Journal articles: 'Carbides Effect of high temperatures on'

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Jiang, Zheng Yi, Xing Jian Gao, Dong Bin Wei, Sheng Li Li, Hong Mei Zhang, Jian Zhong Xu, Di Wu, and Si Hai Jiao. "Effect of Carbide Orientation on Sliding Wear Behaviour of High Chromium Cast Iron." Advanced Materials Research 1136 (January 2016): 567–72. http://dx.doi.org/10.4028/www.scientific.net/amr.1136.567.

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The effect of carbide orientation on the dry sliding wear behaviour of high chromium cast iron was studied by pin-on-disc type wear tests at room temperature. The carbide anisotropy was achieved by thermomechanical treatments at temperatures of 950 and 1150 °C. By cladding with low carbon steel, the brittle high chromium cast iron was hot compressed severely with crack free. The thermomechanical treatments not only change the carbide orientation, but also increase the volume fraction of carbides. Due to the long axis of carbide rods is parallel to the wear surface, the high chromium cast iron treated at 1150 °C has a superior wear resistance than the as-cast one, in which the long axis of carbides is perpendicular to the wear surface. For the high chromium cast iron treated at 950 °C, high volume fraction of carbide pits accelerates the wear rate significantly even though it has a similar carbide orientation as the sample treated at 1150 °C. The observations on wear tracks reveal that the ferrous matrix can be protected better from abrasion when the high chromium cast iron was treated at 1150 °C.

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Liu, Bowen, Tian Qin, Wei Xu, Chengchang Jia, Qiuchi Wu, Mingying Chen, and Zhe Liu. "Effect of Tempering Conditions on Secondary Hardening of Carbides and Retained Austenite in Spray-Formed M42 High-Speed Steel." Materials 12, no. 22 (November 11, 2019): 3714. http://dx.doi.org/10.3390/ma12223714.

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In this study, the effect of tempering conditions on microstructure, grain size, and carbide phase compositions of spray-formed high-speed steel after quenching at 1180 °C was studied. The influence of carbide phase, size of carbides, and retained austenite content on secondary hardening of the steel was analyzed by field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), electron backscattered diffraction (EBSD), and differential scanning calorimetry (DSC); the hardness, microhardness of carbide, and bending strength were tested. The results show that M3C, M6C, M7C3, and MC carbides may precipitate at different tempering temperatures and the transformation of the retained austenite can be controlled by tempering. The phase composition of carbides, microstructure, and retained austenite content strongly influences the performance characteristics of M42 high-speed steel after tempering. In contrast, the secondary carbides produced by tempering thrice at 540 °C are mainly M6C carbides rich in W and Mo elements, and the content of retained austenite is effectively reduced. At this stage, the Rockwell hardness reaches 67.2 HRC, bending strength reaches 3115 MPa, and the properties and microstructure are optimal.

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Pan, Yongliang, Tounan Jin, Naibo Yuan, Tiejun Ma, and Hanguang Fu. "Effect of austenitizing temperature on microstructure and properties of a high-speed cobalt steel." Materials Testing 64, no. 8 (August 1, 2022): 1122–35. http://dx.doi.org/10.1515/mt-2021-2187.

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Abstract The effect of different austenitizing temperatures on the type, morphology, distribution of carbides and martensite content in cobalt high-speed steel is characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction and energy dispersive spectrometry. The results show that the eutectic MC carbides hardly dissolve during austenitizing process, and the lamellar M2C carbides decompose into MC and M6C carbides at 1100 °C. A large amount of M23C6 carbides uniformly distributed on the matrix are dissolved into austenite at 1100 °C. With the increase of austenitizing temperature, alloy element dissolves into matrix and the effect of solid solution strengthening of martensite enhances, which increases the hardness of cobalt high-speed steel. However, when the austenitizing temperature exceeds 1050 °C, the excess alloying elements in the matrix reduce the Ms point and increase the volume fraction of retained austenite, resulting in decrease of hardness of cobalt high-speed steel. The peak hardness with 66.4 HRC appears when the austenitizing temperature reaches 1050 °C.

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Dudko, Valeriy, Diana Yuzbekova, Sergey Gaidar, Sofia Vetrova, and Rustam Kaibyshev. "Tempering Behavior of Novel Low-Alloy High-Strength Steel." Metals 12, no. 12 (December 17, 2022): 2177. http://dx.doi.org/10.3390/met12122177.

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The effect of tempering on the mechanical properties, structure, and dispersion of secondary phase particles is studied in 0.4%C-2%Si-1%Cr-1%Mo-VNb steel. This steel austenitized at 900 °C with subsequent water quenching exhibits a yield stress of 1445 MPa and a lath martensite structure with MX particles of ~40 nm located in matrix and boundary M6C carbides of ~210 nm. Tempering in the temperature interval of 200–400 °C provides a yield stress of 1625 MPa due to the precipitation of ε-carbide and cementite within laths. The yield stress decreases to 1415 and 1310 MPa after tempering at 500 and 650 °C, respectively, due to the replacement of matrix carbides by boundary M23C6 carbide. A Charpy V-notch impact energy of ~12 J/cm2 is almost independent from tempering temperatures of up to 400 °C and increases up to ~33 J/cm2 after tempering at 650 °C due to decreased yield stresses and increased plasticity.

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Hu, Qipeng, Miaohui Wang, Yunbo Chen, Hailong Liu, and Zhen Si. "The Effect of MC-Type Carbides on the Microstructure and Wear Behavior of S390 High-Speed Steel Produced via Spark Plasma Sintering." Metals 12, no. 12 (December 16, 2022): 2168. http://dx.doi.org/10.3390/met12122168.

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The microstructure and wear behavior of S390 high-speed steel (HSS) reinforced with different volume fractions of MC-type carbides produced via spark plasma sintering were investigated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) in this study. SEM and TEM results show that V-W-rich carbides are formed around the added MC-type carbides, and these carbides have a similar composition to the M(C, N) carbides precipitated at high temperatures according to thermodynamic calculations. Both macrohardness and three-point bending results show that the carbide type is the dominant factor increasing the hardness, and the volume fraction of the carbide is the dominant factor leading to a decrease in the three-point bending strength. The wear mechanism of HSS metal matrix composites (MMCs) is confirmed as abrasive wear and oxidative wear via wear tracks and oxidation films. Compared with the sample without reinforcement (85 HRA, wear coefficient of 1.50 × 10−15 m2/N), the best MT-3 sample exhibits a hardness increase of 1.8 HRA and a three-fold increase in wear resistance.

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Romanenko, Dmitriy N., Victor V. Gorozhankin, and Marina V. Nalimova. "Hardenability and Wear Resistance of Carburized to Hypereutectic Concentrations Steels." Solid State Phenomena 299 (January 2020): 330–34. http://dx.doi.org/10.4028/www.scientific.net/ssp.299.330.

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In this article the experimental data of the hardness and wear resistance of chrome-manganese steels 35H3G2F and 35HGF, which are cemented in a highly active paste-like carburizer and hardened at various temperatures, are presented. Cementation and high temperature carbonitriding of these steels leads to a high content of the carbide phase in the diffuse layers and an increase of hardness and wear resistance. The effect of carbides on the hardenability of diffuse layers are investigated. The hardening temperature ranges of these steels and the effect of alloying elements on hardness are established. The mechanism of the phase formation of the highest hardness structures is described. The carbides influence on the wear mechanism of cemented in various modes steels is studied.

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Cheng, Xiaole, Dong Zhang, Xiaojun Wu, Guangshen Xu, and Hanguang Fu. "Effect of quenching temperature on microstructure and properties of low silicon hypereutectic high chromium cast iron." Metallurgical Research & Technology 120, no. 1 (December 9, 2022): 102. http://dx.doi.org/10.1051/metal/2022105.

