最新刊期
卷 45 ， 期 4 ， 2024
- 摘要：The high-end equipment industries in the fields of aerospace， energy， petrochemical， shipbuilding， rail transportation， new energy vehicles， energy conservation and environmental protection， and electronic information have developed strongly， putting forward higher requirements for the quality and performance of special steel and special alloy materials， and the demand has surged. Therefore， in recent ten years， China's special metallurgy industry has been rapidly development. This paper first analyzes and summarizes the new requirements of ultra-high strength steel， supper alloy， corrosion resistant alloy， heat resistant steel， special stainless steel， high performance bearing steel， tool and die steel and precision alloy for the above-mentioned high-end equipment manufacturing. Secondly， the development status and trend of traditional special metallurgical processes and several new special metallurgical processes are analyzed. It is emphasized that the combination with basic oxygen furnace/electric arc furnace steelmaking process can provide high clean consumable electrode for electroslag remelting and vacuum arc remelting， and can also provide pure raw material for vacuum induction furnace. The short process of the electroslag remelting with continuous casting billet as the consumable electrode can significantly improve the production efficiency and reduce the production cost. At the same time， the duplex process of high nitrogen stainless steel smelting and the process flow of powder metallurgy and spray forming of tool and die steel are also briefly introduced. Third， China's special metallurgical industry development status， as well as the progress of new technology and new equipment have been summarized. Finally， suggestions and prospects for the technical development of special metallurgy in China in the next ten years are put forward.关键词：Special Metallurgy;Special Steel;Special Alloy;Process Flow;Metallurgical Equipment9|8|0更新时间：2025-05-09
- 摘要：With the continuous improvement of material requirements for high-performance aviation engines， the degree of alloying and the mass fraction of the γ' phase in new nickel-based superalloys for high-temperature applications continue to increase. This leads to progressively more challenging melting processes for these alloys. High-alloyed wrought nickel-based deformation superalloys are generally produced through a triple combination process of Vacuum Induction Melting （VIM） + Protective Atmosphere Electro-Slag Remelting （PESR） + Vacuum Arc Remelting （VAR）. Due to the influence of alloying degree， alloys are prone to solute segregation and elemental partitioning between liquid and solid phases during the melting process， making electrodes and ingots susceptible to cracking under the combined effects of thermal stress and phase transformation stress. This not only causes arc fluctuations during the subsequent remelting process but also adversely affects the quality of the ingots. Electrode crack formation is a complex metallurgical defect that occurs in the solidification process of superalloys and has been a common technical challenge that has long plagued the expansion of ingot sizes for high-alloy， difficult-to-deform superalloys in China. Therefore， this paper reviews the recent research progress of the author’s team and research groups at home and abroad in the crack formation mechanism， influencing factors of crack and crack control of wrought nickel-based superalloys， and looks forward to the future development direction of wrought superalloy precipitation strengthened nickel-based superalloys.关键词：Triple Melting;Highly alloyed;Wrought Superalloy;Formation Mechanism of Crack;Crack Control4|2|0更新时间：2025-05-09
- 摘要：Pressurized electroslag remelting （PESR） is currently the most effective production route for industrial preparation of high nitrogen steel and high nitrogen alloys， and is currently a research focus and the most advanced technology in the field of electroslag metallurgy. This article introduces the development of the integrated line equipments， process technology， and main product characteristics of PESR. A review is conducted on the core components of the nitrogen alloy feeding system and water-gas dynamic balance system in the current PESR furnace equipment. In response to the current technological difficulties in PESR process， this paper elaborates on the development of new technologies such as the mechanism and method of nitrogen addition and gas-phase nitrogen addition technology for nitriding alloys， development of a new high-efficiency heating refining remelting slag system， and precise element control. In recent years， with the application of series newly built domestically produced pilot scale PESR furnaces and the successful development of series of high nitrogen steel products， China has made a significant breakthroughs in the integrated line equipment independent research and technological development， and gradually stepped forward to the international advanced level.At the same time， deepening the independent research and development of industrial grade PESR equipment and process technology research and development， ensuring the preparation of key materials urgently needed for high-quality special steels and special alloys in China's aviation， aerospace， and military industries fields and so on， is an important direction for the development of modern electroslag metallurgy technology in China.