coming from the marine atmosphere. The results show that there is no change in the longitudinal and transverse structure for all analyzed tubes, showing a homogeneous austenitic structure, free of intergranular precipitations.

scholarly journals Laser Powder Bed Fusion of Stainless Steel Grades: A Review

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 731 ◽  
Author(s):  
Zitelli ◽  
Folgarait ◽  
Di Schino
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Stainless Steels ◽  
Precipitation Hardening ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Steel Alloys ◽  
Powder Bed ◽  
Steel Grades ◽  
Mechanical Performances

In this paper, the capability of laser powder bed fusion (L-PBF) systems to process stainless steel alloys is reviewed. Several classes of stainless steels are analyzed (i.e., austenitic, martensitic, precipitation hardening and duplex), showing the possibility of satisfactorily processing this class of materials and suggesting an enlargement of the list of alloys that can be manufactured, targeting different applications. In particular, it is reported that stainless steel alloys can be satisfactorily processed, and their mechanical performances allow them to be put into service. Porosities inside manufactured components are extremely low, and are comparable to conventionally processed materials. Mechanical performances are even higher than standard requirements. Micro surface roughness typical of the as-built material can act as a crack initiator, reducing the strength in both quasi-static and dynamic conditions.

Fatigue With Hold Times Simulating NPP Normal Operation Results for Stainless Steel Grades 304L and 347

2017 ◽  
Author(s):  
H. Ertugrul Karabaki ◽  
Jussi Solin ◽  
Marius Twite ◽  
Matthias Herbst ◽  
Jonathan Mann ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Steady State ◽  
Fatigue Life ◽  
Stainless Steels ◽  
Fatigue Behavior ◽  
Material Behavior ◽  
Cyclic Behavior ◽  
Normal Operation ◽  
Major Power ◽  
Steel Grades

The cyclic behavior and endurance of austenitic stainless steels tested under NPP-relevant laboratory conditions has been studied. It had been earlier shown that long intervals between fatigue transients can affect the fatigue performance in stainless steels that are generally used in NPP primary piping. If this can be confirmed, then the transferability between laboratory results, design curves and the fatigue behavior of NPP components during plant operation shall be addressed. In addition to coolant water environmental effects, the material response during steady state normal operation should also be accounted for. Advanced Fatigue Methodologies (AdFaM), a joint project of European research laboratories, vendors and plant operators was focused on empirical and mechanistic investigations to confirm the claimed effects of hold times on fatigue life. Strain-controlled fatigue tests incorporating accelerated hold times at temperatures between 290°C and 420°C were performed on stabilized and non-stabilized stainless steel grades, which are used in Germany and the UK. Two material batches of both alloy types (304L and 347) were studied. The mechanisms responsible for the observed variations in stress response and fatigue life have been investigated using a range of microscopy techniques. The results confirmed the extension of fatigue life due to hold times in both stabilized and non-stabilized grades. This life extension appears to be linked to hold hardening observed in the cyclic behavior of both alloys. Tests incorporating hold times may be more representative of material behavior in NPPs, where temperature transients due to start-ups, shutdowns and major power changes may be separated by long periods of steady state operation. This gives reason to consider the transferability of standard laboratory test data to fatigue assessments of NPP components, and to propose a new factor ( Fhold ) as part of an advanced fatigue methodology and realistic transferability factor: Freal = Fen × Fhold.

Identification of Defects of Stainless Steel Sold with Brand Names, by Studying their Surface Thin Films with Scanning Electron Microscope (SEM)

2014 ◽  
Vol 622-623 ◽  
pp. 53-63 ◽  
Author(s):  
Pervaiz Habibullah
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Stainless Steel ◽  
Stainless Steels ◽  
Induction Furnace ◽  
Brand Names ◽  
Steel Composition ◽  
Sem Images ◽  
Surface Corrosion ◽  
Recycled Material

