Advances in Low-carbon and Stainless Steels

A special issue of Metals (ISSN 2075-4701).

Deadline for manuscript submissions: closed (31 May 2019) | Viewed by 63848

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Special Issue Editors


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Guest Editor
Institute for Frontier Materials, Deakin University, Victoria, Australia
Interests: steels; thermomechanical processing; phase transformation; corrosion; wear; grain boundary engineering; solidification; severe plastic deformation; additive manufacturing; high entropy alloys; texture

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Guest Editor
Centre for Advanced Steels Research, Materials and Mechanical Engineering, University of Oulu, 90014 Oulu, Finland
Interests: materials engineering; physical metallurgy; mechanical metallurgy; physical and numerical simulation and modeling
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Special Issue Information

Dear Colleagues,

This Special Issue of Metals, is dedicated to the recent advances in low-carbon and stainless steels. Although these types of steels are not new, they are still receiving a great attention from both research and industry sectors, due to their wide range of applications and their complex microstructure/behavior under different conditions. The microstructure of low carbon and stainless steels resulted from solidification, phase transformation and hot working is complex, which, in turn, affects their performance under different working conditions. A detailed understanding of the microstructure/property/performance for these steels has been the aim of steel scientists for a long time.

For this special issue, we are inviting papers on different aspects of these steels including their solidification, thermomechanical processing, phase transformation, texture, etc., and their corrosion, wear, fatigue and creep properties. We are also interested in papers which use predictive models at different scales to describe processing and/or properties in these steels. Finally, we particularly welcome novel research on duplex stainless steels due to their current significant growth.

Dr. Nima Haghdadi
Prof. Mahesh Somani
Guest Editors

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Keywords

  • Stainless steels
  • Low carbon steels
  • Phase transformation
  • Thermomechanical processing
  • Solidification
  • Constitutive analysis
  • Grain boundary engineering
  • Corrosion
  • Wear

Published Papers (14 papers)