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In this paper, the effects of different quenching temperatures on the microstructure and properties of Fe–4.0C–35.0Cr–0.5Si (wt.%) low-silicon hypereutectic high-chromium cast iron (LS-HHCCI) was investigated. The effect of quenching temperature on the microstructure of LS-HHCCI was analyzed by optical microscope, scanning electron microscope, and X-ray diffractometer. After quenching at different temperatures, the hardness and wear resistance of LS-HHCCI were tested by Rockwell hardness tester, microhardness tester, and wear testing machine. The results show that the microstructure of as-cast LS-HHCCI is mainly composed of austenite matrix and M7C3 carbides. After quenching, the austenite matrix is transformed into martensite, and M23C6 type secondary carbides are precipitated in the matrix. As the quenching temperature increased from 950 °C to 1100 °C, the eutectic carbides first appeared as fine needles, and then they gather and grow up, showing elongated or lumpy. The hardness and abrasion resistance first increase and then decrease, it reached peak values of 67.2 HRC at the temperature of 1050 °C, while the wear resistance is the best.

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Tóth, László, and Réka Fábián. "The Effects of Quenching and Tempering Treatment on the Hardness and Microstructures of a Cold Work Steel." International Journal of Engineering and Management Sciences 4, no. 1 (March 3, 2019): 286–94. http://dx.doi.org/10.21791/ijems.2019.1.36.

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The X153CrMoV12 ledeburitic chromium steel characteristically has high abrasive wear resistance, due to their high carbon and high chromium contents with a large volume of carbides in the microstructure. This steel quality has high compression strength, excellent deep hardenability and toughness properties, dimensional stability during heat treatment, high resistance to softening at elevated temperatures. The higher hardness of cryogenic treated samples in comparison with conventional quenched samples mean lower quantity of retained austenite as at samples quenched to room temperature and tempered in similar condition. In the microstructure of samples were observed that the primary carbide did not dissolve at 1070°C and their net structure have not been changed during to heat treatment. During to tempering at high temperature the primary carbides have become more and more rounded. After low tempering temperature in martensite were observed some small rounded carbides also, increasing the tempering temperature the quantity of finely dispersed carbides increased, which result higher hardness. The important issues in heat treatment of this steels are the reduction or elimination of retained austenite due to cryogenic treatment.

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Li, Shaoying, Xiaojun Xi, Yiwa Luo, Mingtao Mao, Xiao Shi, Jing Guo, and Hanjie Guo. "Carbide Precipitation during Tempering and Its Effect on the Wear Loss of a High-Carbon 8 Mass% Cr Tool Steel." Materials 11, no. 12 (December 7, 2018): 2491. http://dx.doi.org/10.3390/ma11122491.

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In this paper, the precipitation of carbide and wear loss of high-carbon 8 mass% Cr tool steel at two tempering conditions (i.e., 773–803 K and 823–853 K) were studied by INCA Steel, EPMA-1720H, XRD, and ML-10 tester. The results show that the particles of test steels include the carbides (Cr7C3 and Cr23C6) and carbides nucleated on Al2O3. When carbides are of the same size, the number of carbides in test steel at a tempering temperature of 773–803 K is greater than that at a tempering temperature of 823–853 K, especially when the size of carbides is less than 5 μm. Compared with the test steel tempered at 823–853 K, the distance between adjacent actual particles reduced by 80.6 μm and the maximum amount of reduction was 9.4% for single wear loss at the tempering temperature of 773–803 K. It can be concluded from thermodynamics results that Al2O3 inclusions began to precipitate in liquid, and the precipitation of carbides was at the solid–liquid region. Al2O3 can be used as the nucleation interface of carbide, thus promoting the formation of carbides. During the cooling of molten steel, a lower temperature can increase the difference of actual solubility product bigger than equilibrium solubility product, thus promoting the carbide formation.

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Liu, Yang, Lei Wang, Yu Chen Wang, Hong Yan Liu, Xue Jiao Chen, and Yan Yu. "Effects of Electropulsing Treatment on the Precipitation Behaviour of Grain Boundary Carbides in GH3044 Alloy." Materials Science Forum 654-656 (June 2010): 464–67. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.464.

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The effects of electropulsing treatment on the precipitation behaviour of grain boundary carbides in GH3044 alloy were investigated. The results showed that the initial temperature of precipitation of M23C6 type carbides on grain boundary could be decreased by electropulsing treatment under the condition of high current density of 10.0kA/mm2 with a frequency of 5Hz and pulse width of 15s. The volume percentage of M23C6 type carbide was greatly increased to 274.60% comparing with that of the aging treatment at the same temperature. However, the precipitation of M23C6 type carbide was inhibited by electropulsing treatment under the condition of high frequency of 45Hz with the current density of 2kA/mm2 and pulse width of 15s. The volume percentage of M23C6 type carbide was decreased to 18.81% comparing with that of the aging treatment at the same temperature. It has been found that the diffusion of solute atom in the alloy can be promoted by the electric effect with the electropulsing. As a result, the thermodynamic condition and kinetics of the precipitation of M23C6 type carbide were changed, and both the initial and peak temperatures of precipitation were decreased.

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Jaworski, J., R. Kluz, and T. Trzepieciński. "Influence of Heat Treatment on Content of the Carbide Phases in the Microstructure of High-Speed Steel." Archives of Foundry Engineering 17, no. 3 (September 1, 2017): 59–62. http://dx.doi.org/10.1515/afe-2017-0091.

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Abstract This article presents the results of investigations of the effect of heat treatment temperature on the content of the carbide phase of HS3-1-2 and HS6-5-2 low-alloy high-speed steel. Analysis of the phase composition of carbides is carried out using the diffraction method. It is determined that with increasing austenitising temperature, the intensification of dissolution of M6C carbide increases. As a result, an increase in the grain size of the austenite and the amount of retained austenite causes a significant reduction in the hardness of hardened steel HS3-1-2 to be observed. The results of diffraction investigations showed that M7C3 carbides containing mainly Cr and Fe carbides and M6C carbides containing mainly Mo and W carbides are dissolved during austenitisation. During austenitisation of HS3-1-2 steel, the silicon is transferred from the matrix to carbides, thus replacing carbide-forming elements. An increase in a degree of tempering leads to intensification of carbide separation and this process reduce the grindability of tested steels.

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Li, Yongcheng, Siyu Chen, Fuhai Zhu, Chenglin Huang, Zhenqiang Zhang, Weidong Xuan, Jiang Wang, and Zhongming Ren. "Effect of High Magnetic Field in Combination with High-Temperature Tempering on Microstructures and Mechanical Properties of GCr15 Bearing Steel." Metals 12, no. 8 (July 31, 2022): 1293. http://dx.doi.org/10.3390/met12081293.

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The microstructures and mechanical properties of GCr15 bearing steel after high-temperature tempering with and without a 5 T high magnetic field (HMF) were investigated. It was found that the application of the HMF at the stage of high-temperature tempering slowed down the growth of the tempered sorbite (TS) structures, increased the density of the carbides, and reduced the carbide size and the volume fraction. XRD diffraction patterns showed that the HMF resulted in a higher dislocation density. Hardness testing indicated that the HMF led to an increase in the Vickers hardness in the tempered sample. It is inferred that the change in carbide size stems from the reduction in nucleation barrier in the HMF and the increase in dislocation density originates from the interaction between dislocations and carbides. Additionally, the decrease in diffusivity in the HMF also contributes to the reduction in the size of TS structures and the refinement of carbides. This work demonstrates that high-temperature tempering with an HMF can slow down the growth of TS microstructures in GCr15 bearing steel, control the carbide size, and improve Vickers hardness, which provides a new heat treatment method to regulate the microstructure and properties of GCr15 bearing steel.

