scholarly journals Influence of Copper Addition on Sigma Phase Precipitation during Hot Deformation of Duplex Steel

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1665
Author(s):  
Grzegorz Stradomski ◽  
Arkadiusz Szarek ◽  
Dariusz Rydz
Keyword(s):  
Hot Deformation ◽  
Sigma Phase ◽  
Austenitic Steels ◽  
Multiphase Microstructure ◽  
Copper Addition ◽  
Cast Steels ◽  
Duplex Steel ◽  
Similar Chemical ◽  
Precipitation Phenomena ◽  
The Many

The paper presents an experimental study on microstructure changes in duplex steel after hot deformation. Duplex steels and cast steels are characterized by a multiphase microstructure. They are relatively new materials with great contributions to the many fields of industries. Due to the fact of deforming two different phase austenite and ferrite those materials have a complex plasticity. This work is a continuation and complementation of previous works and is a significant supplement to information presented in them. The article concerns precipitation phenomena and changes in the microstructure of two grades of ferritic-austenitic steels: X2CrNiMoN25-7-4 and X2CrNiMoCuN25-6-3. Those steels have a very similar chemical composition, differing by only 2.5% copper content. An important aspect presented in the work is we observed that adding 2.5% copper prevented precipitation of the destructive sigma phase during the hot deformation.

scholarly journals The Analysis of AISI A3 Type Ferritic-Austenitic Cast Steel Crystallization Mechanism

2017 ◽  
Vol 17 (3) ◽  
pp. 229-233
Author(s):  
G. Stradomski
Keyword(s):  
Power Plants ◽  
Cast Steel ◽  
Construction Materials ◽  
Austenitic Steels ◽  
High Alloy ◽  
Working Environments ◽  
Cast Steels ◽  
Derivative Analysis ◽  
Duplex Steel ◽  
The Rich

AbstractHigh-alloy corrosion-resistant ferritic-austenitic steels and cast steels are a group of high potential construction materials. This is evidenced by the development of new alloys both low alloys grades such as the ASTM 2101 series or high alloy like super or hyper duplex series 2507 or 2707 [1-5]. The potential of these materials is also presented by the increasing frequency of sintered components made both from duplex steel powders as well as mixtures of austenitic and ferritic steels [6, 7]. This article is a continuation of the problems presented in earlier works [5, 8, 9] and its inspiration were technological observed problems related to the production of duplex cast steel.The analyzed AISI A3 type cast steel is widely used in both wet exhaust gas desulphurisation systems in coal fired power plants as well as in aggressive working environments. Technological problems such as hot cracking presented in works [5, 8], with are effects of the rich chemical composition and phenomena occurring during crystallization, must be known to the technologists.The presented in this work phenomena which occur during the crystallization and cooling of ferritic-austenitic cast steel were investigated using numerical methods with use of the ThermoCalc and FactSage® software, as well with use of experimental thermal-derivative analysis.

scholarly journals Fine Structure of Shear Bands Formed during Hot Deformation of Two Austenitic Steels

2004 ◽  
Vol 45 (7) ◽  
pp. 2157-2164 ◽  
Author(s):  
Pavel Cizek ◽  
Fang Bai ◽  
W.Mark Rainforth ◽  
John H. Beynon
Keyword(s):  
Fine Structure ◽  
Hot Deformation ◽  
Shear Bands ◽  
Austenitic Steels

scholarly journals Complex precipitation phenomena in strip cast steels with high sulfur and copper contents

2016 ◽  
Vol 49 (5) ◽  
pp. 1777-1785 ◽  
Author(s):  
T. Dorin ◽  
A. Taylor ◽  
K. Wood ◽  
J. Wang ◽  
P. D. Hodgson ◽  
...  
Keyword(s):  
Solid Solution ◽  
Volume Fraction ◽  
Equilibrium Concentration ◽  
Atom Probe ◽  
Strip Casting ◽  
Cu Content ◽  
Cast Steels ◽  
Strip Cast ◽  
Precipitation Phenomena ◽  
Cast Condition