关键词：Pressurized Electroslag Remelting;High Nitrogen Steel;Nitrogen Alloying;Slag System;Process Development5|4|0更新时间：2025-05-09
- 摘要：As one of the indispensable core components of advanced aero-engine， nickel-based single crystal turbine blades （hereinafter referred to as single-crystal blades） have extremely demanding requirements in terms of dimensional accuracy of the hollow structure， uniformity of alloying element distribution， and metallurgical quality of the surface and inner cavity. It is found that the control of temperature gradient during directional solidification directly affects the performance and quality of single crystal blades， and whether the continuous acquisition of stable heat flow becomes the key of directional solidification .With the continuous progress of computer technology， numerical simulation has become one of the important methods of single crystal blade directional solidification research. Firstly， introduce the single crystal blade technology is introduced and the heat transfer method in the directional solidification process is then analyzed.Secondly， the optimization methods of boundary conditions of interfacial heat transfer coefficient for numerical simulation are summarized， focusing on the application of Beck's inverse method and finite difference method in the solution of interfacial heat transfer coefficient. The results proves that the two methods can be used to solve the interfacial heat transfer coefficient between castings/shells， where the accuracy of the simulation of the temperature field can be effectively improved.Finally， the research progress of numerical simulation of the temperature field during directional solidification is also traced， and the influence of process parameters on the temperature field is summarized. Based on the analysis of the research progress of numerical simulation of temperature field during directional solidification of nickel-based single crystal turbine blades， the optimization direction of the directional solidification process and the subsequent development trend of the related technology are proposed to promote the research and development process of single crystal turbine blades.关键词：Nickel-based Single Crystal Turbine Blade;Directional Solidification;Numerical Simulation;Temperature Field;Interfacial Heat Transfer Coefficient4|0|0更新时间：2025-05-09
Overview
- 摘要：A fully coupled flow heat mass model was established based on the phase field method to simulate the growth of columnar crystals in ingots during vacuum arc remelting （VAR） in a forced flow field. The influence mechanism of melt flow on the growth of columnar crystals was analyzed by comparing the growth characteristics of columnar crystals with and without flow field conditions.The simulation results indicated that when the velocity of flow field in the solidification front is 45 μm/s and the direction is perpendicular to the direction of dendrite growth， the secondary dendrites exhibit ‘counter-flow’ growth， and the dendrite trunks tilt downstream due to erosion. A small eddy current is formed between adjacent dendrites， and the solutes and the heat in the upstream of the dendrite trunks are carried into the downstream side with the melt. The boundary layer thickness of the solute and the temperature on the upstream side decreases， from 51 μm in the absence of a flow field to 31.5 μm. The large temperature gradient promotes the development of secondary dendrites. The concentration of solutes and heat in the downstream boundary layer is high， and the boundary layer thickness increases to 78 μm. The decrease in gradient significantly inhibits the development of secondary dendrites. The downstream solute concentration is higher than that in the absence of a flow field， and the slow growth of dendrites increases the risk of micro-segregation.关键词：Vacuum Arc Remelting;Phase Field;Columnar Crystal Growth;Forced Flow Field;Solute Field;Temperature Field2|0|0更新时间：2025-05-09