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Chaus, Alexander S., Matej Beznák, and Miroslav Sahul. "Diffusion Induced Changes in Eutectic Carbides in Wrought M2 High-Speed Steel at Austenitising." Defect and Diffusion Forum 365 (July 2015): 5–10. http://dx.doi.org/10.4028/www.scientific.net/ddf.365.5.

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The influence of heat treatments on the microstructure of AISI M2 type high-speed steel obtained using conventional metallurgy has been studied. The primary focus was on the effects of austenitisation temperatures on the behaviour of the initial eutectic carbides during austenitisation. In order to investigate kinetics of both the microstructure and phase transformations in eutectic carbides upon heat treatments with respect to diffusion processes, different techniques of electron scanning microscopy and energy dispersive X-ray spectrometry have been used. The effect of the austenitisation temperature on the primary austenite grain size, martensite microstructure and volume fraction, size distribution, and morphology of the primary carbides of eutectic origin as well as their behaviour during heat treatment in the wrought M2 high-speed steel was thoroughly investigated.

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Chaus, Alexander S., Matej Beznák, M. Bohačík, Ján Porubský, and P. Úradník. "Effect of Austenitising Temperature on Structural Changes in Modified High-Speed Steel of AISI M2 Type." Defect and Diffusion Forum 326-328 (April 2012): 348–53. http://dx.doi.org/10.4028/www.scientific.net/ddf.326-328.348.

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The transformation of the solidification microstructure and the phase changes in AISI M2 grade high-speed steel modified with powder addition of TiB2have been studied focusing on the effect of austenitising temperatures. In order to investigate kinetics of both the microstructure and phase transformations in eutectic carbides, primarily M2C carbide decomposition, upon heat treatments with respect to diffusion processes, different techniques of electron scanning microscopy, X-ray diffraction analysis and energy dispersive X-ray spectrometry have been used.

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Xu, Xue Xia, Jie Ouyang, Yan Ting Feng, and Xiao Guang Niu. "Effect of Heat Treatment on Microstructure and Properties of P91 Steel." Advanced Materials Research 287-290 (July 2011): 1074–78. http://dx.doi.org/10.4028/www.scientific.net/amr.287-290.1074.

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The effect of improper heat treatment progress on the structure and properties of P91 steel was studied. Results showed that under aircooling conditions, although the normalization temperature is beyond conventional range, the hardness meets the requirements of ASME standard, and the microstructure appear a gradual transition from equiaxed ferrite with carbide precipitates to tempered martensite. In addition ,when normalization temperature was as high as 1150°C and 1250°C, there is an characteristic morphology of coarse martensite laths and some of them are orthogonal to each other. When normalization cooling rate is slowly at 1°C/min, the hardness dropped under the lower limit at reduced normalization temperatures and the microstructure consist of polygonized ferrite and carbide precipitates. SEM and TEM observation indicated that with the increasing normalization temperature the ferrite morphology transforms from coarse polygonized to finer equiaxed, and carbide precipitates not only along boundaries but also within the grain, at the same tine rod shape carbides formed at 1000°C normalization.

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Chen, Zhengyang, Qiang Guo, Hanguang Fu, and Xiaohui Zhi. "Effect of heat treatment on microstructure and properties of modified hypereutectic high chromium cast iron." Materials Testing 64, no. 1 (January 1, 2022): 33–54. http://dx.doi.org/10.1515/mt-2021-2010.

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Abstract The effect of heat treatment on the microstructure, hardness and wear resistance of modified hypereutectic high chromium cast iron (HCCI) was investigated. The results show that the quenching treatment partially dissolves the edges of the primary carbides, and the sharp corners become rounded and blunt. As the quenching temperature increases, the carbide re-dissolves into the matrix, and the hardness and wear resistance first increase and then decrease. The hardness and wear resistance are the best when quenched at 1000 °C. After tempering, the martensite is transformed into tempered martensite, and the precipitation of secondary carbides increases. As the tempering temperature increases, the secondary carbides gradually become coarser. When the tempering temperature is 500 °C, the hypereutectic HCCI shows the highest hardness and the best wear resistance. When tempered at 400 °C, hypereutectic HCCI shows the best erosion and wear resistance.

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Chotěborský, R., and P. Hrabě. "Effect of destabilization treatment on microstructure, hardness and abrasive wear of high chromium hardfacing." Research in Agricultural Engineering 59, No. 4 (December 5, 2013): 128–35. http://dx.doi.org/10.17221/6/2013-rae.

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Hardfacing metals are widely used in arc welding and plasma transfer arc technologies and industries. However, application of hardfacing in agriculture is limited due to low toughness after weld depositing. This study was focused on destabilization of high chromium hardfacing metal. The hardfacing was destabilized at 900 and 1,000°C in the different treatment time intervals. Destabilization treatment showed precipitation of secondary carbides leading to partial transformation of austenite to martensite phase in the matrix. The results show that increasing destabilization temperature increased volume of carbide phase in austenitic matrix which affects abrasive wear resistance.  

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Wu, Yan, Zhi Wei Zhang, Qian Wang, Na Xiao, and Xiang Zhao. "Effect of Magnetic Field Strength on Carbide Precipitation Behavior in W₆Mo₅Cr₄V₃High Speed Steel during Medium Temperature Tempering." Key Engineering Materials 709 (September 2016): 15–18. http://dx.doi.org/10.4028/www.scientific.net/kem.709.15.

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Effect of magnetic field strength on carbide precipitation behavior in W6Mo5Cr4V3 highspeed steel during medium temperature tempering was investigated. The applied magnetic field promoted the precipitation and refinement of M6C and MC carbides at boundaries and in the grain interior, but maximum spheroidization occurred for those M6C carbides precipitated at boundaries, the stronger the magnetic field strength, the stronger the spheroidization effect. The high magnetic field hinders the precipitation of M2C type carbides, and the M2C type carbides basically disappear when applying the magnetic field.

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Hamzah, Esah, Maureen Mudang, Ang Khwang Jenq, and Muhammad Adil Khattak. "High Temperature Creep Behavior of Austenitic Fe-Ni-Cr Alloy." Advanced Materials Research 686 (April 2013): 170–79. http://dx.doi.org/10.4028/www.scientific.net/amr.686.170.

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Creep damage investigation was carried out in Fe-Ni-Cr alloy at 800°C, 900°C, and 983°C using rectangular section form of specimen. In all the tests conducted on this material, some creep curves showed primary stage, secondary stage and tertiary stage. The creep fracture shows ductile transgranular fracture where separation occurred at the dendrites carbide interface suggesting that the detrimental effect of creep was compounded by precipitation of carbides at matrix. The presence of cavities may be due to the difference in thermal expansion characteristics of the austenite and carbide during high temperature test. Coarsening of carbides lead to cavities formation within the dendrite and carbide interface and form cavities linkage due to formation of crack and finally cause creep fracture. Increase in creep temperature it will lead to increase in creep rate. The fracture modes of creep samples were investigated to predict the failure mode.

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Li, Yanmei, Yonghao Cui, Jimou Zhang, Minghui Song, and Chen Xu. "Effects of Simulated PWHT on the Microstructure and Mechanical Properties of 2.25Cr1Mo0.25V Steel for a Hydrogenation Reactor." Metals 12, no. 11 (November 19, 2022): 1978. http://dx.doi.org/10.3390/met12111978.

