Effect of quenching media on microstructural evolution, mechanical and wear properties of AISI4135 steel

Author(s):  
Praveen Singh ◽  
Satnam Singh

The aim of this work is to study the effect of various quenching media on the microstructural evolution and properties enhancement of AISI 4135 alloy steel. The formation of dual microstructures and their effect on mechanical and wear properties are investigated in this work. An attempt is made to correlate the microstructure-properties relation based on the quenching method used. Steel is heated above the austenitic temperatures (A3) and subsequently cooled down through various quenching media to obtain the variations in microstructures and related properties. The heat treated samples were investigated for microstructural evolution through optical microscopy and scanning electron microscope; mechanical characterization through microhardness study, tensile testing and impact testing; and wear characterization through pin on disc tribometer. It was observed that increased cooling rates increased the volume fraction of martensitic structures whereas oil quenching enhanced fine pearlite and bainite formation. The air cooling led to the formation of fine pearlite along with ferrite structures. Strength, hardness and wear resistance is favored with martensite formation but toughness decreases.

2005 ◽  
Vol 475-479 ◽  
pp. 81-84
Author(s):  
Sung Kang Hur ◽  
Kee Sam Shin ◽  
Jung Hoon Yoo ◽  
Ja Min Koo ◽  
Soo Lee ◽  
...  

The evolution of microstructure and its effects on the mechanical properties of modified 9%Cr-1%Mo steel during heat-treating at 1050°C for 15 min and then isothermal heat treatment at 380~760°C with subsequent air-cooling have been investigated. For the microstructural and mechanical property analyses, OM, SEM, EDS, XRD, hardness and impact tests were used. In accordance with the severity of the heat-treatment, the microstructure evolved from the untransformed martensite to the partially transformed dual phases of martensite and ferrite, and then fully transformed to ferrite. Impact values at ambient temperature for specimens isothermally heat-treated at 320 - 380°C, predominantly at about 350°C were lower than others’ with similar martensitic structure. The partially transformed specimens with dual phases of martensite and ferrite also showed lower impact values than samples with untransformed with martensitic, and transformed with ferritic structures.


2016 ◽  
Vol 04 (04) ◽  
pp. 1640013 ◽  
Author(s):  
Santanu Duari ◽  
Arkadeb Mukhopadhyay ◽  
Tapan Kr. Barman ◽  
Prasanta Sahoo

This study presents the deposition and tribological characterization of electroless Ni–P–Cu coatings deposited on AISI 1040 steel specimens. After deposition, coatings are heat treated at 500[Formula: see text]C for 1[Formula: see text]h. Surface morphology study of the coatings reveals its typical cauliflower like appearance. Composition study of the coatings using energy dispersive X-ray analysis indicates that the deposit lies in the high phosphorus range. The coatings undergo crystallization on heat treatment. A significant improvement in microhardness of the coatings is also observed on heat treatment due to the precipitation of hard crystalline phases. The heat-treated coatings are subjected to sliding wear tests on a pin-on-disc type tribo-tester under dry condition by varying the applied normal load, sliding speed and sliding duration. The coefficient of friction (COF) increases with an increase in the applied normal load while it decreases with an increase in the sliding speed. The wear depth on the other hand increases with an increase in applied normal load as well as sliding speed. The worn surface morphology mainly indicates fracture of the nodules.


Author(s):  
João Paulo Gomes Antunes Costa ◽  
Miguel Justino Ribeiro Barboza ◽  
Helio Goldenstein ◽  
André Luiz Vasconcellos da Costa e Silva ◽  
Carlos Angelo Nunes

Abstract Boron-added steel has been used in several automotive components in which the energy absorbed in impact testing is an important requirement. Previous thermodynamic studies have shown that boron addition promotes significant change in equilibrium phases, increasing the volume fraction of precipitated phases, mostly due to increased carbide stability and formation of borocarbides. As volume fraction, size and distribution of precipitates influence the absorbed energy in impact testing of steels, it is important to study M23(B,C)6 borocarbide precipitation and coarsening kinetics and its effects on Charpy V-notch absorbed energy of boron steels. In the present work, borocarbide coarsening kinetics were evaluated using optical microscopy in samples heat-treated at 880 0C for different times. The borocarbide coarsening kinetics data suggest that growth is controlled by an interfacial reaction mechanism. The Charpy V-notch absorbed energy decreases with increasing borocarbide section size and the embrittlement was successfully described by an empirical equation.