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Research

15 pages, 9658 KiB  
Article
Rational Alloy Design of Niobium-Bearing HSLA Steels
by Rami A. Almatani and Anthony J. DeArdo
Metals 2020, 10(3), 413; https://doi.org/10.3390/met10030413 - 23 Mar 2020
Cited by 3 | Viewed by 3172
Abstract
In the 61 years that niobium has been used in commercial steels, it has proven to be beneficial via several properties, such as strength and toughness. Over this time, numerous studies have been performed and papers published showing that both the strength and [...] Read more.
In the 61 years that niobium has been used in commercial steels, it has proven to be beneficial via several properties, such as strength and toughness. Over this time, numerous studies have been performed and papers published showing that both the strength and toughness can be improved with higher Nb additions. Earlier studies have verified this trend for steels containing up to about 0.04 wt.% Nb. Basic studies have shown that the addition of Nb increases the recrystallization-stop temperature, T5% or Tnr. These same studies have shown that with up to about 0.05 wt.% of Nb, the T5% temperature increases in the range of finish rolling, which is the basis of controlled rolling. These studies also have shown that at very high Nb levels, exceeding approximately 0.06 wt.% Nb, the recrystallization-stop temperature or T5% can increase into the temperature range of rough rolling, and this could result in insufficient grain refinement and recrystallization during rough rolling. However, the question remains as to how much Nb can be added before the detriments outweigh the benefits. While the benefits are easily observed and discussed, the detriments are not. These detriments at high Nb levels include cost, undissolved Nb particles, weldability issues, higher mill loads and roll wear and the lessening of grain refinement that might otherwise occur during plate rough rolling. This loss of grain refinement is important, since coarse grained microstructures often result in failure in the drop weight tear testing of the plate and pipe. The purpose of this paper is to discuss the practical limits of Nb microalloying in controlled rolled low carbon linepipe steels of gauges ranging from 12 to 25 mm in thickness. Full article
(This article belongs to the Special Issue Advances in Low-carbon and Stainless Steels)
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12 pages, 6402 KiB  
Article
Investigation on the Formation of Cr-Rich Precipitates at the Interphase Boundary in Type 430 Stainless Steel Based on Austenite–Ferrite Transformation Kinetics
by Tao Jia, Run Ni, Hanle Wang, Jicheng Shen and Zhaodong Wang
Metals 2019, 9(10), 1045; https://doi.org/10.3390/met9101045 - 26 Sep 2019
Cited by 9 | Viewed by 2574
Abstract
The Cr-rich precipitates at the interphase boundary in stainless steels not only lead to the sensitization, which further induces the intergranular corrosion and intergranular stress corrosion cracking, but also significantly deteriorate the ductility and toughness. In this work, the formation of Cr-rich precipitates [...] Read more.
The Cr-rich precipitates at the interphase boundary in stainless steels not only lead to the sensitization, which further induces the intergranular corrosion and intergranular stress corrosion cracking, but also significantly deteriorate the ductility and toughness. In this work, the formation of Cr-rich precipitates at the interphase boundary in type 430 stainless steel was investigated from the perspective of austenite–ferrite transformation kinetics. Cyclic heat treatment was firstly conducted to reveal the kinetic mode of transformation behavior, i.e., local equilibrium or para equilibrium. Subsequently, interrupted quenching during continuous cooling was carried out, which illustrated clearly the relevance of the formation of interphase Cr-rich precipitates to the Cr enrichment adjacent to the interphase boundary as revealed by line scanning of energy dispersive spectroscopy (EDS). Finally, this enrichment of Cr was interpreted by DICTRA simulation, which is based on the determined kinetic mode for austenite–ferrite transformation. This work has, for the first time, established the correlation between the formation of interphase Cr-rich precipitates and the austenite–ferrite transformation kinetics. Full article
(This article belongs to the Special Issue Advances in Low-carbon and Stainless Steels)
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11 pages, 4081 KiB  
Article
Enhanced Corrosion Resistance of SA106B Low-Carbon Steel Fabricated by Rotationally Accelerated Shot Peening
by Chaonan Lei, Xudong Chen, Yusheng Li, Yuefeng Chen and Bin Yang
Metals 2019, 9(8), 872; https://doi.org/10.3390/met9080872 - 8 Aug 2019
