The Effect of Co and Cu on the Creep Properties of High Chromium (12%Cr) Ferritic Steel

2011 ◽  
Vol 311-313 ◽  
pp. 944-947
Author(s):  
Xi Xun Shen ◽  
Jun Liang Liu ◽  
Zhou Xu
Keyword(s):  
Ferritic Steel ◽  
Fracture Behavior ◽  
Prior Austenite ◽  
Ferritic Steels ◽  
Creep Properties ◽  
High Chromium ◽  
Δ Ferrite ◽  
Fracture Behaviors ◽  
The Matrix ◽  
Austenite Grains

In this paper, three kinds of 12% Cr ferritic steels without Co and Cu, with 3%Co and with 3%Cu are produced. The addition Co and Cu lead to an evident increase in creep-resistant of the ferritic steel, and furthermore also markedly affect the fracture behavior. Microstructures were studied by comparing three kinds of the 12% ferritic steels to better understand different in those creep behaviors and fracture behaviors. It was found that the addition of Co and Cu not only inhibit the formation δ-ferrite but also are benefit for the growth of prior austenite grains. Additionally, the part of the added Cu precipitates in the matrix of the ferritic steel. These changes in microstructure and the solution of Co and Cu strengthen the ferritic steel.

Evaluation of Al-Hf Coating on Ferritic Steels by CVD-FBR Technology in Steam Oxidation

2008 ◽  
Vol 595-598 ◽  
pp. 359-366
Author(s):  
F.J. Bolívar ◽  
L. Sánchez ◽  
M.P. Hierro ◽  
J.A. Trilleros ◽  
F.J. Pérez
Keyword(s):  
Atmospheric Pressure ◽  
Electron Probe ◽  
Ferritic Steel ◽  
Power Plants ◽  
Protective Coatings ◽  
Steam Oxidation ◽  
Ferritic Steels ◽  
Steam Turbines ◽  
Creep Properties ◽  
Good Oxidation Resistance

The steels with chromium contents between 9 and 12%wt are used for power plants with advanced steam conditions. These steels possess good creep properties similar to the 9% Cr steels as well as good creep and good oxidation resistance at temperatures between 500-600°C. In the last years efforts have been made to develop coatings for protection against oxidation in order to allow operation of steam turbines at 650°C. In this study, Al-Hf protective coatings were deposited by CVD-FBR on the ferritic steel HCM-12A followed by a diffusion heat treatment, and were shown to be protective at 650°C under steam for at least 3000 hours of laboratory steam exposure under atmospheric pressure. The morphology and composition of the coatings were characterized by techniques, including scanning electron microscopy (SEM), electron probe microanalysis, and Xray diffraction (XRD). The results showed a substantial increase of steam oxidation protection afforded by Al-Hf coating deposited by the CVD-FBR process.

Formation of the Fe2Hf Laves Phase through Eutectoid Type Reaction of δ→γ+Fe2Hf in Ferritic Heat Resistant Steels

2015 ◽  
Vol 1760 ◽  
Author(s):  
Satoru Kobayashi
Keyword(s):  
Phase Transformation ◽  
Ferritic Steel ◽  
Laves Phase ◽  
Ferritic Steels ◽  
Microstructural Observation ◽  
Interphase Precipitation ◽  
Δ Ferrite ◽  
Term Creep ◽  
Heat Resistant Steels

ABSTRACTPeriodically arrayed rows of fine Fe2Hf Laves phase particles were found to form in 9Cr ferritic steel. Microstructural observation demonstrates that the particles were formed on cooling through the interphase precipitation on the phase transformation from the δ ferrite to the γ austenite along the eutectoid transformation route of δ → γ+Fe2Hf and subsequently a phase transformation from the austenite to the α ferrite took place. This eutectoid route is expected to be effectively used for improving the long term creep strength of ferritic steels with Laves phase.

Creep Properties of High Cr Resisting Weld Metal Alloyed with Co

2010 ◽  
Vol 148-149 ◽  
pp. 1562-1566
Author(s):  
Xue Wang ◽  
Qian Gang Pan ◽  
Liang Fei Zhan ◽  
Zi Jun Liu ◽  
Hong Liu ◽  
...  
Keyword(s):  
Weld Metal ◽  
Arc Welding ◽  
Ferritic Steel ◽  
Submerged Arc Welding ◽  
Steel Weld ◽  
Martensitic Structure ◽  
Creep Properties ◽  
Steel Weld Metal ◽  
Δ Ferrite ◽  
Submerged Arc

A 9-12% Cr ferritic steel weld metal containing 1% Co partially substituted for nickel was prepared by submerged arc welding processing(SAW). The microstructures and creep properties of the weld metal have been investigated. The microstructure exhibited a fully tempered martensitic structure free of δ-ferrite. The creep properties of the obtained weld metal are inferior to that of the P92 base metal at 600 and 650 . The values of A and n for weld metal in Norton power law constitution at 650 are 1.12×10-21 and 8.14, respectively.

