最新刊期
卷 46 ， 期 3 ， 2025
- 摘要：The integrated fast reactors use metallic fuel， with fuel cladding operating at temperatures ranging from 350 ℃ to 630 ℃ and a service lifespan exceeding 50 000 hours. As the operational cycle extends， the fast neutron irradiation dose of the cladding will increase from the current 80 dpa of MOX fuel to 150 dpa-300 dpa. Therefore， the developing new cladding materials with high thermal resistance and excellent irradiation performance has become an important part of the integrated fast reactor development. This paper summarized the background of ferritic/martensitic steels （FM steels） development， analyzed the mechanical properties and irradiation performance of various FM steels， and investigated the influence of different alloying elements on these properties. Based on these analyses， alloy optimization strategies for FM steels suitable for integrated fast reactor fuel cladding were proposed. The optimization strategy was initially modified for HT9 steel， and the modified HT9G was tested for room temperature tensile test and 700 ℃/100 MPa creep rupture life. The results show that the modified alloy exhibits excellent tensile strength and creep rupture life， its room temperature yield strength reaches 880 MPa， which is approximately 310 MPa higher than that of T91 steel and 80 MPa-120 MPa higher than that of HT9 and T92 steels. Under conditions of 700 ℃ and 100 MPa， the creep rupture life is 372 hours-385 hours， significantly exceeding the 70 hours-82 hours of HT9 under the same conditions. It shows the effectiveness of toughening design， laying the foundation for further optimization of component structural materials and enhancement of long-term durability and strength improvement.关键词：Integrated Fast Reactor;Fuel cladding;Ferritic/martensitic steel;Irradiation performance;Creep property21|2|0更新时间：2025-05-09
Overview
- 摘要：The behaviors of interelectrode arc during vacuum arc remelting of high-temperature alloy and special stainless steel were investigated in this paper， and the influence factors such as electrode size， external quality， and gas element content on arc stability were analyzed. The results showed that large deviation of electrode diameter significantly affected the calculation of rod base speed， resulting in abnormal adjustment of arc gap， short circuits， and deviation of droplet frequency. The electrode taper should be controlled to be ≤0.5%. Cracks and shrinkage cavities defect on the electrode interfered with arc stability control， especially radial cracks leading to severe instability of droplets and remelting rates. Gas overflow was significant with high nitrogen in base material， which caused arc deviation， fluctuations in droplet and atmosphere pressure. Therefore， it is advisable to control w［N］≤0.003% during electrode preparation. There were obvious differences in equipment among different furnaces， and appropriate PID parameters should be explored.关键词：VAR;Arc Behavior;Stability;Consumable Electrode17|4|0更新时间：2025-05-09
- 摘要：GH4151 is a high-performance precipitation strengthened new nickel-based high temperature alloy， suitable for the manufacture of aviation engine turbine disc forgings. Based on the industrially validated MeltFlow software， the effects of different smelting process parameters on the electroslag remelting process of GH4151 alloy were studied. The results revealed with the process of the electroslag remelting， the morphology distribution of the molten pool exhibited a deep central region and shallow periphery at different smelting stages. Ultimately， the melt pool solidified at the center of the slag pool-liquid metal interface. ；As the melt speed was increased from 1.5 kg/min to 4.5 kg/min， the maximum depth of the melt pool increased from 360 mm to 474 mm， and the maximum width of the paste zone expanded from 60 mm to 99 mm. Furthermore， the local solidification time， the spacing of secondary dendrites， and the probability of black spot formation all exhibited a notable increase. As the electrode diameter increased （with the filling ratio rising from 0.27 to 0.94）， the depth of the melt pool and the width of the mushy zone showed no change. However， the volume of the melt pool decreased by 0.001 5 m³， and the thickness of the slag skin reduced by approximately 1 mm. The probability of black spot formation and the local solidification time both decreased as the electrode diameter increased. Therefore， the melting speed should have been reduced， and the electrode diameter （filling ratio） should have been increased， which would have been more favorable for the solidification quality of alloy.关键词：GH4151 Alloy;Electroslag Remelting;Melting speed;Filling Ratio13|5|0更新时间：2025-05-09