A series of three steel alloys with increasing Cu and S concentrations has been prepared by simulated direct strip casting. It was found that the rapid solidification that occurs during direct strip casting results in the formation of a high number density of fine MnS precipitates, while Cu was retained in solid solution above equilibrium concentration. Upon ageing the MnS particles were found to coarsen and increase in volume fraction, indicating that some S was retained in solid solution in the as-cast condition. Ageing also resulted in the precipitation of Cu-rich precipitates. A new method to determine precipitate composition from small-angle neutron scattering is presented. This methodology, in conjunction with atom-probe tomography, has been used to show that the composition of the Cu-rich precipitates depends on the alloy's bulk Cu content.

scholarly journals Advanced Mechanical Strength in Post Heat Treated SLM 2507 at Room and High Temperature Promoted by Hard/Ductile Sigma Precipitates

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 199 ◽  
Author(s):  
Kamran Saeidi ◽  
Sajid Alvi ◽  
Frantisek Lofaj ◽  
Valeri Ivanov Petkov ◽  
Farid Akhtar
Keyword(s):  
Tensile Strength ◽  
Stainless Steel ◽  
Mechanical Strength ◽  
Sigma Phase ◽  
Heat Treating ◽  
Tribological Behaviour ◽  
Wear Properties ◽  
Slow Cooling ◽  
Heat Treated ◽  
Duplex Steel

Duplex stainless steel, 71 wt.% austenite, 13 wt.% ferrite and 16 wt.% sigma, was made upon heat treating of fully ferritic as-built selective laser melted (SLM) 2507 stainless steel at 1200 °C. Formation of sigma phase in the heat treated SLM 2507 was investigated using optical microscopy and scanning electron microscopy (SEM). The heat treated SLM 2507 demonstrated a yield strength of 686 MPa, ultimate tensile strength of 920 MPa and an elongation of 1.8% at room temperature with a brittle fracture morphology. Precipitation of sigma phase during heat treatment and slow cooling improved the mechanical and wear properties at high temperatures (1200 °C and 800 °C, respectively). The tensile strength and elongation of the heat treated SLM 2507 was measured 400 MPa and 20% as compared to casted duplex steel with 19 MPa and 30% elongation at 1200 °C. The 20 times higher mechanical strength as compared to casted duplex steel was attributed to sigma precipitates. Tribological behaviour of heat treated duplex SLM 2507 containing sigma at 800 °C showed very low wear rate of 4.5 × 10−5 mm3/mN compared to casted duplex steel with 1.6 × 10−4 mm3/mN.

Secondary Phases Precipitation in the 2510 Duplex Stainless Steel

2009 ◽  
Vol 1242 ◽  
Author(s):  
Arturo Reyes ◽  
Irene Calliari ◽  
Emilio Ramous ◽  
Michela Zanellato ◽  
Mattia Merlin
Keyword(s):  
Stainless Steel ◽  
Stainless Steels ◽  
Sigma Phase ◽  
Secondary Phases ◽  
Heat Treated ◽  
Duplex Steel ◽  
Super Duplex Stainless Steels ◽  
History Of ◽  
Short Times ◽  
Steel Heat

ABSTRACTA lot of duplex and super duplex stainless steels are prone to secondary phases but with different sequence and kinetic which depend on the chemical composition and thermo-mechanical history of the steel. In this paper the results of secondary phase's determination in a welding grade 2510 duplex steel, heat treated at 850–1050°C for 3–30 min are presented. The precipitation stars at grain boundaries with a consistent ferrite transformation for short times. The noses of the TTP curves are at 1000°C (sigma phase) and at 900°C (chi phase) with a partial transformation of chi to sigma, as evidenced in 2205 and 2507 grades.

Application of ATR-FTIR spectroscopy for the identification of chemical functional groups in kerogens and fossil resins.