Structure and Characteristics of the Metal of the Cr-Ni-Mo-Mn-Si-Ti-Nb System Obtained by Surfacing with a Flux-Cored Wire Alloyed by Boron Carbide

2019 ◽  
Vol 946 ◽  
pp. 91-96 ◽  
Author(s):  
E.N. Eremin ◽  
A.S. Losev ◽  
S.A. Borodikhin
Keyword(s):  
Boron Carbide ◽  
Cored Wire ◽  
Stop Valve ◽  
Σ Phase ◽  
Δ Ferrite ◽  
Deposited Metal ◽  
The Matrix ◽  
Interphase Boundaries ◽  
Austenite Grains ◽  
B Doping

This study explores structure and characteristics of the nickel-chrome steel of the Cr-Ni-Mo-Mn-Si-Ti-Nb-B doping system obtained by surfacing with a flux-cored wire alloyed by boron carbide. It has shown that the deposited metal has a composite structure consisting of a supersaturated with alloyed elements solid solution with an austenite-martensitic matrix and a eutectic component (Mo, Cr, Fe, Nb)2B in the form of sections along the boundaries of former austenite grains. Because of the significant content of ferrite-forming elements in the process of crystallization, a metastable δ-ferrite is formed in the weld metal in the form of differently oriented interlayers between the martensite rails. As a result of aging of such a deposited metal at 500 °C for 2 hours, the metastable ferrite undergoes decay at the interphase boundaries α/δ with the formation of the σ phase, which represents sharpened plates with the size of 300÷550 nm. Moreover, aging leads to hardening of the matrix by finely dispersed carboboride and intermetallic phases (Cr, Mo, Fe, Nb, Ti)23(С,В)6, (Fe, Cr, Si)2(Mo, Ti) и (Ni, Fe)3Ti, causing high levels of hardness and wear resistance. The usage of this wire as a surfacing material allows to increase significantly the operability and reliability of the stop valve parts, which work on abrasion in contact with corrosive medium.

scholarly journals Effect of the Thermo-Mechanical Processing on the Impact Toughness of a 12% Cr Martensitic Steel with Co, Cu, W, Mo and Ta Doping

Metals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 3
Author(s):  
Alexandra Fedoseeva ◽  
Ivan Nikitin ◽  
Nadezhda Dudova ◽  
John Hald ◽  
Rustam Kaibyshev
Keyword(s):  
Impact Toughness ◽  
Prior Austenite ◽  
Hot Forging ◽  
Mechanical Processing ◽  
Δ Ferrite ◽  
Conventional Heat Treatment ◽  
Austenite Grains ◽  
The Impact ◽  
M23c6 Carbides

This paper presents the results of an experimental investigation of a 12% Cr steel where a significant increase in Charpy impact toughness and a slight decrease in ductile-brittle transition temperature (DBTT) from 70 °C to 65 °C were obtained through thermo-mechanical processing, including interim hot forging at 1050 °C with long-term annealing at 1000 °C, as compared with conventional heat treatment. At lower temperatures ranging from −20 °C to 25 °C, the value of impact toughness comprised ~40 J cm−2 in the present 12% Cr steel subjected to thermo-mechanical processing. The amount of δ-ferrite decreased to 3.8%, whereas the size of prior austenite grains did not change and comprised about 40–50 μm. The boundaries between δ-ferrite and martensitic laths were decorated by continuous chains of Cr- and W-rich carbides. M23C6 carbides also precipitated along the boundaries of prior austenite grains, packets, blocks and martensitic laths. Thermo-mechanical processing increased the mean size of M23C6 carbides and decreased their number particle densities along the lath boundaries. Moreover, the precipitation of a high number of non-equilibrium V-rich MX particles was induced by hot forging and long-term normalizing at 1000 °C for 24 h.