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The effect of post-welding heat treatment (PWHT) on the microstructure and mechanical properties of large-thickness 2.25Cr1Mo0.25V steel was investigated through simulated post-welding heat treatment (SPWHT). The results showed that an increase in the SPWHT time decreased the toughness, hardness, and strength of the steel. After Min.SPWHT, the high-temperature tensile strength decreased more significantly, and the damage of Min.SPWHT to the high-temperature tensile strength reached approximately 80% of the Max.SPWHT. The microstructure of the tested steel before and after SPWHT consisted of granular bainite and lath bainite. After SPWHT, intergranular carbides were precipitated as coarsened carbides, carbide clusters, and chains of carbides; alloy element segregation occurred, and the segregation of Mo was the most serious, followed by Cr, and V. The precipitation behavior of the carbides and the increase in the effective grain size caused by the widening of the bainite–ferrite lath worked together and resulted in the decline of the impact toughness; the reduction in the solid solution and precipitation strengthening effects were the main factors in the strength reduction of the tested steel. In the high-temperature tensile tests, defects first appeared around the coarse carbides and carbide clusters. Controlling the size of the intergranular large-size carbides and the degree of cluster precipitation in the NT state structure may be a means of obtaining higher strength of the base metal subjected to PWHT.

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Moffat, James P., Tamsin E. Whitfield, Katerina A. Christofidou, Ed J. Pickering, Nicholas G. Jones, and Howard J. Stone. "The Effect of Heat Treatment on the Oxidation Resistance of Cobalt-Based Superalloys." Metals 10, no. 2 (February 12, 2020): 248. http://dx.doi.org/10.3390/met10020248.

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Degradation of the mechanical integrity of cobalt-based superalloys can occur as the carbide network is progressively oxidised during high temperature service. In this study, a heat-treatment aimed at redistributing the carbides was tested on two similar commercial Co-based superalloys, one with high C content (Co-101) and one with low C content (Stellite-21), to determine its influence on oxidation resistance. It was found that the carbide phases in the lower C-containing alloy could be solutioned more readily than the higher C-containing alloy, enabling the continuity of the carbide network to be reduced. This resulted in a reduced attack of the carbides down the interdendritic channels during oxidation testing, but increased thickness of the oxide overscale.

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Minote, Toru, Yoshimasa Funakawa, Naoko Saito, Mitsugi Fukahori, Hiroshi Hamasaki, and Fusahito Yoshida. "Mechanical Behavior of 980MPa NANOHITEN^TM at Elevated Temperatures and its Effect on Springback in Warm Forming." Key Engineering Materials 611-612 (May 2014): 11–18. http://dx.doi.org/10.4028/www.scientific.net/kem.611-612.11.

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High tensile strength steel sheets have large springback after being formend at room temperature. Warm forming can be a solution to reduce springback of high tensile strength steel parts. NANOHITENTM is a high strength ferritic steel precipitation-strengthened by nanometer-sized carbides developed by JFE Steel Corporation. Tensile strength of the steel at room temperature does not change before and after deformation at elevated temperatures up to 873K since the carbides in the steel are stable at high temperatures less than 973K. Therefore, the steel is suitable for warm forming. Springback of 980MPa NANOHITENTM parts warm formed at 873K is the same level of that of cold formed conventional 590MPa steel parts. In this study, two kinds of material testing at room temperature and at elevated temperatures between 573K and 937K were performed to understand the mechanical behavior of 980MPa NANOHITENTM: uniaxial tensile tests and bending tests. The steels flow stress depends on not only material temperature but also strain rate in uniaxial tensile tests. After a bending test, the specimen shows springback measured by the change of an angle between the two sides. Stress relaxation happens while a test specimen is held at the bottom dead point after bending. And the stress relaxation could be used to reduce springback of warm formed parts.

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Zhou, Rui, Xiao Gang Diao, Jun Chen, Xiao Nan Du, Guo Ding Yuan, and Gui Fang Sun. "Effect of Spark Plasma Sintering on the Microstructure Evolution and Properties of M3:2 High-Speed Steel." Materials Science Forum 788 (April 2014): 329–33. http://dx.doi.org/10.4028/www.scientific.net/msf.788.329.

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Effects of sintering temperatures on the microstructure and mechanical performance of SPS M3:2 high speed steel prepared by spark plasma sintering was studied. High speed steel sintering curve of continuous heating from ambient temperature to 1200°C was estimated to analyze the sintering processes and sintering temperature range. The sintering temperature within this range was divided into groups to investigate hardness, relative density and microstructure of M3:2 high-speed steel. Strip and quadrate carbides were observed inside the equiaxed grains. SPS sintering temperature at 900°C can lead to nearly full densification with grain size smaller than 20μm. The hardness and bending strength are higher than that of the conventionally powder metallurgy fabricated ones sintered at 1270°C. However, fracture toughness of the high speed steel is lower than that of the conventional powder metallurgy steels. This can be attributed to the shape and distribution of M6C carbides which reduce the impact toughness of high speed steels.

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Zhang, Lin, Dehai Gong, Yunchao Li, Xiaojun Wang, Xixi Ren, and Engang Wang. "Effect of Quenching Conditions on the Microstructure and Mechanical Properties of 51CrV4 Spring Steel." Metals 8, no. 12 (December 12, 2018): 1056. http://dx.doi.org/10.3390/met8121056.

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51CrV4 steel is extensively used in large-size damping springs for trains and vehicles. Quenching conditions play an important role in performance enhancement. The present work investigated the effects of various oil-bath temperatures and out-of-oil temperatures on the microstructure and the mechanical properties of this steel. The morphological examination focused on both the quenched martensite and the tempered troostite. Tensile and hardness tests were carried out to evaluate the mechanical properties. The results showed that a coarsening of the martensite occurred at a high oil-bath temperature. In addition, the size and fraction of bainite islands also increased with the increase of oil-bath temperature. In contrast, the carbide size and the intercarbide spacing both increased with the increase of oil-bath temperature. Thus, the tensile strength and the hardness both decreased with increasing oil-bath temperature in accordance with the Hall-Petch relationship. Correspondingly, the ductility increased as the oil-bath temperature increased. At a relatively high out-of-oil temperature, the martensite underwent an auto-tempering process, which led to the precipitation of many tiny carbide particles in the as-quenched martensite laths. This auto-tempering effect enhanced the width of large-sized carbides and reduced their length in the final microstructure. The intercarbide spacings increased with increasing out-of-oil temperature. As the oil-bath temperature increased, the tensile strength and hardness decreased, and the ductility increased. The fracture morphology was examined to explain the results of mechanical properties.

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Zhong, Zhao Xu, Xing Fu Yu, Ai Hua Huang, Yu Fei Wang, Yan Lin Man, and Shu Sen Cui. "Effect of Element V on the Microstructure and Mechanical Properties of DZ417G Superalloy." Materials Science Forum 788 (April 2014): 446–51. http://dx.doi.org/10.4028/www.scientific.net/msf.788.446.

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The effect of V content on the mechanical properties and microstructure of DZ417G alloy was studied in the present investigation. DZ417G alloy with different element V contents was smelted , then tested the mechanical properties and observed microstructure. The results show that with the increase of element V content, the morphology of rod type M23C6 carbides turned into block-type MC carbides, the size of carbides became bigger, and the amount of carbides decrased, but the dispersion degree of carbide in the matrix was increased. The alloy tensile strength and plastic properties were increased at high temperature with the increment of V content. There were finer dimple structures on the tensile rupture fracture surface of the alloy with high element V than the alloy with low element V under the high temperature conditions. The results of creep rupture life tests show that with increasing V content the creep rupture life increased at the test condition of 760 °C, 725MPa. The creep rupture life is 90h of the alloy with 0.62% V element content, and the creep rupture life increased to more than 245h when the element V content increased to 0.96%.

