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.

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.

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.

Effect of High Temperature on Wear Behavior of Stir Cast Aluminium/Boron Carbide Composites

2020 ◽  
Vol 22 (4) ◽  
pp. 1031-1046
Author(s):  
X. Canute ◽  
M. C. Majumder
Keyword(s):  
High Temperature ◽  
Wear Rate ◽  
Boron Carbide ◽  
Wear Behavior ◽  
Base Alloy ◽  
Weight Fraction ◽  
Sliding Velocity ◽  
Wear Properties ◽  
High Temperature Wear ◽  
The Matrix

AbstractThe need for development of high temperature wear resistant composite materials with superior mechanical properties and tribological properties is increasing significantly. The high temperature wear properties of aluminium boron carbide composites was evaluated in this investigation. The effect of load, sliding velocity, temperature and reinforcement percentage on wear rate was determined by the pin heating method using pin heating arrangement. The size and structure of base alloy particles change considerably with an increase of boron carbide particles. The wettability and interface bonding between the matrix and reinforcement enhanced by the addition of potassium flurotitanate. ANOVA technique was used to study the effect of input parameters on wear rate. The investigation reveals that the load had higher significance than sliding velocity, temperature and weight fraction. The pin surface was studied with a high-resolution scanning electron microscope. Regression analysis revealed an extensive association between control parameters and response. The developed composites can be used in the production of automobile parts requiring high wear, frictional and thermal resistance.

Mechanical characterization of LM25 alloy matrix composite reinforced with boron carbide

2021 ◽  
pp. 002199832110055
Author(s):  
Zeeshan Ahmad ◽  
Sabah Khan
Keyword(s):  
Tensile Strength ◽  
Boron Carbide ◽  
Mechanical Characterization ◽  
Stir Casting ◽  
Surface Mapping ◽  
Alloy Matrix ◽  
Casting Technique ◽  
The Matrix ◽  
Carbide Particles

Alumnium alloy LM 25 based composites reinforced with boron carbide at different weight fractions of 4%, 8%, and 12% were fabricated by stir casting technique. The microstructures and morphology of the fabricated composites were studied by scanning electron microscopy and energy dispersive spectroscopy. Elemental mapping of all fabricated composites were done to demonstrate the elements present in the matrix and fabricated composites. The results of microstructural analyses reveal homogenous dispersion of reinforcement particles in the matrix with some little amount of clustering found in composites reinforced with 12% wt. of boron carbide. The mechanical characterization is done for both alloy LM 25 and all fabricated composites based on hardness and tensile strength. The hardness increased from 13.6% to 21.31% and tensile strength 6.4% to 22.8% as reinforcement percentage of boron carbide particles increased from 0% to 12% wt. A fractured surface mapping was also done for all composites.

scholarly journals Comparison of Structure and Properties of Mo2FeB2-Based Cermets Prepared by Welding Metallurgy and Vacuum Sintering

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 46
Author(s):  
Hu Xu ◽  
Junsheng Sun ◽  
Jun Jin ◽  
Jijun Song ◽  
Chi Wang
Keyword(s):  
Wear Resistance ◽  
Corrosion Resistance ◽  
Volume Fraction ◽  
Phase Evolution ◽  
304 Stainless Steel ◽  
Vacuum Sintering ◽  
Cored Wire ◽  
Welding Metallurgy ◽  
Metallurgical Bonding ◽  
The Matrix