- 摘要：The effect of different electron beam refining parameters on the type， quantity and size distribution of inclusions during melt solidification was studied. The content of O and N in FGH4096 alloy and the type， quantity and size distribution of inclusions after different power refining were statistically analyzed， and the mechanism of influence of power on inclusions growth during electron beam refining was revealed in combination with the growth kinetics of inclusions. The number density of carbon and nitrogen compounds and complex phase inclusions in FGH4096 alloys prepared by electron beam refining was the largest， and the proportion of both was 95.53%. In the carbon nitrogen compounds and complex phase inclusions， TiN-TiC， TiN-（Ti，M）C and Al2O3-TiN-（Ti，M）C occupied a large proportion. The inclusions growth kinetics calculations showed that when the power increased from 9 kW to 12 kW， the increased power improved the removal effect of the inclusions forming elements， limited the elemental content required for the growth of inclusions， reduced the formation temperature of inclusions and thus reduced its growth temperature range， and led to a reduced growth time and size of inclusions due to the small change in the cooling rate additionally.However， when the power 12 kW increased to 15 kW， the O and N content decreased less while the melt cooling rate decreased larger， resulting in an increased growth time of the inclusion.It reduced the effect of the removal of impurity element content， with an increase in the size of inclusions.关键词：Electron Beam Refining;FGH4096;Inclusion;Kinetics3|0|0更新时间：2025-05-09
- 摘要：To study the vacuum arc remelting process and improve the homogenization and cleanliness level of large-sized superalloy ingot， numerical simulation and industrial experiment were carried out to investigate the evolution of molten pool， solidification characteristics and inclusion distribution in a
- 摘要：A
- 摘要：In this paper， a transverse static magnetic field was applied in the electroslag remelting （ESR） process of M2 high-speed steel. The effects of superimposed transverse static magnetic field on the solidification structure， inclusions and mechanical properties of M2 high speed steel were investigated by methods of optical microscope， scanning electron microscope and metal inclusion analyzer.The results show that the solidification microstructure of M2 ESR ingot is improved after the application of transverse static magnetic field， and the grain growth angle decreases from 52.03° to 21.99°. The depth of molten pool is reduced from 44.2 mm to 18.8 mm. The eutectic carbides are refined from coarse network to fine eutectic carbides. At the same time， the efficiency of inclusions removal is improved， and the number of inclusions in the 4 mm2 detection area is reduced to 1 064 compared to 2 119 without the magnetic field. In addition， hardness uniformity is improved in both transverse and longitudinal sections of the electroslag ingot. The analysis shows that the change of the morphology and grain growth angle of the metal pool under the transverse static magnetic field is due to the periodic electromagnetic oscillation effect on the droplet transformation characteristics， which causes the metal droplet to be broken in the low process and makes the temperature distribution in the molten pool more uniform， leading to the shallow flattening of the metal pool. In the electroslag remelting process， the transverse magnetic field reduces the local solidification time by the way of shallow flat melting pool， thus inhibiting the dynamic conditions of the growth of eutectic carbides and obtaining finer eutectic carbides. In terms of inclusions， the transverse static magnetic field can promote the removal of inclusions in the three phases of liquid film layer， droplet and pool.关键词：Magnetic-Controlled Electroslag Remelting;Transverse Static Magnetic;M2 High-speed Steel;Solidification Structure;Eutectic Carbide;Inclusion;Uniformity of Hardness2|1|0更新时间：2025-05-09
- 摘要：Based on the laboratory small-scale low-frequency electroslag remelting device， taking 70%CaF2+30%Al2O3 electroslag remelting 304L austenitic stainless steel as the research object， we analyze in detail the influence of different remelting current on the number， size dimension and type of inclusions in the electroslag ingot under low-frequency conditions. The results show that compared with the power frequency electroslag remelting （50 Hz， 1 800 A）， the oxygen （O） content in electroslag ingot increased by 172.2% and 75.5% respectively under the condition of low frequency （2 Hz） and different current （1 800 and 1 400 A）. Nitrogen （N） content decreased by 4% and 3.4%， respectively.At low frequency， the type of inclusions in the electroslag ingot did not change when remelted with different current， but the number of inclusions and the proportion of each type of inclusions changed. The number of inclusions decreases with the decrease of current intensity at low frequency， However， compared with the power frequency condition， the amount of debris still increased by 173% （1 800 A） and 63.7% （1 400 A）， and the increase part was basically small inclusions below 10 μm， and the amount of large-size inclusions （>10 μm） increased less.关键词：Electroslag Remelting;Current;Low Frequency;Inclusion;Cleanliness2|0|0更新时间：2025-05-09