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26

Chotěborský, R. "Effect of heat treatment on the microstructure, hardness and abrasive wear resistance of high chromium hardfacing." Research in Agricultural Engineering 59, No. 1 (March 6, 2013): 23–28. http://dx.doi.org/10.17221/62/2011-rae.

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The effect of destabilization heat treatment on the microstructure, hardness, fracture toughness and abrasive wear resistance of high chromium hardfacing was investigated. The results from the study shows that the hardness, fracture toughness and abrasive wear resistance are influenced by temperature of destabilization heat treatment and air and furnace cooling conditions, respectively. Destabilization treatment of materials by furnace cooling caused higher secondary carbides in the dendritic austenite whilst by air cooling it showed smaller particles of secondary carbide. Also, it was found that destabilization temperature at 1,000°C improves hardness compared with hardfacing after weld depositing. The study, however, indicated that Palmqvist fracture toughness method is a useful technique for measuring the fracture toughness of high chromium hardfacing compared to Vicker’s hardness method.    

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27

Zhang, Ke, Maoyuan Zhu, Bitong Lan, Ping Liu, Wei Li, and Yonghua Rong. "The Mechanism of High-Strength Quenching-Partitioning-Tempering Martensitic Steel at Elevated Temperatures." Crystals 9, no. 2 (February 13, 2019): 94. http://dx.doi.org/10.3390/cryst9020094.

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High-strength medium-carbon martensitic steel was heat treated through a quenching-partitioning-tempering (Q-P-T) treatment. Both the mechanism for improved ductility and the high temperature stability of austenite were investigated. The Q-P-T martensitic steel showed good products of strength and elongation (PSE) at various deformation temperatures ranging within 25–350 °C. The optimum PSE value (>57,738 MPa%) was achieved at 200 °C. The microstructure of the Q-P-T steel is constituted of laths martensite with dislocations, retained austenite located within lath martensite and small niobium carbides (NbC), and/or transitional ε-carbides that precipitated in the lath martensite. The good ductility can be mainly attributed to the laminar-like austenite that remained within the lath-martensite. The austenite can effectively enhance ductility through the effect of dislocation absorption by the retained austenite and through transformation-induced plasticity. The relationship between the microstructures and mechanical properties was investigated at high deformation temperatures.

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Zhou, Xue Feng, Xiao Yan Yin, Feng Fang, and Jian Qing Jiang. "Effect of Calcium Modification on the Microstructure and Properties of High Speed Steel." Advanced Materials Research 217-218 (March 2011): 457–62. http://dx.doi.org/10.4028/www.scientific.net/amr.217-218.457.

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The present work has investigated the influence of calcium on the microstructure and properties of AISI M2 high speed steels. The results show that the as-cast structure consists of the iron matrix and networks of M2C eutectic carbides, which are greatly refined in the ingot modified by calcium. Meanwhile, the morphology of M2C evolves from the plate-like shape into the fibrous one. Compared with the plate-like M2C, the fibrous M2C is less stable at high temperatures, which promotes the spheroidization and refinement of carbides. Therefore, M2 steels modified by calcium obtain higher hardness and red-hardness after heat treatment than those without the addition of calcium.

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29

Yao, Xin, Jie Huang, Yanxin Qiao, Mingyue Sun, Bing Wang, and Bin Xu. "Precipitation Behavior of Carbides and Its Effect on the Microstructure and Mechanical Properties of 15CrNi3MoV Steel." Metals 12, no. 10 (October 19, 2022): 1758. http://dx.doi.org/10.3390/met12101758.

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In this study, quenching and tempering were employed to achieve the optimal match of strength and toughness of the high-strength low-alloy (HSLA) 15CrNi3MoV steel. The effect of the tempering temperature on the microstructure evolution and the carbides precipitation of the steel was also investigated using scanning electron microscopy (SEM), a X-ray diffractometer (XRD) and transmission electron microscopy (TEM). The results showed that after tempering at different temperatures, the microstructure of 15CrNi3MoV steel was tempered martensite. During the tempering process, the M3C carbides precipitated on the ferrite matrix, the needle-like carbides accumulated and grew into a short rodlike shape or a granular shape with the increase of the tempering temperature. Subsequently, the strength and hardness of the steel showed a downward trend, and the elongation and the low temperature impact toughness showed an upward trend. The tensile strength and yield strength of the steel tempered at 650 °C decreased dramatically compared with the steel tempered at 550 °C, while the elongation increased rapidly. Considering the influence of the microstructure and the carbides and the demand for mechanical properties, the optimal tempering temperature is about 600 °C.

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30

Lun, Huilin, Yi Zeng, Xiang Xiong, Ziming Ye, Zhongwei Zhang, Xingchao Li, Haikun Chen, and Yufeng Liu. "Oxidation behavior of non-stoichiometric (Zr,Hf,Ti)Cx carbide solid solution powders in air." Journal of Advanced Ceramics 10, no. 4 (July 13, 2021): 741–57. http://dx.doi.org/10.1007/s40145-021-0469-y.

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AbstractMulti-component solid solutions with non-stoichiometric compositions are characteristics of ultra-high temperature carbides as promising materials for hypersonic vehicles. However, for group IV transition-metal carbides, the oxidation behavior of multi-component non-stoichiometric (Zr,Hf,Ti)Cx carbide solid solution has not been clarified yet. The present work fabricated four kinds of (Zr,Hf,Ti)Cx carbide solid solution powders by free-pressureless spark plasma sintering to investigate the oxidation behavior of (Zr,Hf,Ti)Cx in air. The effects of metallic atom composition on oxidation resistance were examined. The results indicate that the oxidation kinetics of (Zr,Hf,Ti)Cx are composition dependent. A high Hf content in (Zr,Hf,Ti)Cx was beneficial to form an amorphous Zr-Hf-Ti-C-O oxycarbide layer as an oxygen barrier to enhance the initial oxidation resistance. Meanwhile, an equiatomic ratio of metallic atoms reduced the growth rate of (Zr,Hf,Ti)O2 oxide, increasing its phase stability at high temperatures, which improved the oxidation activation energy of (Zr, Hf, Ti)Cx.

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31

Qiao, Zhi Xia, Dan Tian Zhang, Yong Chang Liu, and Ze Sheng Yan. "Effect of Austenization Temperature on the Martensitic Transformation in a Low-Alloy Ultra-High-Strength Steel." Applied Mechanics and Materials 66-68 (July 2011): 1797–801. http://dx.doi.org/10.4028/www.scientific.net/amm.66-68.1797.

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The effect of austenization treatment temperature on the martensitic transformation in the 30CrNi3MoV ultra-high-strength steel was investigated by means of dilatometric measurements and microstructural observations. The results showed that the coarsening temperature of austenite grains in the 30CrNi3MoV steel is raised to about 1000°C due to the inhibition to the migration of austenite grain boundaries, not only by the fine and disperse vanadium carbides, but also by the solute atoms adsorbed near the boundaries. The martensite obtained in 30CrNi3MoV samples with different austenization temperatures varied in the structural constituent, as well as in the size. The martensite microstructures obtained in the samples austenized at relatively low temperatures were composed of both lath martensite and acicular martensite and they are small in size. Yet the microstructures in the 30CrNi3MoV samples with relatively high austenization temperatures were occupied mostly by coarse lath martensite. For the 30CrNi3MoV steel, the austenization heating temperature should be kept below 1000°C in order to achieve the optimum mechanical property.