At present, most Mo2FeB2-based cermets are prepared by vacuum sintering. However, vacuum sintering is only suitable for ordinary cylinder and cuboid workpieces, and it is difficult to apply to large curved surface and large size workpieces. Therefore, in order to improve the flexibility of preparing Mo2FeB2 cermet, a flux cored wire with 70% filling rate, 304 stainless steel, 60 wt% Mo powder and 40 wt% FeB powder was prepared. Mo2FeB2 cermet was prepared by an arc cladding welding metallurgy method with flux cored wire. In this paper, the microstructure, phase evolution, hardness, wear resistance and corrosion resistance of Mo2FeB2 cermets prepared by the vacuum sintering (VM-Mo2FeB2) and arc cladding welding metallurgy method (WM-Mo2FeB2) were systematically studied. The results show that VM-Mo2FeB2 is composed of Mo2FeB2 and γ-CrFeNi.WM-Mo2FeB2 is composed of Mo2FeB2, NiCrFe, MoCrFe and Cr2B3. The volume fraction of hard phase in WM-Mo2FeB2 is lower than that of VM-Mo2FeB2, and its hardness and corrosion resistance are also slightly lower than that of VM-Mo2FeB2, but there are obvious pores in the microstructure of VM-Mo2FeB2, which affects its properties. The results show that WM-Mo2FeB2 has good diffusion and metallurgical bonding with the matrix and has no obvious pores. The microstructure is compact and the wear resistance is better than that of VM-Mo2FeB2.

scholarly journals Study on σ Phase in Fe–Al–Cr Alloys

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1092 ◽  
Author(s):  
Jintao Wang ◽  
Shouping Liu ◽  
Xiaoyu Han
Keyword(s):  
Mechanical Properties ◽  
Grain Boundaries ◽  
Grain Growth ◽  
Thermodynamic Calculation ◽  
Second Phase ◽  
Σ Phase ◽  
Austenitic Transformation ◽  
The Matrix ◽  
The Relationship

In this paper, a method of using the second phase to control the grain growth in Fe–Al–Cr alloys was proposed, in order to obtain better mechanical properties. In Fe–Al–Cr alloys, austenitic transformation occurs by adding austenitizing elements, leading to the formation of the second phase and segregation at the grain boundaries, which hinders grain growth. FeCr(σ) phase was obtained in the Fe–Al–Cr alloys, which had grains of several microns and was coherent and coplanar with the matrix (Fe2AlCr). The nucleation of σ phase in Fe–Al–Cr alloy was controlled by the ratio of nickel to chromium. When the Ni/Cr (eq) ratio of alloys was more than 0.19, σ phase could nucleate in Fe–Al–Cr alloy. The relationship between austenitizing and nucleation of FeCr(σ) phase was given by thermodynamic calculation.

Microstructures and Properties of Tungsten Carbide Particle-Reinforced Composites Fabricated by Overlaying Welding with Flux-Cored Wire

2011 ◽  
Vol 228-229 ◽  
pp. 548-551
Author(s):  
Lian Jie Li ◽  
Le Dai
Keyword(s):  
Wear Resistance ◽  
Tungsten Carbide ◽  
Carbide Particle ◽  
Reinforced Composites ◽  
Small Particles ◽  
Cored Wire ◽  
Steel Microstructure ◽  
Surface Iron ◽  
The Matrix ◽  
Surface Rigidity

The wire was made by Tungsten Carbide(WC) particles as core. MIG welding was used to surface iron-based WC wearable composite coating of different size and content of WC particles on mild steel. Microstructure was investigated. Surface rigidity and wear resistance were tested. The results indicate that the small particles are dissolved seriously, which separate out with reticulation. The hardness and wear resistance of the matrix are relative higher. The big particles are dissolved less, tree crystal separates out along particles. The particles are easy to fall off when wearing. So the hardness and wear resistance of the substrate are relative lower. The admixture with 80% big particles and 20% small particles has the best wear resistance, its wear resistance can achieve quintupling of quenching 45 steel. The hardness and wear resistance increase with content of WC increasing.