2015 ◽  
Vol 48 (1) ◽  
pp. 52-60 ◽  
Author(s):  
Prakash Srirangam ◽  
Yasir Idrees ◽  
Jan Ilavsky ◽  
Mark R. Daymond

The ultra-small-angle X-ray scattering (USAXS) technique has been used to investigate and to quantify the morphology and size distribution of second-phase particles in Zircaloy-4 under various heat-treatment conditions. The alloy samples were solutionized in the β phase field at 1293 K for 15 min and then cooled at different rates, including water quenching, air cooling and furnace cooling. The water-quenched samples were subsequently subjected to a thermal aging treatment at 873 K for different aging times (30, 60, 120 and 300 min). The USAXS results show that water quenching and air cooling from the β phase field produces a narrow size distribution of fine-size precipitates with an average diameter of 300–800 Å, while furnace cooling resulted in coarsening of the particles, with a broad size distribution having an average precipitate size of 600–1200 Å. Further, the furnace-cooled sample shows a higher volume fraction of particles than the water-quenched or air-cooled sample. The USAXS results on the quenched then aged samples show that aging at 873 K for 10 min resulted in very fine size precipitates with an average diameter of 200–350 Å. A rapid precipitation with the highest number density of second-phase particles amongst all the heat-treated samples (4.3 × 1020 m−3) was observed in the sample aged for 10 min at 873 K. Particles of larger size and with a broad size distribution were observed in the sample aged at 873 K for 300 min. A bimodal type of particle size distribution was observed in all the heat-treated samples. Important parameters in the characterization of second-phase particles, such as the average size, size distribution, volume fraction and number density, were evaluated and quantified. These parameters are discussed for both β heat-treated and aged specimens. Transmission and scanning transmission electron microscopy characterization were carried out on all heat-treated samples, to assist in interpretation and to substantiate the results from the USAXS measurements.


2014 ◽  
Vol 217-218 ◽  
pp. 111-118
Author(s):  
Shu Sen Wu ◽  
Chong Lin ◽  
Shu Lin Lü ◽  
Ping An

The Fe-rich Al-Si alloys have the potential to be used to make wear-resistant parts. However, there has been few work devoted to study the wear behavior of the hypereutectic Al-Si alloys with about 2% Fe (mass %). In this work, the semi-solid slurry of the alloy was prepared by an ultrasonic vibration (USV) process. The effect of Fe content on dry sliding wear properties of the alloys rheo-casted after USV treatment was investigated. The wear tests were carried out using a pin-on-disc wear tester at four different loads of 50N, 100N, 150N and 200N at a constant sliding speed of 0.75m/s. The results show that the wear rate of USV treated alloy increases almost linearly as the applied load increases from 50 N to 200N. The alloys made with semi-solid process exhibited improved wear resistance at the entire applied load range in comparison to the conventional casting alloys. At the applied load of 50N, oxidative wear is the dominant mechanism for the alloys with USV treatment. At 200N, a combination of delamination and oxidation wear is the main wear mechanism. The wear resistance of Al-17Si alloys containing 2% to 3% Fe is closely related to the morphology, size and volume fraction of Fe-bearing compounds, which can be changed by USV semi-solid process.


Author(s):  
W. T. Donlon ◽  
S. Shinozaki ◽  
E. M. Logothetis ◽  
W. Kaizer

Since point defects have a limited solubility in the rutile (TiO2) lattice, small deviations from stoichiometry are known to produce crystallographic shear (CS) planes which accomodate local variations in composition. The material used in this study was porous polycrystalline TiO2 (60% dense), in the form of 3mm. diameter disks, 1mm thick. Samples were mechanically polished, ion-milled by conventional techniques, and initially examined with the use of a Siemens EM102. The electron transparent thin foils were then heat-treated under controlled atmospheres of CO/CO2 and H2 and reexamined in the same manner.The “as-received” material contained mostly TiO2 grains (∼5μm diameter) which had no extended defects. Several grains however, aid exhibit a structure similar to micro-twinned grains observed in reduced rutile. Lattice fringe images (Fig. 1) of these grains reveal that the adjoining layers are not simply twin related variants of a single TinO2n-1 compound. Rather these layers (100 - 250 Å wide) are alternately comprised of stoichiometric TiO2 (rutile) and reduced TiO2 in the form of Ti8O15, with the Ti8O15 layers on either side of the TiO2 being twin related.