- 摘要：During the process of electric arc remelting， the content of gas components （such as H， O， N， etc.） in the steel is significantly influenced by the gas permeability of the slag system used. In order to explore a slag system with low hydrogen permeability suitable for nuclear-grade 316H stainless steel in electric arc remelting， the hydrogen permeability of five slag systems used in electric arc remelting was determined. The results showed that the newly developed 63%CaF2-30%Al2O3-7%MgO slag system had the lowest hydrogen permeability.meanwhile the hydrogen permeability of slag system， 65%CaF2-30%Al2O3-5%MgO， was similar to that of the 63%CaF2-30%Al2O3-7%MgO slag system， and hydrogen permeability of both slag systems exhibited a significant reduction compared to the original slag system used in the steel plant's electric arc production，declined from 6.58×10-6 mol/（cm·min） to 1.89×10-6 mol/（cm·min） and 2.18×10-6 mol/（cm·min） respectively.The higher the optical basicity of the slag was， the higher the hydrogen permeability was. CaO in the slag had a high affinity for water and can easily increase the hydrogen content in the steel ingot during electric arc remelting， while the addition of MgO in the slag system can significantly reduce hydrogen permeability. Under the research conditions， the influence of the slag system's constituents on its hydrogen permeability was more significant than the optical basicity.关键词：Electric Slag Remelting;Austenitic Stainless Steel;316H;Nuclear Power;Hydrogen Content3|0|0更新时间：2025-05-09
- 摘要：Non-metallic inclusion is a important factor affecting the fatigue property of high-temperature bearing steel. The effect of electroslag remelting （ESR） using 37 slag on inclusions of M50 high-temperature bearing steel was investigated in order to improve the level of inclusion control. Inclusions were characterized by field emission scanning electron microscope equipped with energy dispersive spectrometer. The ingredients of slags before and after ESR was analyzed by X-ray fluorescence method. In the consumable electrode， inclusions were finer Al2O3-SiO2 with high SiO2 content （about 29.3% in average value）. No inclusions clusters were observed.After ESR， inclusions changed to Al2O3， the clusters inclusions with large size were observed. The content of SiO2 in the slag increased from 1.73% to 3.42%， and the Al2O3 content decreased； The content of Al in the steel increased significantly from <0.000 5% to 0.020 7%， and the content of Si in the steel decreased from 0.356% to 0.296%. The metallurgical reaction during ESR was explained based on slag-steel reaction theory. The dissolved Si in the steel reacted with Al2O3 of the molten slag at the interface between molten steel and slag， and the products were dissolved Al and SiO2. Subsequently， dissolved Al diffused into the molten steel and reacted with SiO2 of the inclusions， and the products were dissolved Si and Al2O3. In the end， inclusions in the steel were transformed into Al2O3.The methods to control inclusions of M50 bearing steel during ESR using 37 slag were proposed.关键词：Electroslag Remelting;High-temperature Bearing Steel;M50;Inclusions;Slag-steel Reaction;37 Slag4|0|0更新时间：2025-05-09
- 摘要：The new process of EAF→VOD→LF+VD→ pouring 6 t electrode rod → vacuum consumable remelting （VAR） with lower smelting cost was adopted to produce 15-5PH stainless steel instead of the traditional VIM+VAR process， the causes of point defects were analyzed by scanning electron microscopy and ASPEX detection methods. The results show that calcium aluminate and aluminum spinite exist in the self-consuming electrode， the instability of vacuum consumable remelting process will draw the ingot crown and non-metallic float into the melting pool and remain in the consumable ingot， resulting in point defects after forging.Through process optimization and improvement， the VOD reduction slag is adjusted from 9 kg/t aluminum to 8 kg/t ferrosilicon and 5 kg/t aluminum， the composition of refining slag is adjusted from （mass fraction）CaO 50%-55%， SiO2 10%-15%， Al2O3 20%-25% to CaO 45%-50%， SiO2 5%-10%， Al2O3 33%-38%， vacuum consumable remelting speed is increased from 4.2 kg/min to 6 kg/min， and the melting drop time is increased from 0.23 s to 0.27 s， the cleanliness of consumable electrode has been greatly improved， the melting speed has been controlled steadily， the non-metal floating matter on the liquid surface of the molten pool has been removed， low and high magnification inspection of the finished material have met the standard requirements， and the inspection pass rate has been increased to more than 98%.关键词：15-5PH Stainless Steel;Point Defects;Refining Slag System;VAR;Droplet Time6|2|0更新时间：2025-05-09