Cited by 5 | Viewed by 3227
Abstract
The corrosion resistance of a SA106B carbon steel with a gradient nanostructure fabricated by rotationally accelerated shot peening (RASP) for 5, 10, 15 and 20 min was investigated. Electrochemical tests were carried out in the 0.05 M H2SO4 + 0.05 [...] Read more.
The corrosion resistance of a SA106B carbon steel with a gradient nanostructure fabricated by rotationally accelerated shot peening (RASP) for 5, 10, 15 and 20 min was investigated. Electrochemical tests were carried out in the 0.05 M H2SO4 + 0.05 M Na2SO4 and 0.2 M NaCl + 0.05 M Na2SO4 solutions. The experimental results showed that the sample RASP-processed for 5 min exhibited the best corrosion resistance among them. TEM analysis confirmed that the cementite dissolution and formation of nanograins, which improved the corrosion resistance of the steel. Prominent micro-cracks and holes were produced in the samples when the RASP was processed for more than 5 min, resulting in the decrease of corrosion resistance. Full article
(This article belongs to the Special Issue Advances in Low-carbon and Stainless Steels)
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18 pages, 22168 KiB  
Article
Fatigue Behavior of Metastable Austenitic Stainless Steels in LCF, HCF and VHCF Regimes at Ambient and Elevated Temperatures
by Marek Smaga, Annika Boemke, Tobias Daniel, Robert Skorupski, Andreas Sorich and Tilmann Beck
Metals 2019, 9(6), 704; https://doi.org/10.3390/met9060704 - 21 Jun 2019
Cited by 28 | Viewed by 5222
Abstract
Corrosion resistance has been the main scope of the development in high-alloyed low carbon austenitic stainless steels. However, the chemical composition influences not only the passivity but also significantly affects their metastability and, consequently, the transformation as well as the cyclic deformation behavior. [...] Read more.
Corrosion resistance has been the main scope of the development in high-alloyed low carbon austenitic stainless steels. However, the chemical composition influences not only the passivity but also significantly affects their metastability and, consequently, the transformation as well as the cyclic deformation behavior. In technical applications, the austenitic stainless steels undergo fatigue in low cycle fatigue (LCF), high cycle fatigue (HCF), and very high cycle fatigue (VHCF) regime at room and elevated temperatures. In this context, the paper focuses on fatigue and transformation behavior at ambient temperature and 300 °C of two batches of metastable austenitic stainless steel AISI 347 in the whole fatigue regime from LCF to VHCF. Fatigue tests were performed on two types of testing machines: (i) servohydraulic and (ii) ultrasonic with frequencies: at (i) 0.01 Hz (LCF), 5 and 20 Hz (HCF) and 980 Hz (VHCF); and at (ii) with 20 kHz (VHCF). The results show the significant influence of chemical composition and temperature of deformation induced α´-martensite formation and cyclic deformation behavior. Furthermore, a “true” fatigue limit of investigated metastable austenitic stainless steel AISI 347 was identified including the VHCF regime at ambient temperature and elevated temperatures. Full article
(This article belongs to the Special Issue Advances in Low-carbon and Stainless Steels)
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12 pages, 7023 KiB  
Article
The Effect of Rapid Heating and Fast Cooling on the Transformation Behavior and Mechanical Properties of an Advanced High Strength Steel (AHSS)
by Juan Pablo Pedraza, Rafael Landa-Mejia, Omar García-Rincon and C. Isaac Garcia
Metals 2019, 9(5), 545; https://doi.org/10.3390/met9050545 - 10 May 2019
Cited by 16 | Viewed by 5522
Abstract
The major goal of this work was to study the effect of rapid heating and fast cooling on the transformation behavior of 22MnB5 steel. The effect of the initial microstructure (ferrite + pearlite or fully spheroidized) on the transformation behavior of austenite (during [...] Read more.
The major goal of this work was to study the effect of rapid heating and fast cooling on the transformation behavior of 22MnB5 steel. The effect of the initial microstructure (ferrite + pearlite or fully spheroidized) on the transformation behavior of austenite (during intercritical and supercritical annealing) in terms of heating rates (2.5, 30 & 200 °C/s) and fast cooling, i.e., 300 °C/s rate, were studied. As expected, the kinetics of austenite nucleation and growth were strongly related to the heating rates. Similarly, the carbon content of the austenite was higher at lower intercritical annealing temperatures, particularly when slower heating rates were used. The supercritical temperatures used in this study were similar to those used during commercial hot stamping operations, i.e., 845 and 895 °C, respectively, followed by a fast cooling rate. The prior austenite grain size (PAGS) was not strongly influenced by the nature of the initial microstructure, heating rate, reheating temperatures (845 or 895 °C), at 30 s holding time. The decomposition of austenite using fast cooling rates was examined. The results showed that 100% martensite was not obtained. The observed low temperature transformation products consisted of mixtures of martensite-bainite plus undissolved Fe3C carbides and small amounts of martensite-austenite (M-A). At higher supercritical temperatures, i.e., 1000 °C and 1050 °C, the final microstructure showed an increase in the volume fraction of martensite and a decrease in the volume fraction of bainite. The Fe3C and the M-A microconstituent were not observed. The best combination of tensile properties was obtained on samples reheated in the lower temperature range (845 to 895 °C). Interestingly, when the samples where reheated at the higher temperature range (1000 to 1050 °C) and fast cooled, the results of the mechanical properties did not exhibit significantly higher strength levels independent of heating rate or initial microstructural condition. This can be attributed to the change in the microstructural balance %martensite+%bainite as the reheating temperature increases. The results of this study are presented and discussed. Full article
(This article belongs to the Special Issue Advances in Low-carbon and Stainless Steels)
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17 pages, 4014 KiB  
Article
Quenching and Partitioning of Multiphase Aluminum-Added Steels
by Tuomo Nyyssönen, Olli Oja, Petri Jussila, Ari Saastamoinen, Mahesh Somani and Pasi Peura
Metals 2019, 9(3), 373; https://doi.org/10.3390/met9030373 - 22 Mar 2019
Cited by 7 | Viewed by 4555
Abstract
The quenching and partitioning response following intercritical annealing was investigated for three lean TRIP-type high-Al steel compositions. Depending on the intercritical austenite fraction following annealing, the steels assumed either a ferrite/martensite/retained austenite microstructure or a multiphase structure with ferritic, bainitic and martensitic constituents [...] Read more.
The quenching and partitioning response following intercritical annealing was investigated for three lean TRIP-type high-Al steel compositions. Depending on the intercritical austenite fraction following annealing, the steels assumed either a ferrite/martensite/retained austenite microstructure or a multiphase structure with ferritic, bainitic and martensitic constituents along with retained austenite. The amount of retained austenite was found to correlate with the initial quench temperature and, depending on the intercritical annealing condition prior to initial quenching, with the uniform and ultimate elongations measured in tensile testing. Full article
(This article belongs to the Special Issue Advances in Low-carbon and Stainless Steels)
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15 pages, 4267 KiB  
Article
Hot Forming of Ultra-Fine-Grained Multiphase Steel Products Using Press Hardening Combined with Quenching and Partitioning Process
by Esa Pirkka Vuorinen, Almila Gülfem Özügürler, John Christopher Ion, Katarina Eriksson, Mahesh Chandra Somani, Leo Pentti Karjalainen, Sébastien Allain and Francisca Garcia Caballero
Metals 2019, 9(3), 357; https://doi.org/10.3390/met9030357 - 20 Mar 2019
Cited by 6 | Viewed by 3764
Abstract
Hot forming combined with austempering and quenching and partitioning (QP) processes have been used to shape two cold rolled high silicon steel sheets into hat profiles. Thermal simulation on a Gleeble instrument was employed to optimize processing variables to achieve an optimum combination [...] Read more.
Hot forming combined with austempering and quenching and partitioning (QP) processes have been used to shape two cold rolled high silicon steel sheets into hat profiles. Thermal simulation on a Gleeble instrument was employed to optimize processing variables to achieve an optimum combination of strength and ductility in the final parts. Microstructures were characterized using optical and scanning electron microscopy and X-ray diffraction. Tensile strengths (Rm) of 1190 and 1350 MPa and elongations to fracture (A50mm) of 8.5 and 7.4%, were achieved for the two high-silicon steels having 0.15 and 0.26 wt % C, respectively. Preliminary results show that press hardening together with a QP heat treatment is an effective method of producing components with high strength and reasonable tensile ductility from low carbon containing steels that have the potential for carbide free bainite formation. The QP treatment resulted in faster austenite decomposition during partitioning in the steels in comparison with an austempering treatment. Full article