2020 ◽  
Author(s):  
Yen Yu Chen ◽  
Ying Ju Chang
Keyword(s):  
Functional Groups ◽  
Organic Matters ◽  
Analytical Technique ◽  
Similar Chemical ◽  
Stretching Vibration ◽  
Infrared Spectrometer ◽  
Reflectance Ftir ◽  
The Many ◽  
Many Sources ◽  
Fossil Resins

<p>Organic matters, such as oil, kerogen, fossil resins have different chemical functional groups. The complexity of chemical functional groups derives from the many sources of original contributing organic matter and long-term chemical and physical changes over geologic time. Fourier transform infrared spectrometer attenuated total reflectance (FTIR-ATR) can quantify the abundance of chemical functional groups and is a sensitive, high resolution and non-destructive analytical technique. The aim of this study was to characterize the spectral behavior and chemical structure of organic matters. In order to correlate organic matters of different types with its infrared spectra. The results show that FTIR-ATR spectra of oil contain intense aliphatic C-H stretching vibration in 2960 cm<sup>-1</sup>,2925 cm<sup>-1</sup>,2850 cm<sup>-1</sup> region relative to the C–H (CH<sub>3</sub>) scissoring vibration at 1470 cm<sup>-1</sup> and C=C aromatic ring stretching vibration at 1640 cm<sup>-1</sup>. We apply FTIR-ATR analyses for evaluating oil potential of kerogens. The longest aliphatic chains having the least amount of branching testifying to the highest oil generating potential. The similar locality of fossil resins has a similar chemical vibration ratio of C-H stretching (2925 cm<sup>-1</sup>,2850 cm<sup>-1</sup>) and C-H scissoring (1470 cm<sup>-1</sup>). In consequence, the analysis providing a rapid means of assessing organic matters and oil potential, and it can also rapidly identification the botanical origin of fossil resins.</p><p></p>

Deformation Mechanisms in High-Al Bearing High-Mn TWIP Steels in Hot Compression and in Tension at Low Temperatures

2007 ◽  
Vol 550 ◽  
pp. 217-222 ◽  
Author(s):  
Atef S. Hamada ◽  
L. Pentti Karjalainen ◽  
Mahesh C. Somani ◽  
R.M. Ramadan
Keyword(s):  
Austenitic Steel ◽  
Work Hardening ◽  
Hot Deformation ◽  
Low Temperatures ◽  
Deformation Behaviour ◽  
Tensile Tests ◽  
Mechanical Twinning ◽  
Al Content ◽  
Duplex Steel ◽  
Twip Steels

The hot deformation behaviour of two high-Mn (23-24 wt-%) TWIP steels containing 6 and 8 wt-% Al with the fully austenitic and duplex microstructures, respectively, has been investigated at temperatures of 900-1100°C. In addition, tensile properties were determined over the temperature range from -80 to 100°C. It was observed that in spite of the lower Al content, the austenitic steel possessed the hot deformation resistance about twice as high as that of the duplex steel. Whereas the flow stress curves of the austenitic steel exhibited work hardening followed by slight softening due to dynamic recrystallisation, the duplex steel showed the absence of work hardening and discontinuous yielding under similar conditions. Tensile tests at low temperatures revealed that the austenitic grade had a lower yield strength than that of the duplex grade, but much better ductility, the elongation increasing with decreasing temperature, contrary to that for the duplex steel. This can be attributed to the intense mechanical twinning in the austenitic steel, while in the duplex steel, twinning occurred in the ferrite only and the austenite showed dislocation glide.

Influence of Aging Time on the Tensile Strenght of a Duplex Stainless Steel

2014 ◽  
Vol 805 ◽  
pp. 210-214
Author(s):  
G.S. Machado ◽  
M.L.N.M. Melo ◽  
C.A. Rodrigues
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Sigma Phase ◽  
Tensile Tests ◽  
Heat Treated ◽  
Duplex Steel ◽  
Saf 2205 ◽  
Precipitation Phase ◽  
Tensile Test Data ◽  
Do So

This article was aimed at studying the influence of different aging times during the precipitation phase of the UNS S31803 (SAF 2205) duplex steel. To do so, all the test specimens were solution heat treated at 1050oC for 1 hour and quenched in water. After this step, the samples were aged at 850°C for periods of 10, 60 and 600 minutes and cooled in water. The aging heat treatments (TT) were performed in order to precipitate the sigma phase. Samples were subjected to microhardness and tensile tests so that the influence of the microstructural changes over the mechanical properties of the steel was assessed. Based on the microhardness and tensile test data, it was possible to verify a significant change over the mechanical properties of the UNS S31803 steel.

Sign in / Sign up

Export Citation Format

Share Document