In the present paper, we have studied the thin films formed on the commercial stainless steel sold under different brand names in Pakistan with the help of SEM, EDX and XRD and have further investigated that how such stainless steels lose their brightness and become dull. A sample of recycled stainless steel melted in induction furnace was taken for study. The analysis of the layer formed is as follows: wt. %, C = 6.55, O = 6.20, Na = 0.47, Mg = 0.31, Al = 2.28, Si = 1.23, Cr = 15.42, Mn = 1.06, Fe = 59.58, Ni = 6.91 Total = 100, Atomic %, C = 21.02 O = 14.93, Na = 0.79, Mg = 0.49, Al = 3.26, Si = 1.68, Cr = 11.43, Mn = 0.74, Fe = 41.12, Ni = 4.53. Stainless steel has austenite structure, is non magnetic and forms fine passive film of Cr (III) oxide, (Cr2O3) which prevents surface corrosion and avoids further corrosion from spreading in metal’s internal structure. Mn and Ni stabilize austenite structure. XRD spectra show presence of αFe2O3 and Cr2O3 and spinal oxides in the film formed on the sample taken for study. SEM images show how this thin film tears. In a sound stainless steel, the film formed is too thin to be visible and metal remains lustrous. The film quickly reforms when surface is scratched (passivation). Mostly stainless steel is recycled and average stainless steel objects manufactured and marketed are composed of above 60% recycled material. Oxide spinals of Mn, Ni, Cr with iron oxide are not very resistive to the corrosion. Recently Duplex stainless steel has been manufactured which contains 50:50 austenite and ferrite and have twice the strength compared to austenite stainless steel. Keywords Recycle stainless steel, composition of thin film with EDX, SEM images, investigation on αFe2O3 and Cr2O3 spinals. In the present paper, we have studied the thin films formed on the commercial stainless steel sold under different brand names in Pakistan* with the help of SEM, EDX and XRD and have further investigated that how such stainless steels lose their brightness and become dull. The sample is austenitic stainless steel.

Prediction of phase distribution and chemical composition during gas carburizing of stainless steels

2004 ◽  
Vol 120 ◽  
pp. 249-257
Author(s):  
T. Turpin ◽  
J. Dulcy ◽  
M. Gantois
Keyword(s):  
Experimental Study ◽  
Stainless Steel ◽  
Chemical Composition ◽  
Phase Transformations ◽  
Stainless Steels ◽  
Phase Distribution ◽  
Carbon Profile ◽  
Reducing Gas ◽  
Gas Carburizing ◽  
Carburizing Process

This article reports a theoretical and experimental study aiming at reducing gas carburizing experiments on stainless steels. This work was carried out to show the advantages of numerical calculations to simulate phase transformations during the gas carburizing process of high alloyed steels. The use of Thermo-Calc and Dictra software allows the metallurgist to predict the optimum thermochemical and heat treatments which are necessary to obtain an accurate carbon profile in a stainless steel. Moreover, the phase distribution and chemical composition can be followed as a function of time and/or distance to gas-solid interface.

Static Strain Aging in Cold Rolled Metastable Austenitic Stainless Steels

2007 ◽  
Vol 539-543 ◽  
pp. 4891-4896 ◽  
Author(s):  
P. Antoine ◽  
B. Soenen ◽  
Nuri Akdut
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Low Temperature ◽  
Yield Strength ◽  
Stainless Steels ◽  
Strain Aging ◽  
Austenitic Stainless Steels ◽  
Static Strain ◽  
Steel Grades ◽  
Cold Rolled

Transformation of austenite to martensite during cold rolling operations is widely used to strengthen metastable austenitic stainless steel grades. Static strain aging (SSA) phenomena at low temperature, typically between 200°C and 400°C, can be used for additional increase in yield strength due to the presence of α’-martensite in the cold rolled metastable austenitic stainless steels. Indeed, SSA in austenitic stainless steel affects mainly in α’-martensite. The SSA response of three industrial stainless steel grades was investigated in order to understand the aspects of the aging phenomena at low temperature in metastable austenitic stainless steels. In this study, the optimization of, both, deformation and time-temperature parameters of the static aging treatment permitted an increase in yield strength up to 300 MPa while maintaining an acceptable total elongation in a commercial 301LN steel grade. Deformed metastable austenitic steels containing the “body-centered” α’-martensite are strengthened by the diffusion of interstitial solute atoms during aging at low temperature. Therefore, the carbon redistribution during aging at low temperature is explained in terms of the microstructural changes in austenite and martensite.