In SituHigh-Resolution Electron Spectroscopic Imaging and Real-Time Image Simulation of Precipitate Growth Mechanisms

1997 ◽  
Vol 3 (S2) ◽  
pp. 627-628
Author(s):  
J. M. Howe ◽  
M. M. Tsai ◽  
A. A. Csontos
Keyword(s):  
Atomic Level ◽  
Interface Motion ◽  
Bonding Structure ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Precipitate Growth ◽  
The Matrix ◽  
Interphase Boundaries ◽  
Transformation Mechanisms ◽  
Kinetics Of

Precipitate interfaces are ideal for studying the relationship between atomic bonding, structure and composition at internal interfaces and the mechanisms and kinetics of their motion as a function of temperature or driving force for reaction. The crystallography between coherent and semicoherent precipitates and the matrix is well-defined and the precipitate interfaces are often planar and grow by a terrace-ledge-kink mechanism, making them well-suited for study by conventional and high-resolution transmission electron microscopy (HRTEM).Motion of precipitate interfaces, or more generally, interphase boundaries, involves a change in lattice, composition or both. In order to understand the mechansims of interfacial motion, it is necessary to determine the structural and compositional changes that occur at the highest possible resolution, i.e., as close to the atomic level as possible, and also, to determine the corresponding kinetics of interface motion. HRTEM is an excellent technique for determining the atomic structure of transformation interfaces and in situhot-stage HRTEM is deal for determining interface dynamics at the atomic level, provided the transformation mechanisms are not altered by the thinness of the TEM foil.

scholarly journals Strong Interactions between Austenite and the Matrix of Medium-Mn Steel during Intercritical Annealing

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3366 ◽  
Author(s):  
Tianpeng Zhou ◽  
Cunyu Wang ◽  
Chang Wang ◽  
Wenquan Cao ◽  
Zejun Chen
Keyword(s):  
Grain Size ◽  
Annealing Temperature ◽  
Ferrite Matrix ◽  
Strong Interactions ◽  
Recrystallization Process ◽  
Austenite Grain Size ◽  
Recrystallization Kinetics ◽  
Average Grain Size ◽  
The Matrix ◽  
Austenite Grains

The effects of heat treatment on the microstructure evolution was studied in regards to austenite nucleation and grain growth. It was found that the austenite nucleation and matrix recrystallization kinetics of samples annealed at 675 °C for different times were revealed, implying a strong interaction between the ferrite matrix and austenite. The recrystallization of the matrix during annealing provided favorable conditions for austenite nucleation and growth, and the formation of austenite during this process reduced the matrix recrystallization kinetics, thus delaying the recrystallization process of the matrix around the austenite grains. The statistical results for the austenite grain size under different annealing temperatures indicated that the average grain size of the austenite slightly increases with increasing of the annealing temperature, but the austenite with the largest grain size grows faster at the same temperature. This difference is attributed to the strict Kurdjumov Sachs (KS) orientation relationship (OR) between the austenite grains and the matrix, because the growth of austenite with a strict KS OR with the matrix is often inhibited during annealing. In contrast, the austenite maintains a non-strict KS OR with the matrix and can grow preferentially with increasing annealing temperature and time.

Effect of Al and Ti Additions in Cast Nickel Base Alloy, Grade Hastelloy X by Arc Melting Process on Microstructures and Oxidation Behavior at 900°C and 1000°C

2014 ◽  
Vol 548-549 ◽  
pp. 274-279 ◽  
Author(s):  
Pajaree Srigiofun ◽  
Panyawat Wangyao ◽  
Gobboon Lothongkum ◽  
Ekasit Nisaratanaporn
Keyword(s):  
Oxidation Resistance ◽  
Base Alloy ◽  
Melting Process ◽  
Vacuum Arc ◽  
Nickel Base Alloy ◽  
Hastelloy X ◽  
Σ Phase ◽  
Arc Melting ◽  
The Matrix ◽  
Nickel Base

The nickel base alloy, grade Hastelloy X was modified by Aluminum and Titanium additions by means of vacuum arc melting process in order to improve microstructural characteristics and oxidation resistance. The arc melted Hastelloy X was added Aluminum and Titanium each for 2%, 4% and 6% by weight. Then all specimens were performed with heat treatment, which consists of solutioning treatment at 1125°C for 24 hours and precipitation aging at temperatures of 760°C, 800°C and 845°C for 24 hours. Both aluminum and titanium additions resulted in network intermetalic phase formation, namely, σ-phase, throughout the matrix. Furthermore, the addition of both elements provided the better oxidation resistance for the alloys.

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