- 摘要：This study aims to optimize the homogenization process of 316H austenitic stainless steel slabs through simulation calculations using the Thermo-Calc software， with the goal of reducing the high-temperature ferrite content in the final product. The equilibrium and non-equilibrium solidification path simulations were conducted， in combination with metallographic analysis of actual cast slab samples， to determine the optimal homogenization heat treatment parameters， thus effectively reducing the ferrite content.Prior to optimization， the slab was homogenized at 1 250 ℃ for 1 000 minutes， resulting in a final product ferrite content of 3% to 4%. Through improvements to the homogenization process， the process was adjusted to two stages，： the first stage involved holding at 1 250 ℃ for 250 minutes， followed by the second stage at 1 180 ℃ for 250 minutes. The optimized process reduced the ferrite content in the finished product to below 1%， while significantly improving the material's microstructure. After the process optimization， the tensile strength and impact toughness of the finished product at room temperature met the material standard requirements. Moreover， the experimental results indicate that adjusting the homogenization temperature and holding time effectively promotes the transformation of ferrite to austenite and reduces the segregation within the solid solution.关键词：316H;Scheil Solidification8|1|0更新时间：2025-05-09
Smelting and Solidification
- 摘要：In this paper， the preparation of Ni-Cr-Al alloy by the smelting process of 200 kg vacuum induction + vacuum arc remelting（VIM+VAR） was analyzed by means of tensile test at room temperature， optical microscope and hardness test （/%：0.01C， 0.10-0.20Si， 0.20~0.40Mn， 0.01P， 0.01S， 15.50Cr， 4.50Al， 3.00Fe， 0.005-0.01Y， 0.005-0.01Zr）. The influence of different pass deformation amount on the mechanical properties of Ni-Cr-Al alloy was studied. The experimental results show that the tensile strength， yield strength and Vickers hardness of the alloy increase gradually with the increase of accumulated cold drawing deformation， and the area reduction and elongation decrease gradually. When the deformation amount increases to a certain extent， the mechanical properties of alloy basically do not change.When the cumulative deformation of Ni-Cr-Al alloy reaches 78.7%， its performance is the best. The tensile strength at room temperature， yield strength， section shrinkage， elongation and Vickers hardness of Ni-Cr-Al alloy are 1 449 MPa， 1 130 MPa， 45%， 10% and 476， respectively.关键词：Ni-Cr-Al Alloy;Cold-Drawing;Deformation Amount;Mechanical Property5|3|0更新时间：2025-05-09
- 摘要：Using conventional heat treatment combined with electrical pulse treatment （abbreviated EPT） ，the M2 high-speed steel was processed and the microstructure was observed using microscope， SEM and EBSD， the bending resistance of the specimen was tested. The results showed that the prior austenite grains （abbreviated PAGs） size of sample pretreated at 1 200 ℃ was about 24 μm， the austenite grain size was significantly refined after EPT， the grain size was refined to 4.8 μm while quenching at 1 140 ℃.The maximum bending strength of the refined M2 high-speed steel reached to 3 799 MPa， which was 39% higher than quenching at 1 180 ℃ of conventional heat treatment（abbreviated CHT）.Compared with the size change of austenite grain of M2 high-speed steel during the CHT ， it can be found that the grain refinement effect produced by EPT was not due to cyclic quenching， but it should be due to the high overheat generated by rapid heating and the influence of non-thermal effect on the nucleation rate.关键词：M2 High-speed Steel;Grain Refinement;Electropulsing Treatment;Bending Strength.5|3|0更新时间：2025-05-09