(This article belongs to the Special Issue Advances in Low-carbon and Stainless Steels)
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12 pages, 3878 KiB  
Article
Dynamic Phase Transformation Behavior of a Nb-microalloyed Steel during Roughing Passes at Temperatures above the Ae3
by Samuel F. Rodrigues, Fulvio Siciliano, Clodualdo Aranas, Jr., Eden S. Silva, Gedeon S. Reis, Mohammad Jahazi and John J. Jonas
Metals 2019, 9(3), 334; https://doi.org/10.3390/met9030334 - 15 Mar 2019
Cited by 6 | Viewed by 2854
Abstract
A five-pass torsion simulation of the roughing passes applied during hot plate rolling was performed in the single-phase austenite region of a Nb-microalloyed steel under continuous cooling conditions. The deformation temperatures were approximately half-way between the Ae3 and the delta ferrite formation [...] Read more.
A five-pass torsion simulation of the roughing passes applied during hot plate rolling was performed in the single-phase austenite region of a Nb-microalloyed steel under continuous cooling conditions. The deformation temperatures were approximately half-way between the Ae3 and the delta ferrite formation temperature (i.e., 250 °C above the Ae3) in which the free energy difference of austenite and ferrite is at maximum. The microstructures in-between passes were analyzed to characterize and quantify the occurrence of deformation-induced dynamic phase transformation. It was observed that about 7% of austenite transforms into ferrite right after the final pass. The results are consistent with the calculated critical strains and driving forces which indicate that dynamic transformation (DT) can take place at any temperature above the Ae3. This mechanism occurs even with the presence of high Nb in the material, which is known to retard and hinder the occurrence of DT by means of pinning and solute drag effects. The calculated cooling rate during quenching and the time–temperature–transformation curves of the present material further verified the existence of dynamically transformed ferrite. Full article
(This article belongs to the Special Issue Advances in Low-carbon and Stainless Steels)
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12 pages, 2957 KiB  
Article
Transformation-Induced Plasticity in Super Duplex Stainless Steel F55-UNS S32760
by Andrea Francesco Ciuffini, Silvia Barella, Cosmo Di Cecca, Andrea Di Schino, Andrea Gruttadauria, Giuseppe Napoli and Carlo Mapelli
Metals 2019, 9(2), 191; https://doi.org/10.3390/met9020191 - 6 Feb 2019
Cited by 4 | Viewed by 2746
Abstract
Due to their unique combination of properties, Super Duplex Stainless Steels (SDSSs) are materials of choice in many industries. Their applications and markets are growing continuously, and without any doubt, there is a great potential for further volume increase. In recent years, intensive [...] Read more.
Due to their unique combination of properties, Super Duplex Stainless Steels (SDSSs) are materials of choice in many industries. Their applications and markets are growing continuously, and without any doubt, there is a great potential for further volume increase. In recent years, intensive research has been performed on lean SDSSs improving mechanical properties exploiting the lack of nickel to generate metastable γ-austenite, resulting in transformation-induced plasticity (TRIP) effect. In the present work, a commercial F55-UNS S32760 SDSS have been studied coupling its microstructural features, especially secondary austenitic precipitates, and tensile properties, after different thermal treatments. First, the investigated specimens have been undergone to a thermal treatment solution, and then, to an annealing treatment with different holding times, in order to simulate the common hot-forming industrial practice. The results of microstructural investigations and mechanical testing highlight the occurrence of TRIP processes. This feature has been related to the Magee effect, concerning the secondary austenitic precipitates nucleated via martensitic-shear transformation. Full article
(This article belongs to the Special Issue Advances in Low-carbon and Stainless Steels)
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13 pages, 4860 KiB  
Article
Effect of Carbon Partitioning, Carbide Precipitation, and Grain Size on Brittle Fracture of Ultra-High-Strength, Low-Carbon Steel after Welding by a Quenching and Partitioning Process
by Farnoosh Forouzan, M. Agustina Guitar, Esa Vuorinen and Frank Mücklich
Metals 2018, 8(10), 747; https://doi.org/10.3390/met8100747 - 23 Sep 2018
Cited by 6 | Viewed by 5340
Abstract
To improve the weld zone properties of Advanced High Strength Steel (AHSS), quenching and partitioning (Q&P) has been used immediately after laser welding of a low-carbon steel. However, the mechanical properties can be affected for several reasons: (i) The carbon content and amount [...] Read more.