Author(s):  
Michael M. Kersker ◽  
E. A. Aigeltinger ◽  
J. J. IIren

Ni-rich alloys based on approximate ternary composition Ni-8Mo-15A1 (at%) are presently under investigation in an attempt to study the contribution, if any, of the profusion of Mo-rich NixMo metastable compounds that these alloys contain to their excellent mechanical properties. One of the alloys containing metastable NixMo precipitates is RSR 197 of composition Ni-8.96Mo-15.06A1-1.98Ta-.015Yt. The alloy was prepared at Pratt and Whitney Government Products Division, West Palm Beach, Florida, from rapidly solidified powder. The powder was canned under inert conditions and extruded as rod at 1315°C. The as-extruded rod, after air cooling, was solution treated at 1315°C for two hours, air cooled, and heat treated for one hour at 815°C, followed again by air cooling.


Author(s):  
H. Sh. Hammood ◽  
S. S. Irhayyim ◽  
A. Y. Awad ◽  
H. A. Abdulhadi

Multiwall Carbon nanotubes (MWCNTs) are frequently attractive due to their novel physical and chemical characteristics, as well as their larger aspect ratio and higher conductivity. Therefore, MWCNTs can allow tremendous possibilities for the improvement of the necessarily unique composite materials system. The present work deals with the fabrication of Cu-Fe/CNTs hybrid composites manufactured by powder metallurgy techniques. Copper powder with 10 vol. % of iron powder and different volume fractions of Multi-Wall Carbon Nanotubes (MWCNTs) were mixed to get hybrid composites. The hybrid composites were fabricated by adding 0.3, 0.6, 0.9, and 1.2 vol.% of MWCNTs to Cu- 10% Fe mixture using a mechanical mixer. The samples were compressed under a load of 700 MPa using a hydraulic press to compact the samples. Sintering was done at 900°C for 2 h at 5ºC/min heating rate. The microscopic structure was studied using a Scanning Electron Microscope (SEM). The effect of CNTs on the mechanical and wear properties, such as micro-hardness, dry sliding wear, density, and porosity were studied in detail. The wear tests were carried out at a fixed time of 20 minutes while the applied loads were varied (5, 10, 15, and 20 N). SEM images revealed that CNTs were uniformly distributed with relative agglomeration within the Cu/Fe matrix. The results showed that the hardness, density, and wear rates decreased while the percentage of porosity increased with increasing the CNT volume fraction. Furthermore, the wear rate for all the CNTs contents increased with the applied load.


MRS Advances ◽  
2020 ◽  
Vol 5 (59-60) ◽  
pp. 3077-3089
Author(s):  
Alexeis Sánchez ◽  
Arnoldo Bedolla-Jacuinde ◽  
Francisco V. Guerra ◽  
I. Mejía

AbstractFrom the present study, vanadium additions up to 6.4% were added to a 14%Cr-3%C white iron, and the effect on the microstructure, hardness and abrasive wear were analysed. The experimental irons were melted in an open induction furnace and cast into sand moulds to obtain bars of 18, 25, and 37 mm thickness. The alloys were characterized by optical and electronic microscopy, and X-ray diffraction. Bulk hardness was measured in the as-cast conditions and after a destabilization heat treatment at 900°C for 45 min. Abrasive wear resistance tests were undertaken for the different irons according to the ASTM G65 standard in both as-cast and heat-treated conditions under a load of 60 N for 1500 m. The results show that, vanadium additions caused a decrease in the carbon content in the alloy and that some carbon is also consumed by forming primary vanadium carbides; thus, decreasing the eutectic M7C3 carbide volume fraction (CVF) from 30% for the base iron to 20% for the iron with 6.4%V;but overall CVF content (M7C3 + VC) is constant at 30%. Wear behaviour was better for the heat-treated alloys and mainly for the 6.4%V iron. Such a behaviour is discussed in terms of the CVF, the amount of vanadium carbides, the amount of martensite/austenite in matrix and the amount of secondary carbides precipitated during the destabilization heat treatment.


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