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32

Ha, Tae Kwon, Kyu Dong Lee, Jin Hwa Song, and Hyo Tae Jeong. "Effect of Aging Treatment Conditions on the Microstructure and Strength of Fe-36Ni Based Invar Alloy." Key Engineering Materials 345-346 (August 2007): 109–12. http://dx.doi.org/10.4028/www.scientific.net/kem.345-346.109.

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Strengthening method for the Fe-36Ni based Invar alloy for power transmission wire was investigated in this study. High strength of 1300 MPa could be obtained in this alloy through solution hardening, precipitation hardening and strain hardening by cold working. Phase equilibrium of the Invar alloy was calculated using FactSage®, revealing that thermodynamically stable phases are Mo2C, MoC, M23C6-type FeCrMo carbide, and M6C-type FeMo carbides. Aging treatments were carried out at temperatures ranging from 400 to 900oC for time intervals from 3 min to 30 hrs. Peak aging condition was obtained as 400oC and 1 hr. With temperature increased, peak hardness was decreased abruptly. Microstructure observation was conducted by optical microscopy, scanning electron microscopy, and transmission electron microscopy. By using the result from aging treatment, high strength above 1300MPa was obtained in the cold rolled Invar alloy plate.

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33

Sun, Fan, D. Mantovani, and Frédéric Prima. "Carbides and their Role in Advanced Mechanical Properties of L605 Alloy: Implications for Medical Devices." Materials Science Forum 783-786 (May 2014): 1354–59. http://dx.doi.org/10.4028/www.scientific.net/msf.783-786.1354.

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L605 (ASTM F90), a cobalt-chromium-tungsten alloy with excellent mechanical properties and high radiopacity, has been widely accepted as a suitable alloy for stent applications. The presence of carbides in this alloy, primary carbides and secondary carbides, leads to difficulties in controlling mechanical performances and therefore in optimizing stent size and performances. This work is thus to investigate the carbides and their role in advanced mechanical properties of L605 alloy for stent fabrication. Herein, the nature, nucleation, distribution and dissolution of the carbides were investigated in a series of recrystallized L605 tubes from hard-drawn (HD) state. The mechanical properties corresponding to each carbide state were examined by tensile tests and microhardness measurements. The results indicate important relationships among carbide precipitation, grain size and mechanical behaviors, as a function of annealing temperature and duration. The intergranular secondary carbides, induced at the onset of the recrystallization of L605 matrix, were preferentially precipitated at grain boundaries. The nucleation of such particulate phase leads to a pinning effect on grain coarsening, resulting in a strengthening effect of the material. However, the further growth of the secondary carbides brings about considerable reduction of ductility, which is inacceptable for stent application. Therefore, an optimization protocol on carbides controlling was developed to maintain the strengthening effect without losing ductility and small grain size.

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34

Dudko, Valeriy, Andrey Belyakov, and Rustam Kaibyshev. "Effect of Tempering on Mechanical Properties and Microstructure of a 9% Cr Heat Resistant Steel." Materials Science Forum 706-709 (January 2012): 841–46. http://dx.doi.org/10.4028/www.scientific.net/msf.706-709.841.

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Effect of tempering temperature ranged from 400 to 720°C on mechanical properties and microstructure of a P92-type creep resistant steel was investigated. The hardness value of 400 HB, which was obtained after solution treatment, increased to 430 HB with increasing the tempering temperature to 525°С. Further increase in the tempering temperature resulted in gradual decrease in hardness, which approached a level of about 220 HB after tempering at 720°С. The equiaxed particles of MX-type carbonitrides with a size of about 30 nm were precipitated randomly after tempering under all conditions. At temperatures below 525°C, the tempered martensite lath structure (TMLS) was characterized by a random distribution of fine M3C-type carbides and MX-type carbonitrides. The precipitation of M23C6 was observed after tempering at T ≥ 525°C. At 525°C, the M23C6 carbides appeared as thin films on high-angle boundaries (HAB), while M23C6 particles having almost equiaxed shape and located on various boundaries including low-angle lath boundaries precipitate at higher temperatures.

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35

Ďurica, Juraj, Jana Ptačinová, and Peter Jurči. "Fracture Micromechanism of Cryogenically Processed Vanadis 6 Tool Steel." Defect and Diffusion Forum 395 (August 2019): 45–54. http://dx.doi.org/10.4028/www.scientific.net/ddf.395.45.

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The effect of cryogenic processing and tempering on selected mechanical properties and fracture micromechanism of Vanadis 6 high alloy cold work tool steel was analysed. The samples were processed in cold nitrogen gas at -140 °C for 48 h, and tempered at temperatures of 170 – 530 °C. It was found that the hardness of sub-zero treated Vanadis 6 steel decreases with increasing tempering temperature. The highest hardness of the specimen 960 HV10 was achieved by tempering at 170 °C and the lowest hardness 790 HV10 resulted from tempering at the highest tempering temperature, i.e. 530 °C. However, the hardness of conventional heat treated samples was less than 800 HV10 in full range of tempering temperatures. The fracture toughness of sub-zero treated samples does not differ from what was obtained by conventional heat treatment schedule except the case of the high tempering temperature of 530 °C where an increase in fracture toughness by approx.. 3 MPa.m1/2 has been recorded. The carbides differ clearly in their role in the fracture propagation. While the secondary carbides undergo easily cleavage the eutectic carbides assist more probably decohesive fracture propagation.

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36

Chen, Hua, Rong Feng Zhou, Ye Hua Jiang, and Rong Zhou. "Effect of Electric Current Pulse on Carbide in Hypereutectic High Chromium Cast Iron." Advanced Materials Research 457-458 (January 2012): 174–80. http://dx.doi.org/10.4028/www.scientific.net/amr.457-458.174.

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It has significant engineering practicability that refining the carbides as hard phase in hypereutectic high chromium cast iron. The high chromium cast iron samples during the course of solidification were treated with electric current pulse (ECP) from the temperature of 1350 °C and 1360 °C. The effects of ECP treatment of starting temperature, processing time on the shape, size, and distribution of primary carbides was investigated. The mechanism of primary carbides refined by ECP process was also analyzed preliminarily.

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37

Zhang, Hui, Jian Xin Deng, Gui Yu Li, Xing Ai, and Jun Zhao. "Effect of Ambient Temperature on Wear of Cemented Carbide Tool Material." Advanced Materials Research 148-149 (October 2010): 276–79. http://dx.doi.org/10.4028/www.scientific.net/amr.148-149.276.

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Cemented carbide has relatively good mechanical properties, so it is widely used as cutting tools. In this paper, a sliding wear test at high ambient temperature between cemented carbide tool material and ceramic was carried out using a ball-on-disc wear-test machine. The characteristics as to wear rate and friction coefficient were investigated. The special wear rate increased with an increase in operating temperature. The cemented carbide material with addition of TiC phase gave better wear resistance than cemented tungsten carbides at elevated temperature. SEM technology was adopted to observe the worn surfaces of specimens and wear mechanism were simultaneously discussed.

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38

Jiang, Zhi Qiang, Xi Lan Feng, and Xian Zhang Feng. "A Study on the Effects of Heat Treatment to the High-Carbon HSS Roll." Advanced Materials Research 129-131 (August 2010): 500–505. http://dx.doi.org/10.4028/www.scientific.net/amr.129-131.500.