- 摘要：As the quality of electroslag steel continues to be improved， the ordinary electroslag furnace requires urgent upgrading to a fully airtight atmosphere protection system， aiming to address issues such as element burning loss， oxygen and hydrogen increase， and hydrogen porosity during the electroslag remelting （ESR） process. A novel atmosphere modification technology for electroslag furnaces has been used to conduct the comparative experiments between the traditional atmosphere protection electroslag furnace and the novel electroslag furnace on GCr15SiMn bearing steel and GH2132 superalloy， using electroslag furnaces with capacities of 5 t and 2 t， respectively.In the novel electroslag furnace， it has achieved an oxygen partial pressure as low as 1×10-6 in the mold during the melting process. The experimental results show that under traditional atmosphere protection in electroslag furnaces， the titanium yield in GH2132 is low， only 88%； The oxygen increase in GCr15SiMn bearing steel during the ESR process ，w［O］ can reach up to 5×10-6.In the novel atmosphere protection modification， the titanium yield in GH2132 reaches as high as 96%； The oxygen w［O］ increase in bearing steel during the ESR process is controlled within 3×10-6， and the oxygen w［O］ content in the electroslag ingot is stably controlled within 10×10-6. The quality of the electroslag ingots matches that of atmosphere-protected electroslag furnaces.In the remelting process， bearing steel w［O］ is controlled within 3×10-6， w［O］ in electric slag ingot is controlled within 10×10-6， and the effect of electric slag ingot is comparable to that of gas protection slag furnace. Above detection results of oxygen partial pressure in furnace and electric slag ingot show that after electric slag furnace atmosphere modification， it can effectively solve the problems like slag oxygen potential increase and the electric slag ingot caused by the oxide skin falling into the slag， which are the traditional atmosphere protection transformation technology， the recurrent heat wave emission and negative pressure suction caused by the unstable argon protection in the mold， resulting in the electrode surface oxidation， Especially for GH2132 high Ti low Al type superalloy， under the condition of adding deoxidant Al in ordinary electric slag furnace， it can only cause Al increase in electric slag ingot.关键词：Electroslag Remelting;Atmosphere Protection;Titanium Burning Loss;GCr15SiMn Bearing Steel;GH2132 superalloy2|0|0更新时间：2025-05-09
- 摘要：In order to obtain high-quality rare earth containing single crystal blades， the effect of La content on the wettability and interface reaction between CMSX-4 single crystal alloy and ceramic mould was studied by the droplet method.The experimental results show that when the 90×10-6 La is added， the wetting angle between the alloy and the mould decreases slightly， and only Al reacts with SiO2 in the mould and the reaction product is Al2O3. When the La content in the alloy reaches 143×10-6， and the wetting angle between the alloy and the mould decreases significantly， and both La and Al in the alloy react with SiO2 in the mould. Subsequently the La content continue to increase， and the lanthanum aluminate compounds with different La and Al atomic ratios are precipitated at the interface， and the wetting angle changes little. It can be seen that in the present experitment 143×10-6 is the critical content of interfacial reaction of La in CMSX-4 single crystal alloy， and the reaction between La and SiO2 can improve the wettability of the alloy/mould system.关键词：La Content;CMSX-4 Single Crystal Alloy;Wettability;Interfacial Reaction4|0|0更新时间：2025-05-09
- 摘要：The precise control of nitrogen content of high nitrogen stainless steel is the key control factor of production. Taking Mn18Cr18N high nitrogen steel as an example， this paper studies the relationship between steel composition， temperature， nitrogen pressure and nitrogen content control in pressure induction melting process by using metallurgical principle， factage thermodynamic software and thermal state experiment and detection analysis methods.The results show that the reliability of the "composition temperature pressure" relationship equation based on the theoretical data is high， and the theoretical and predicted values of nitrogen pressure in the three heats experiment are in good agreement with the actual control values. The thermal experiment finds that when the contents of Mn and Cr remain unchanged， increasing the nitrogen partial pressure can increase the N content in the ingot， but when the nitrogen reaches about 1%， the effect of increasing the nitrogen content by increasing the nitrogen partial pressure decreases.When the content of Mn or Cr is low， the nitrogen content can be increased by increasing the nitrogen partial pressure. Reducing the content of C and Si in steel is beneficial to the alloying and stable control of high nitrogen content in steel. It is advisable to control the melting temperature of the pressure furnace at 1 500-1 550 ℃ and the nitrogen pressure at 0.225-0.325 MPa when the nitrogen content in Mn18Cr19N steel is necessary to be controlled ≥ 0.8%.关键词：Mn18Cr18N;High Nitrogen Steel;Pressure Melting;Thermodynamics;Nitrogen Content3|0|0更新时间：2025-05-09