To improve the weld zone properties of Advanced High Strength Steel (AHSS), quenching and partitioning (Q&P) has been used immediately after laser welding of a low-carbon steel. However, the mechanical properties can be affected for several reasons: (i) The carbon content and amount of retained austenite, bainite, and fresh martensite; (ii) Precipitate size and distribution; (iii) Grain size. In this work, carbon movements during the partitioning stage and prediction of Ti (C, N), and MoC precipitation at different partitioning temperatures have been simulated by using Thermocalc, Dictra, and TC-PRISMA. Verification and comparison of the experimental results were performed by optical microscopy, X-ray diffraction (XRD), Scanning Electron Microscop (SEM), and Scanning Transmission Electron Microscopy (STEM), and Energy Dispersive Spectroscopy (EDS) and Electron Backscatter Scanning Diffraction (EBSD) analysis were used to investigate the effect of martensitic/bainitic packet size. Results show that the increase in the number density of small precipitates in the sample partitioned at 640 °C compensates for the increase in crystallographic packets size. The strength and ductility values are kept at a high level, but the impact toughness will decrease considerably. Full article
(This article belongs to the Special Issue Advances in Low-carbon and Stainless Steels)
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22 pages, 5003 KiB  
Article
Flow-Accelerated Corrosion of Type 316L Stainless Steel Caused by Turbulent Lead–Bismuth Eutectic Flow
by Tao Wan and Shigeru Saito
Metals 2018, 8(8), 627; https://doi.org/10.3390/met8080627 - 9 Aug 2018
Cited by 19 | Viewed by 6186
Abstract
Lead–bismuth eutectic (LBE), a heavy liquid metal, is an ideal candidate coolant material for Generation-IV fast reactors and accelerator-driven systems (ADSs), but LBE is also known to pose a considerable corrosive threat to its container. However, the susceptibility of the candidate container material, [...] Read more.
Lead–bismuth eutectic (LBE), a heavy liquid metal, is an ideal candidate coolant material for Generation-IV fast reactors and accelerator-driven systems (ADSs), but LBE is also known to pose a considerable corrosive threat to its container. However, the susceptibility of the candidate container material, 316L stainless steel (SS), to flow-accelerated corrosion (FAC) under turbulent LBE flow, is not well understood. In this study, an LBE loop, referred to as JLBL-1, was used to experimentally study the behavior of 316L SS when subjected to FAC for 3000 h under non-isothermal conditions. An orificed tube specimen, consisting of a straight tube that abruptly narrows and widens at each end, was installed in the loop. The specimen temperature was 450 °C, and a temperature difference between the hottest and coldest legs of the loop was 100 °C. The oxygen concentration in the LBE was lower than 10−8 wt %. The Reynolds number in the test specimen was approximately 5 × 104. The effects of various hydrodynamic parameters on FAC behavior were studied with the assistance of computational fluid dynamics (CFD) analyses, and then a mass transfer study was performed by integrating a corrosion model into the CFD analyses. The results show that the local turbulence level affects the mass concentration distribution in the near-wall region, and therefore, the mass transfer coefficient across the solid/liquid interface. The corrosion depth was predicted on the basis of the mass transfer coefficient obtained in the numerical simulation and was compared with that obtained in the loop. For the abrupt narrow part, the predicted corrosion depth was comparable with the measured corrosion depth, as was the abrupt wide part after involving the wall roughness effects in the prediction; for the straight tube part, the predicted corrosion depth is about 1.3–3.5 times the average experimental corrosion depth, and the possible reason for this discrepancy was provided. Full article
(This article belongs to the Special Issue Advances in Low-carbon and Stainless Steels)
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16 pages, 1284 KiB  
Article
Effects of Chemical Composition and Austenite Deformation on the Onset of Ferrite Formation for Arbitrary Cooling Paths
by Aarne Pohjonen, Mahesh Somani and David Porter
Metals 2018, 8(7), 540; https://doi.org/10.3390/met8070540 - 12 Jul 2018
Cited by 6 | Viewed by 5306
Abstract
We present a computational method for calculating the phase transformation start for arbitrary cooling paths and for different steel compositions after thermomechanical treatments. We apply the method to quantitatively estimate how much austenite deformation and how many different alloying elements affect the transformation [...] Read more.