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High-carbon high-speed steels (HSS) are extremely abrasion resistant materials due to their high hardness MC type carbide and high hardness martensitic matrix. Different microstructures and mechanical behaviours were obtained after the quenching and tempering temperatures of HSS roll were changed. With air cooling and sodium silicate quenching, when the austenitizing temperature reaches 1273K, the metal matrix all transforms into the martensite, Afterwards, the eutectic carbides dissolve ceaselessly into the metal matrix and its continuous network distribution changes into broken network. The peak hardness temperature of high-carbon HSS is around 1323K, and the second hardening temperature is around 793K. No significant change in tensile strength and elongation percentage was observed unless the tempering temperature is beyond 753K. The tensile strength is increased obviously and the elongation percentage is decreased slightly beyond 753K. However, the tensile strength is decreased and the elongation percentage is increased when the temp exceeds 813K. The high-carbon HSS roll presents excellent abrasion resistance at 793K-813K.

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39

Yaoita, Shinji, Takehiko Watanabe, and Tomohiro Sasaki. "Brazing of Cemented Carbides at Lower Temperatures." Advanced Materials Research 409 (November 2011): 865–70. http://dx.doi.org/10.4028/www.scientific.net/amr.409.865.

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Cemented carbides have been widely used for cutting tools because of their high hardness and abrasion resistance. Since the cemented carbides are so expensive, it is desirable to reuse a tool shank made of cemented carbides. For the reason, so far, a new blade of a tool has been brazed to used shanks. However, when cemented carbides are heated for brazing, heating inevitably causes the deterioration in the mechanical properties. This study was carried out to braze the cemented carbides at lower temperatures for reducing the deterioration of the shank. First of all, authors developed a new Ag-based brazing filler metal with a low melting point of about 605°C, and investigated the effects of the new Ag filler metal on the properties of a brazed joint. Moreover, Co element or Ni element was added into the Ag filler metal to make the bending strength of a brazed joint improved. The addition of Co element increased the bending strength of a joint and the strength was equivalent to that of a joint brazed at 750°C using a conventional Ag filler metal, but the addition of Ni element decreased the bending strength of a brazed joint.

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40

Kresser, S., R. Schneider, H. Zunko, and C. Sommitsch. "A Model to Predict the Microstructural Constituents after Quenching and Partitioning of Martensitic Stainless Steels." HTM Journal of Heat Treatment and Materials 76, no. 2 (April 1, 2021): 120–31. http://dx.doi.org/10.1515/htm-2020-0008.

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Abstract The typical heat treatment of martensitic stainless steels comprises hardening and subsequent tempering. Depending on the application and size of the component, tempering is carried out either at low temperatures (< 300 °C) or at high temperatures (> 500 °C). In this paper, tempering at lower temperatures is examined. First, the austenitizing step is considered in greater detail and an optimized formula for the calculation of the MS temperature of such steel grades is created in order to enable to be modelled. For the calculations, the austenite composition is determined at different austenitizing temperatures using thermodynamic simulation. Furthermore, the transformation of austenite into martensite during quenching is described with the help of the Koistinen-Marburger equation. The second part deals with effects in the material at low holding temperatures. Here, the influence of different hardening temperatures and interception temperatures of the quenching procedure is investigated. There is no complete partitioning at temperatures of 300 °C. Certain tempering processes can also take place, such as the formation of transition carbides, so-called M3C carbides. A typical tempering with formation of stable Cr-rich carbides does not occur at this low temperature. Finally, the calculated results of the model correlate well with microstructural investigations (XRD, LOM). ◼

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Donlon, W. T., W. E. Dowling, C. E. Cambell, and J. E. Allison. "The effect of thermal exposure on precipitation of Ti3Al(C,N) in Ti-48Al-IV-0.2C." Proceedings, annual meeting, Electron Microscopy Society of America 50, no. 1 (August 1992): 22–23. http://dx.doi.org/10.1017/s0424820100120515.

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Titanium aluminides are attractive candidates for high temperature structural applications because of their high strength to weight ratio at elevated temperatures. The microstructure of these alloys consists of γ-TiAl (distorted L10 structure) , plus α2-Ti3Al (ordered DO19 structure). Varying the heat treatment temperature and cooling rate of these alloys alters the volume fraction and distribution of the γ and α2 phases. This has significant effects on the room temperature ductility. In addition, precipitation of carbides has been observed during high temperature exposure. The effect of these precipitates on the mechanical properties has yet to be determined.Figure 1 shows the general microstructure that was used for this investigation. TEM foils were prepared by electropolishing using 5% perchloric, 35% 1-butanol, 60% methanol at -40°C. No precipitates were found following heat treatment in the γ+α phase field. Samples approximately 20 mm square were thermally exposed to temperatures between 625° and 1000°C for times between 1 and 2000 hours.

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42

Cui, Yi, Yun Fei Zhang, Yan Guang Han, and Da Lv. "Influence of High Temperature Annealing on Microstructure Evolution of Ni-24Fe-14Cr-8Mo Superalloy." Key Engineering Materials 904 (November 22, 2021): 117–23. http://dx.doi.org/10.4028/www.scientific.net/kem.904.117.

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The effect of high temperature annealing on microstructure evolution of Ni-24Fe-14Cr-8Mo alloy was investigated through Optical Microscopy (OM), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD) and Rockwell Hardness Testing Machine. Three kinds of grain growth patterns were found at different annealing temperatures due to carbides precipitation and dissolution. After a combination of high temperature annealing and aging treatment, the hardness versus time curves performed a parabolic pattern. The highest hardness was achieved under 1070°C/60 minutes treatment, and the desirable annealing time should be 60 minutes to 90 minutes.

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43

Fábián, Enikö Réka, and Áron Kótai. "Cold Rolling Effect on Microstructure and Mechanical Properties of Low Carbon Al-Killed Steels." Materials Science Forum 812 (February 2015): 315–20. http://dx.doi.org/10.4028/www.scientific.net/msf.812.315.

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It have been studied the cold rolling effects on the microstructure of samples prepared from Al-killed low carbon steel sheets with high coiling temperatures. The microstructure of the hot rolled steels sheet is formed from ferrite and large carbides when the coiling temperature is high. The cold rolling affects the steel mechanical and electrochemical properties due to microstructural changes. We have studied the microstructure by optical microscope and scanning electron microscope. Low angles grain boundaries and the texture of samples were studied by EBSD method.

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44

Tarraste, Marek, Jakob Kübarsepp, Arvo Mere, Kristjan Juhani, Märt Kolnes, and Mart Viljus. "Ultrafine Cemented Carbides with Cobalt and Iron Binders Prepared via Reactive In Situ Sintering." Solid State Phenomena 320 (June 30, 2021): 176–80. http://dx.doi.org/10.4028/www.scientific.net/ssp.320.176.

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Reactive sintering of cemented carbides involves mechanical and thermal activation of precursor elemental powders, followed by in-situ synthesis of tungsten carbide. This approach promotes formation of ultrafine microstructure favored in many cemented carbide applications. Our study focuses on the effect of mechanical activation (high-energy milling) on the properties of powder and following thermal activation (sintering) on the microstructure characteristics and phase composition. Reactive sintering proved effective – an ultrafine grained microstructure of cemented carbides with Co and Fe binders was achieved. Formation of tungsten carbide grains was complete at low temperature during reactive spark plasma sintering, resulting in textured microstructure with anisotropic grain formation and growth.

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45

Ibrahim, Khaled M., and Mervat M. Ibrahim. "Heat Treatment in High Chromium White Cast Iron Ti Alloy." Journal of Metallurgy 2014 (April 29, 2014): 1–9. http://dx.doi.org/10.1155/2014/856408.