- 摘要：The effect of La treatment on the transformation of inclusions in H13 steel was investigated by subjecting H13 die steel to vacuum induction melting and subsequently treating the molten steel with La under an argon atmosphere protection.The results demonstrate that La has a beneficial effect on inclusions in H13 steel， the number of inclusions increases with the increase of La content， while the average size of inclusions initially decreases and then increases. The inclusions in H13 steel without the rare earth La additions are primarily Al₂O₃ and MnS. However， with a La content of 0.016% in H13 steel， the dominant inclusions shift to La2O2S. When the La content in H13 steel is 0.016%， the inclusions in the steel are mainly La2O2S；Furthermore， when the La content reaches 0.045% and 0.073%， the predominant inclusions in steel become LaP and La2O2S. Thermodynamic calculations show that the transformation process of La-treated inclusions is Al2O3→LaAlO3→La2O2S in molten steel at 1 600 ℃. During the solidification process， La2S3 is initially precipitated in the molten steel. As the temperature continues to decline， LaP begins to precipitate on the surface of La2S3 and La2O2S， ultimately forming the composite inclusions La2O2S-LaP and La2S3-LaP.关键词：H13 Hot Work Die Steel;La Treatment;Inclusions;Thermodynamic Calculation374|2|0更新时间：2025-05-09
Smelting and Solidification
- 摘要：The effects of powder particle size， powder treatment technology and powder treatment environment on oxygen content of FGH95 alloy were studied by chemical composition analysis， scanning electron microscope， transmission electron microscope （TEM） and mechanical property detection. The results showed that the powder treatment environment had great influence on the oxygen content and microstructure of FGH95 alloy， and the oxygen content of the alloy was increased by 115% compared with that of the degassed alloy prepared in the inert gas environment after the atomized powder treated in air with the same particle size， the oxygen content of FGH95 alloy prepared in low oxygen environment was only 0.003 9%， which significantly improved the PPB structure in the alloy.Similarly the oxygen content of FGH95 alloy prepared by 0-45 μm powder increased by 33% than that by 0-75 μm powder after the degassed treatment at room temperature and 450 ℃ in the inert gas environment. Powder treatment temperature has little effect on oxygen content of alloy which prepared by powder treated in low oxygen environment under the same conditions. The FGH95 alloy with different oxygen content had little effect on the strength at room temperature， but the ductility of the alloy was decreased with the increase of oxygen content.关键词：Nickel-based Superalloy;Powders;Oxygen Content;Hot Isostatic Pressure;Microstructure;Mechanical Properties3|0|0更新时间：2025-05-09
- 摘要：The dynamic recrystallization behavior of 1Cr16Co5Ni2MoWVNbN heat-resistant steel during thermal deformation was studied by thermal compression simulation experiments. The effects of strain rate and blank size on the die forging process of 1Cr16Co5Ni2MoWVNbN heat-resistant steel ball seat were studied by Deform 3D finite element numerical simulation. The results of thermal compression test showed that the critical deformation of 1Cr16Co5Ni2MoWVNbN heat-resistant steel was about 20% when full dynamic recrystallization happened and the phenomenon of mixed crystalline was not obvious. And increasing the strain rate was conducive to obtaining a more uniform structure under small deformation. The numerical simulation results showed that with the increase of the strain rate， the equivalent strain and equivalent stress in the minimum deformation area of the die forging increased. And With the increase of the diameter of the blank， the equivalent strain in the minimum deformation zone of the die forging decreased， and the equivalent stress decreased first and then increased. When the strain rate is 0.1 s-1， and the diameter of the blank is 60 mm - 65 mm， the engineering strain in the minimum deformation area can reach more than 20%， and it had good forging formability. According to the numerical simulation results， a blank size with diameter of 60 mm and height of 74 mm was designed to verifying the forming of the die forging with strain rate of 0.1 s-1. The forgings were well formed， uniform in structure and hardness， which verified the rationality and feasibility of the numerical simulation results.关键词：1Cr16Co5Ni2MoWVNbN Heat-resistant Steel;Numerical Simulation;Die forging forming;Deform 3D software;Dynamic recrystallisation2|0|0更新时间：2025-05-09