- 摘要：The microstructure of normalized & tempered 9Cr-2W-3Co martensitic heat-resistant steel and its tensile strength and fracture mechanism at different strain rates （5×100， 5×10-1， 5×10-2， 5×10-3， 5×10-4 s-1） at 625 ℃ was researched. The results showed that the tempered lath martensitic structure of 9Cr-2W-3Co martensitic heat-resistant steel was mainly structure obtained after normalizing and tempering， and there were a large number of chromium-containing carbide precipitation phase at the interface between the original austenite grain boundary and the lath bundle， and a certain density of dislocations in the matrix. The test steel was stretched at 625 ℃， with the increasing of strain rate， the yield strength of steel increased from 237 MPa to 430 MPa， the tensile strength was increased from 268 MPa to 480 MPa， and the reduction of area was between 28% and 15.5%. There were a large number of dimples of different sizes in the fracture， and there were high density dislocation in the test steel matrix at different strain rates. The dislocation interacts with the interface of inclusions or lath or precipitates， leading to the initiation and expansion of micropores， and eventually the fracture of the material.关键词：Martensitic Heat-resistant Steel;Strain Rate;Precipitated Phase;Inclusion;Dislocation9|1|0更新时间：2025-05-09
- 摘要：Taking the deep processing properties of 430 ferritic stainless steel as the background， the influence mechanism of rare earth Ce on the equiaxed crystal ratio of 430 ferritic stainless steel was studied. By studying the relationship between the number density， size of rare earth inclusions and equiaxed crystal ratio， the mechanism of the increase of the equiaxed crystal ratio by the rare earth Ce is obtained. The results show that with the increase of Ce content from 0% to 0.039%， the number density of Ce-containing inclusions increases from 0 per/mm2 to 194.37 per/mm2， the equiaxed crystal ratio increased from 28.3% to 84.4%， and the corresponding equiaxed grain size decreased from 1 910 μm to 310 μm. Based on thermodynamic calculations， with the increase of Ce content， SiO2 inclusions are gradually modified to Ce-O， and the heterogeneous nucleation of Ce inclusions on ferrite is the main reason for the increase in equiaxed grain rate of 430 ferritic stainless steel. The CAFE calculation model of PROCAST also indicates that as the number density of nucleating agent particles increases， the equiaxed grain rate gradually increases， and the theoretical calculation results are basically consistent with the actual observation results.关键词：Elemental Ce;430 Ferrite Stainless Steel;Equiaxed Crystal Ratio;Heterogeneous Nucleation183|2|0更新时间：2025-05-09
- 摘要：The steel rebar with low cost and excellent corrosion resistance were prepared by adding trace lanthanum （La） and cerium （Ce） rare earth elements. The effect of rare earth addition on the microstructure and corrosion resistance of corrosion resistant steel was studied by means of electrochemical workstation， X-ray diffraction （XRD） and scanning electron microscope （SEM）. The results show that rare earth elements refine the grain size and promote the transformation of MnS and Al2O3 ·SiO2 composite inclusions with long and irregular shape into spherical inclusions （Ce，La） 2O2S with smaller size and more regular shape. Following the addition of rare earth elements， the corrosion potential of the steel shifts positively， while the corrosion current is reduced. Furthermore， rare earth elements contribute to the reduction of unstable γ-FeOOH in the corrosion products， promoting the formation of more stable α-FeOOH， which enhances the stability， compactness， and adhesion of the rust layer. As the rare earth content increases， the corrosion resistance of the steel gradually improves， with the optimal performance observed in the steel containing 0.01% rare earth elements.关键词：Rare Earth Alloying;Corrosion Resistant Steel;Inclusion Modification;Corrosive Properties213|1|0更新时间：2025-05-09
Product Research and Development