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The influence of heat treatment on microstructure and mechanical properties of high chromium white cast iron alloyed with titanium was investigated. The austenitizing temperatures of 980°C and 1150°C for 1 hour each followed by tempering at 260°C for 2 hours have been performed and the effect of these treatments on wear resistance/impact toughness combination is reported. The microstructure of irons austenitized at 1150°C showed a fine precipitate of secondary carbides (M6C23) in a matrix of eutectic austenite and eutectic carbides (M7C3). At 980°C, the structure consisted of spheroidal martensite matrix, small amounts of fine secondary carbides, and eutectic carbides. Titanium carbides (TiC) particles with cuboidal morphology were uniformly distributed in both matrices. Irons austenitized at 980°C showed relatively higher tensile strength compared to those austenitized at 1150°C, while the latter showed higher impact toughness. For both cases, optimum tensile strength was reported for the irons alloyed with 1.31% Ti, whereas maximum impact toughness was obtained for the irons without Ti-addition. Higher wear resistance was obtained for the samples austenitized at 980°C compared to the irons treated at 1150°C. For both treatments, optimum wear resistance was obtained with 1.3% Ti.

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46

Zhong, Jinyan, Zun Chen, Shanglin Yang, Songmei Li, Jianhua Liu, and Mei Yu. "Effect of Solution and Aging Temperatures on Microstructure and Mechanical Properties of 10Cr13Co13Mo5Ni3W1VE(S280) Steel." Micromachines 12, no. 5 (May 17, 2021): 566. http://dx.doi.org/10.3390/mi12050566.

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The article investigated the effects of solution and ging temperatures on microstructure and mechanical properties of ultra-high strength stainless steel 10Cr13Co13Mo5Ni3W1VE(S280). Higher solution temperatures can improve impact toughness because of the quantity reduction of submicron-sized particles which act as microporous nucleation sites. S280 has the best mechanical properties at 1080 °C solution temperature. After quenching, the steel is completely martensite with almost no retained austenite. Aging at 560 °C results in peak strength due to the precipitation of fine carbides coherent zones. The loss of precipitates/matrix coherency and precipitates coarsening cause a decrease in strength at higher aging temperatures. Good strength and toughness obtained at 540 °C aging temperature are attributed to fine and dispersed strengthening phases such as Cr2C and Fe2Mo, and the recovery of austenite in high-density dislocation martensite matrix. The details of electron microscopy research, strengthening and toughening mechanisms are discussed.

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47

Han, Bin, Yong Wang, Yi Shan Li, and Rui Liu. "Effect of Laser Scanning and Aging Treatment on Microstructure and Property of Austenitic Heat-Resistant Steel." Key Engineering Materials 373-374 (March 2008): 416–20. http://dx.doi.org/10.4028/www.scientific.net/kem.373-374.416.

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In order to improve surface properties, high chromium austenitic base heat-resistant cast steel was scanned with a 5kW continuous wave CO2 laser, the specimen was aged at the temperature of 600°C~900°C. The microstructure and phase composition of the specimen were analysed with optical microscopy, electronic microscope and X-ray diffractionse. The hardness was measured. The results show that as-cast structure of high chromium cast steel is coarse and non-homogeneous, and mainly consist of austenite, ledeburite and carbides. After laser surface melting, the section is divided into the melted zone consisted of fine austenite and carbides, the heat affected zone composed of austenite and eutectic carbides, and the base meta1. The melted zone is very fine structures with dendritic crystals, only at the bottom a cellular structure is observed. A continuous carbide network is located in the austenitic grain boundaries at the heat affected zone. Carbides particles distribute dispersed out, the hardness of melted zone increases 35% than the base metal after aging. The area and the hardness of various zones are related to the laser processing parameters. The hardening depth of melted zone and heat affected zone may be up to 200μm~300μm.

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48

Taylor, M., J. W. Fellowes, P. O. Hill, M. J. Rawson, T. L. Burnett, and E. J. Pickering. "The Effect of Compositional Heterogeneity on the Martensite Start Temperature of a High Strength Steel During Rapid Austenitisation and Cooling." IOP Conference Series: Materials Science and Engineering 1249, no. 1 (July 1, 2022): 012061. http://dx.doi.org/10.1088/1757-899x/1249/1/012061.

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Abstract Many low alloy steels are compositionally heterogeneous due to the preferential segregation of alloying elements to the dendritic or interdendritic regions when the steel is first solidified (microsegregation). This segregation is often ignored when using CCT diagrams to predict the phase transformation behaviour of steels, but may be of importance in some industrially-relevant cases. This work focuses on the martensite start temperature (Ms ) of Super CMV, a high strength aerospace steel, after rapid austenitisation treatment to various peak temperatures from 900 °C to 1300 °C. It was found that the average Ms temperature increased with increasing peak temperature (and prior austenite grain size) at peak temperatures of 1100°C and above, which is to be expected conventionally. However, at peak temperatures of below 1100°C, the Ms temperature increased with decreasing prior-austenite grain size. It is proposed that this was due to the presence of non-dissolved carbides in these conditions, particularly in enriched bands of material, which deplete the matrix and hence raise Ms .

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Mulholland, Michael D., and David N. Seidman. "Voltage-Pulsed and Laser-Pulsed Atom Probe Tomography of a Multiphase High-Strength Low-Carbon Steel." Microscopy and Microanalysis 17, no. 6 (October 27, 2011): 950–62. http://dx.doi.org/10.1017/s1431927611011895.

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AbstractThe differences in artifacts associated with voltage-pulsed and laser-pulsed (wavelength = 532 or 355 nm) atom-probe tomographic (APT) analyses of nanoscale precipitation in a high-strength low-carbon steel are assessed using a local-electrode atom-probe tomograph. It is found that the interfacial width of nanoscale Cu precipitates increases with increasing specimen apex temperatures induced by higher laser pulse energies (0.6–2 nJ pulse−1 at a wavelength of 532 nm). This effect is probably due to surface diffusion of Cu atoms. Increasing the specimen apex temperature by using pulse energies up to 2 nJ pulse−1 at a wavelength of 532 nm is also found to increase the severity of the local magnification effect for nanoscale M2C metal carbide precipitates, which is indicated by a decrease of the local atomic density inside the carbides from 68 ± 6 nm−3 (voltage pulsing) to as small as 3.5 ± 0.8 nm−3. Methods are proposed to solve these problems based on comparisons with the results obtained from voltage-pulsed APT experiments. Essentially, application of the Cu precipitate compositions and local atomic density of M2C metal carbide precipitates measured by voltage-pulsed APT to 532 or 355 nm wavelength laser-pulsed data permits correct quantification of precipitation.

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SUH, CHANG-MIN, GYE-WON CHOI, KYUNG-RYUL KIM, and MOON-SIK HAN. "THE EFFECT OF CARBIDES PRECIPITATION ON THE SLIDING WEAR CHARACTERISTICS ACCORDING TO HEAT TREATMENT CONDITIONS." International Journal of Modern Physics B 20, no. 25n27 (October 30, 2006): 4426–31. http://dx.doi.org/10.1142/s021797920604146x.

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This study investigated the effect of carbide precipitation hardening of heat-treated SK5M steel on the sliding wear resistance. The cold rolled carbon steel strip samples (J, G, and S-type) were oil quenched after tempering for optimal durations. The wear resistance was evaluated using a pin-on-disk wear test with an alumina counterface against different samples at various loads and distances with a constant running speed. The size and distribution of the precipitated carbides were observed using an image analyzer at various heat treatments. The heat-treated samples presented more dense carbide distribution in an area fraction and the decreased size of carbides. It is confirmed that the wear rate is minimum at an optimized austenitizing temperature of around 800°C. The specific wear rate indicates that the S-type sample has high wear resistance compared to that of J-Type. This is understood by stable wear behavior of S-type sample containing evenly distributed carbide precipitation.

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Journal articles on the topic 'Carbides Effect of high temperatures on'

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