We present a computational method for calculating the phase transformation start for arbitrary cooling paths and for different steel compositions after thermomechanical treatments. We apply the method to quantitatively estimate how much austenite deformation and how many different alloying elements affect the transformation start at different temperatures. The calculations are done for recrystallized steel as well as strain hardened steel, and the results are compared. The method is parameterized using continuous cooling transformation (CCT) data as an input, and it can be easily adapted for different thermomechanical treatments when corresponding CCT data is available. The analysis can also be used to obtain estimates for the range of values for parameters in more detailed microstructure models. Full article
(This article belongs to the Special Issue Advances in Low-carbon and Stainless Steels)
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14 pages, 8480 KiB  
Article
Effect of Cold Deformation on Microstructures and Mechanical Properties of Austenitic Stainless Steel
by Deming Xu, Xiangliang Wan, Jianxin Yu, Guang Xu and Guangqiang Li
Metals 2018, 8(7), 522; https://doi.org/10.3390/met8070522 - 6 Jul 2018
Cited by 37 | Viewed by 7756
Abstract
In this paper, the effect of cold deformation on the microstructures and mechanical properties of 316LN austenitic stainless steel (ASS) was investigated. The results indicated that the content of martensite increased as the cold rolling reduction also increased. Meanwhile, the density of the [...] Read more.
In this paper, the effect of cold deformation on the microstructures and mechanical properties of 316LN austenitic stainless steel (ASS) was investigated. The results indicated that the content of martensite increased as the cold rolling reduction also increased. Meanwhile, the density of the grain boundary in the untransformed austenite structure of CR samples increased as the cold reduction increased from 10% to 40%, leading to a decreased size of the untransformed austenite structure. These two factors contribute to the improvement of strength and the decrease of ductility. High yield strengths (780–968 MPa) with reasonable elongations (30.8–27.4%) were achieved through 20–30% cold rolling. The 10–30% cold-rolled (CR) samples with good ductility had a good strain hardening ability, exhibiting a three-stage strain hardening behavior. Full article
(This article belongs to the Special Issue Advances in Low-carbon and Stainless Steels)
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13 pages, 6312 KiB  
Article
Corrosion Behavior Difference in Initial Period for Hot-Rolled and Cold-Rolled 2205 Duplex Stainless Steels
by Tao Gao, Jian Wang, Qi Sun and Peide Han
Metals 2018, 8(6), 407; https://doi.org/10.3390/met8060407 - 1 Jun 2018
Cited by 5 | Viewed by 4472
Abstract
Precipitate phases often play an important role on the corrosion resistance of 2205 Duplex stainless steels (DSS). In the present paper, the microstructure and the corrosion resistance of the hot-rolled and cold-rolled 2205 steels aged for different times at 850 °C was investigated [...] Read more.
Precipitate phases often play an important role on the corrosion resistance of 2205 Duplex stainless steels (DSS). In the present paper, the microstructure and the corrosion resistance of the hot-rolled and cold-rolled 2205 steels aged for different times at 850 °C was investigated through XRD, SEM, and potentiodynamic polarization. It was discovered that the Chi(χ) phase and Sigm(σ) phase were precipitated in turn following the aging treatment of the hot-rolled and cold-rolled steels, but the precipitate amount in the cold-rolled samples was significantly higher when compared to the hot-rolled samples. The corrosion resistance of the solution-annealed cold-rolled samples was similar to the hot-rolled samples, but the corrosion resistance of the cold-rolled sample with precipitate was weaker when compared to the hot-rolled sample following aging treatment. Pitting preferentially initiates in the Cr-depleted region from the σ phase in the aged hot-rolled 2205, becoming increasingly severe during aging for a long lime. Adversely, the initiation of pitting corrosion might occur at the phase boundary, defects, and martensite in the aged cold-rolled 2205. The σ phase was further selectively dissolved through the electrochemical method to investigate the difference in microstructure and corrosion behavior of the hot-rolled and cold-rolled 2205 duplex stainless steels. Full article
(This article belongs to the Special Issue Advances in Low-carbon and Stainless Steels)
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