- 摘要：The effect of curling temperature on the mechanical properties of Ti microalloyed high-strength steels was investigated using electron backscatter diffraction， transmission electron microscopy， scanning electron microscopy and mechanical experiments.The results show that with the increase of curling temperature， the grain size and the proportion of small-angle grain boundaries of steel increase， while the large-angle grain boundaries and dislocation density decrease. When the curling temperature increases from 595 ℃ to 625 ℃， the tensile strength of the steel decreases by 4%， the elongation increases by 32%， and the low temperature impact toughness decreases by 53%. The migration and elimination of large-angle grain boundaries and the increase of grain size ， the reinforcement of fine grain strengthening is weakened thus reducing the strength and low temperature toughness of steel. The increase of the proportion of small-angle grain boundaries in steel and the decrease of dislocation density effectively prevents the propagation of cracks and the occurrence of brittle fracture， thus improving the plasticity of steel.When the curling temperature is 610 °C， the tensile strength and low-temperature impact toughness of the steel do not decrease significantly， and the steel has a high elongation. With the ongoing increase in the coiling temperature， there is a substantial reduction in the strength and low-temperature impact resilience of the steel.关键词：Curling Temperature;Ti Microalloyed Steel;High Strength Steel GCL700;Tensile Properties;Impact Toughness;Microstructure4|2|0更新时间：2025-05-09
- 摘要：In order to obtain GH4169 alloy wire with stable microstructure and properties， the effects of different cold drawing deformation and annealing process on the microstructure and properties of GH4169 alloy wire were studied.Two cold deformation paths were used to prepare
- 摘要：Two-dimensional and three-dimensional phase field models were constructed using KKS model to investigate the three-dimensional microstructure growth mechanism of Fe-1.5% C alloy during solidification.Through high-temperature laser confocal technology， in-situ observation of the binary alloy structure is achieved， and the observed results are compared with simulation data to verify the accuracy of the phase-field simulation. The results indicate that the length of dendrite growth is significantly different at different cooling rates.Further analysis reveals that the three-dimensional phase-field simulation exhibits higher accuracy in predicting dendrite growth during alloy solidification compared to two-dimensional simulations. When the cooling rate is 2 000 ℃/min， the primary dendrite growth length in the three-dimensional simulation reaches 0.6 µm， which is close to the experimental value of 0.5 µm. However， when the cooling rate increases to 3 000 ℃/min， the three-dimensional simulation result is 1.4 µm， highly consistent with the experimental observation value of 1.45 µm. Additionally， the anisotropy strength plays a decisive role in dendrite growth， with a critical value of 0.045 determining the stability of dendrite growth in both two-dimensional and three-dimensional spaces. Once this critical value is exceeded， it will lead to the dendrite instability关键词：Fe-1.5% C alloy;Dendrite Growth;High-temperature Laser Confocal Microscopy;Binary Alloy4|2|0更新时间：2025-05-09
- 摘要：After induction heating， the SA-106B seamless steel pipe has cracks during hot bending process， the physical and chemical properties of the SA-106B seamless steel pipe and the hardness uniformity of the full cross-section were analyzed， and the cracking samples were tested by optical microscope. Combined with energy spectrum analysis， the hot bending cracking was confirmed to be caused by the contact between the surface of the steel pipe and the Cu parts during the production process. Caused by Cu adhesion to the surface of the steel pipe， the formation of a molten Cu-rich phase during induction heating， the rich Cu-rich phase erosion of the steel pipe surface of the grain boundary， and along the grain boundary to spread inward， resulting in "copper brittle" cracking under tensile stress After a comprehensive investigation， the improvement measures are proposed to replace the material of the outlet guide barrel of the straightener from “brass” to nylon sheet， which can effectively avoid "copper brittle" cracking. The analysis shows that copper fittings and similar low melting point metal fittings cannot be used in the production process of steel pipes that need to be hot bent， so as to avoid cracking caused by "copper brittleness" and cracking caused by pollution of low melting point metal materials. At the same time， during the transfer， loading， unloading and storage process， care should also be taken to avoid contact with copper fittings and similar low-melting metals.关键词：SA-106B;Steel Pipe;Hot Bending;Copper Brittle;Grain Boundary Cracking;Cu-rich Phase8|2|0更新时间：2025-05-09