Effect of Heat Treatment on the Microstructure and Hardness f X38CrMo16 Steel

2013 ◽  
Vol 455 ◽  
pp. 179-184
Author(s):  
Meng Wu ◽  
Yan Ping Zeng ◽  
Wen Yang
Keyword(s):  
Intermetallic Phase ◽  
Xrd Analysis ◽  
Quenching Temperature ◽  
Hardness Tester ◽  
Secondary Particles ◽  
Δ Ferrite ◽  
The Matrix ◽  
Austenite Grains ◽  
Quenched Steel ◽  
Quenched And Tempered Steel

Effect of quenching-tempering process on microstructure and hardness of X38CrMo16 steel was investigated by means of OM, SEM, XRD and a digital hardness tester. The quenched and tempered steel consists of martensite (or its tempered structure), δ-ferrite and secondary particles. The secondary particles are identified as a FeCr intermetallic phase based on EDS and XRD analysis. Along with the increase of quenching temperature, the quantity of secondary particles gradually decreases and the prior austenite grains grow significantly, which led to the coarsening of martensite. A large number of blocky ferrite formed due to the increase of chromium level in the matrix. In addition, the hardness of the quenched steel continuously increases with quenching temperature up to 1100°C and then drop observably. Hence, the suitable quenching temperature of the steel is between 1050 and 1100°C. After tempering at 200 and 300°C, the hardness of the steel decreased due to the formation of tempered martensite and increased slightly after tempering at 400°C owing to secondary hardening, whereas this value decreased again after tempering at 500 and 600°C due to the formation of tempered sorbite.

Microanalysis of precipitates in a ferritic steel

1978 ◽  
Vol 36 (1) ◽  
pp. 618-619
Author(s):  
J.M. Titchmarsh
Keyword(s):  
Ferritic Steel ◽  
Particle Identification ◽  
Energy Dispersive ◽  
Objective Lens ◽  
Ferritic Steels ◽  
Replica Technique ◽  
X Ray ◽  
Large Numbers ◽  
Scanning Transmission ◽  
Made In

The advances in recent years in the microanalytical capabilities of conventional TEM's fitted with probe forming lenses allow much more detailed investigations to be made of the microstructures of complex alloys, such as ferritic steels, than have been possible previously. In particular, the identification of individual precipitate particles with dimensions of a few tens of nanometers in alloys containing high densities of several chemically and crystallographically different precipitate types is feasible. The aim of the investigation described in this paper was to establish a method which allowed individual particle identification to be made in a few seconds so that large numbers of particles could be examined in a few hours.A Philips EM400 microscope, fitted with the scanning transmission (STEM) objective lens pole-pieces and an EDAX energy dispersive X-ray analyser, was used at 120 kV with a thermal W hairpin filament. The precipitates examined were extracted using a standard C replica technique from specimens of a 2¼Cr-lMo ferritic steel in a quenched and tempered condition.

scholarly journals Efficient Improvement in Fracture Toughness of Laminated Composite by Interleaving Functionalized Nanofibers

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2509
Author(s):  
Seyed Mohammad Javad Razavi ◽  
Rasoul Esmaeely Neisiany ◽  
Moe Razavi ◽  
Afsaneh Fakhar ◽  
Vigneshwaran Shanmugam ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Fracture Behavior ◽  
Laminated Composite ◽  
Carbon Phase ◽  
Reinforced Composite ◽  
Reinforcing Agent ◽  
The Matrix ◽  
As Stress ◽  
Double Cantilever Beam Test ◽  
Pan Nanofiber

Functionalized polyacrylonitrile (PAN) nanofibers were used in the present investigation to enhance the fracture behavior of carbon epoxy composite in order to prevent delamination if any crack propagates in the resin rich area. The main intent of this investigation was to analyze the efficiency of PAN nanofiber as a reinforcing agent for the carbon fiber-based epoxy structural composite. The composites were fabricated with stacked unidirectional carbon fibers and the PAN powder was functionalized with glycidyl methacrylate (GMA) and then used as reinforcement. The fabricated composites’ fracture behavior was analyzed through a double cantilever beam test and the energy release rate of the composites was investigated. The neat PAN and functionalized PAN-reinforced samples had an 18% and a 50% increase in fracture energy, respectively, compared to the control composite. In addition, the samples reinforced with functionalized PAN nanofibers had 27% higher interlaminar strength compared to neat PAN-reinforced composite, implying more efficient stress transformation as well as stress distribution from the matrix phase (resin-rich area) to the reinforcement phase (carbon/phase) of the composites. The enhancement of fracture toughness provides an opportunity to alleviate the prevalent issues in laminated composites for structural operations and facilitate their adoption in industries for critical applications.

Sign in / Sign up

Export Citation Format

Share Document