scholarly journals Influence of Partial Replacement of Nickel by Nitrogen on Microstructure and Mechanical Properties of Austenitic Stainless Steel

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
A. Ahmed ◽  
S. N. Ghali ◽  
M. Eissa ◽  
S. A. El Badry
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Induction Furnace ◽  
Solution Treatment ◽  
Nitrogen Pressure ◽  
Partial Replacement ◽  
Different Temperatures ◽  
Open Induction ◽  
Aisi 316 ◽  
Fcc Structure

A new modified austenitic stainless steel has been developed through partial replacement of nickel by nitrogen. Nitrogen stainless steel was produced in 10 kg induction furnace under nitrogen pressure, while reference one, AISI 316 steel grade, was produced in open-induction furnace. Both were cast and hot forged, and the total nitrogen was determined. Furthermore, the produced forged steels were subjected to solution treatment at different temperatures. The microstructure of produced stainless steels was observed. The X-ray diffractmeter and Mossbauer effect spectroscopy were used to follow the phase change in reference and modified steels after different heat treatment temperatures. The influence of grain-size, soluble, and insoluble nitrogen on tensile strength and hardness was investigated. The major phase in the modified steel has a fcc structure similar to the reference one, but with finer grains and more expanded lattice. The yield strength and hardness of the nitrogen-modified stainless steel are higher than the reference steel. On the other hand, the increase of nitrogen content deteriorates the steel ductility.

SCC growth rate measurements and surface oxide film characterization on high SFE austenitic stainless steels in a simulated BWR water environment

2014 ◽  
Vol 1715 ◽  
Author(s):  
S. Ooki ◽  
T. Yonezawa ◽  
M. Watanabe ◽  
H. Kokawa
Keyword(s):  
Growth Rate ◽  
Stainless Steel ◽  
Chemical Composition ◽  
Oxide Film ◽  
Stainless Steels ◽  
Growth Rates ◽  
Oxidation Behavior ◽  
Water Environment ◽  
Austenitic Stainless Steels ◽  
Composition Control

ABSTRACTStress Corrosion Cracking (SCC) has been detected in Boiling Water Reactors (BWRs) on core shrouds and primary water re-circulation piping made of low carbon stainless steels. Material hardening strongly affects SCC propagation behavior, and SCC growth rates increase with increasing hardness of austenitic stainless steels caused by cold work or neutron irradiation.Research work has been conducted in the authors’ laboratories with the aim of improving SCC resistance using chemical composition control of stainless steels. It has been previously reported that high stacking fault energy (SFE) materials showed better SCC resistance than low SFE materials due to hardening being suppressed in high SFE materials. In the present study, SCC growth rate (CGR) tests were performed using 15% cold worked Types 316L and 25Cr-20Ni stainless steels in a simulated BWR water environment. The 25Cr-20Ni stainless steel used has high SFE value due to chemical composition control and measured SCC growth rates were lower than those of low SFE stainless steels.However, oxidation behavior is one of the more important factors influencing SCC of austenitic stainless steels in addition to material hardening behavior, and the influence of the chemical composition control necessary to increase SFE on oxidation behavior in BWR primary coolants is still unclear. In this study, therefore, immersion tests using Types 316L and 25Cr-20Ni stainless steel specimens were also conducted in the simulated BWR water environment. The surface oxide films on the specimens were then analyzed with micro-Raman spectroscopy and glow discharge optical emission spectroscopy in order to help clarify the oxidation behavior.The results of these tests and analyses showed that the NiFe2O4 content of the outer oxide layers on the high SFE stainless steels was higher than that on the low SFE stainless steels. The inner oxide film on the 25Cr-20Ni stainless steel also had a high chromium content.Based on the above results, SCC resistance and oxidation behavior of high SFE austenitic stainless steels in a simulated BWR water environment will be discussed.

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