- 摘要：The effect of heat treatment process on the microstructure and properties of 140 ksi grade In718 alloy was studied. The solid solution temperature adopted three temperatures： 1 023 ℃， 1 030 ℃ and 1 050 ℃， and the aging temperature adopted three temperatures： 760 ℃， 780 ℃ and 800 ℃， the total of 9 sets of experimental data were cross tested. Then the alloy samples after different heat treatment processes were tested for room temperature tensile， -60 ℃ Charpy V-notch impact ， hardness， grain structure and other indicators， and analysis of the fracture structure and precipitates were analyzed. Research has shown that as the solid solution temperature increases， the strength of In718 alloy decreases， the plasticity and toughness increase， the grain size increases and δ phase decreases； At the same solid solution temperature， as the effective temperature increases at any time， the strength of In718 alloy decreases and the plasticity and toughness increase. The aging temperature has no effect on the grain size. γ″phase gradually coarsens from granular and spherical to needle like， and the number of γ″phases also shows a decreasing trend. Among them， the comprehensive performance of alloy is the best after solid solution treatment at 1 023 ℃ and aging treatment at 760 ℃， and the matching of indicators such as tensile strength， yield strength， plasticity， and impact toughness reaches the best level.关键词：Heat Treatment Process;In718 Alloy;Organization;Properties;Precipitate Phase7|0|0更新时间：2025-05-09
- 摘要：Based on the need of high wear resistance， a new kind of high-vanadium high-speed steel named W3Mo4Cr5V6 was designed. The transformation behavior of metastable M2C carbides in the high temperature heating process of the steel was analyzed by means of SEM and EMPA. The results show that the cophortic M2C carbide will undergo M2C+γ-Fe→M6C+MC+M7C3 transition at high temperature heating process.A large number of W， Mo-rich M6C and a small amount of V-rich MC and Cr-rich M7C3 are formed around the Mo and W-rich M2C phase. With the increase of temperature from 950 ℃ to 1 150 ℃， the high temperature transformation of M2C carbides gradually tends to be complete and the fibrous M2C is easier to decompose and transform than lamellar M2C， and the lamellar or fibrous morphology distributed in the austenite grain boundary with discontinuous network is transformed into the granular morphology distributed at the grain boundary， which can effectively reduce the harm of network carbides to the grain boundary. The research can provide an effective reference for the composition and morphology control of carbides distributed at the grain boundaries of high-speed steel and the optimal selection of parameters such as temperature and time of hot processing and heat treatment process.关键词：High-speed Steel;Electroslag Remelting;M2C Carbide;High Temperature Transition;Component Analysis2|0|0更新时间：2025-05-09
- 摘要：The effects of Quenching-Tempering-Austempering （QTA） duplex phase heat treatment process （Q 1 030 ℃， 30 min； T 520 ℃， 2 h； A 250 ℃， 3 h） at different prequenching temperatures on the microstructure， mechanical properties and the friction and wear properties of cold working die steel DC53 were investigated and the results were compared with those of the conventional Quenching-Tempering （QT） heat treatment process （Q 1 030 ℃， 30 min； T 520 ℃， 2 h）. The results show that the microstructure obtained by QT process is mainly tempered martensite and the microstructure mainly composing Lower Bainite/Martensite （LB/M） duplex phase can be resulted from the QTA process. The strength reduction due to the LB and the retained austenite （AR） can be partly offset by the grain refinement strengthening from the refinement of original austenite grain by duplex phases， and the impact toughness of DC53 can be greatly improved by this complex microstructure. Compared with the mechanical properties of the QT process， the hardness of the QTA at prequenching temperature 100 ℃ is only 1.4 HRC lower but the impact absorption energy is 2.44 times higher. Therefore， superior combination of strength and toughness can be obtained by the QTA process.关键词：Cold Working Die Steel;DC53;Heat Treatment;Microstructure;Mechanical Property416|0|0更新时间：2025-05-09
Forming and Phase Transition
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