- 摘要：The effects of tempering at 380 ℃- 620 ℃ on the microstructure and mechanical properties of the double-vacuum smelting secondary hardening steel were studied by optical microscope （OM）， scanning electron microscope （SEM）， JMat Pro software and tensile test. The test results showed that when tempering at 380 ℃-620 ℃， the matrix of the test steel changes from tempered lath martensite to tempered sorbite with the tempering temperature increasing， while the austenite increases. The tensile strength and yield strength reached their peak value at 440 ℃， which may be related to the increase of the strength of the test steel caused by the precipitation of Fe3C during tempering. The tensile strength and yield strength gradually decreased when tempering at 440 ℃- 620 ℃. Elongation and section shrinkage gradually increased. In addition， the fracture form of impact fracture changes from quasi-cleavage fracture to ductile fracture + quasi-cleavage fracture. The comprehensive test results showed that the test steel has the best mechanical properties when tempered at 496 ℃， and can achieve better strength and toughness matching.关键词：Gear steel;Microstructure;Mechanical Properties;Tempering Temperature3|1|0更新时间：2025-05-09
- 摘要：Different parameters such as deformation temperature and deformation rate were set for thermal compression tests， using the Thermecmastor-Z thermal simulation testing machine. The stress-strain curves and metallographic structures were analyzed to systematically study the high-temperature thermal deformation behavior and morphological evolution of the GH500 superalloy. The results showed that the stress-strain curves exhibited characteristics of work hardening， dynamic recovery， and dynamic recrystallization， with stress significantly increasing as the deformation temperature decreased and the deformation rate increased. At a deformation rate of 1 s-1， as the deformation temperature increased， the microstructure of the alloy evolved from deformed grains and small clusters of grains into fully recrystallized grains. When the deformation temperature was ≥1 130 ℃， the volume fraction and size of the dynamic recrystallized grains of the alloy significantly increased with the rise in deformation rate. At a deformation temperature of 1 180 ℃ and a deformation rate of 1 s-1， the alloy underwent complete dynamic recrystallization with no deformed grains， resulting in fine and uniform grains. Based on the stress-strain curves and microstructural evolution obtained from hot compression tests， suitable forging processes have been explored. The heating temperature was set between 1 130 ℃ and 1 150 ℃， and the reduction speed was 10 mm/s to 15 mm/s with the deformation rate betweem 0.04s-1 and 0.06 s-1 during the forging process. The produced alloy disc exhibit a basically uniform grain structure. After standard heat treatment， the room temperature tensile strength， hardness， and high-temperature durability of alloy disc meet the standard requirements.关键词：Deformation Temperature;Deformation Rate;Dynamic Recrystallization;Microstructure6|3|0更新时间：2025-05-09
- 摘要：According to the evolution law of microstructure and properties during the entire hot rolling process of ultra-high strength 92Si wire rod， methods such as mechanical property testing and microstructure characterization were used to analyze the continuous casting billet， samples before intermediate rolling， samples before finishing rolling， and finished wire rod during the hot rolling process. The results showed that with the gradual improvement of strength and plasticity during rolling， the microstructure refinement resulted in a 45% increase in the tensile strength of the finished wire rod compared to the casting billet. From casting billet to finished wire rod， the interlayer spacing has been refined by 76%， and the pellet size has been refined by 78%. During the entire rolling process， the contribution of pearlite interlayer spacing and pellet size to yield strength were 80% and 20%， respectively. The precipitated phases were mainly carbides of Ti and V， and due to the high temperature during the hot rolling process， the some precipitated phases in the middle of the cast billet underwent dissolution and re-precipitation， resulting in a smaller number and size of precipitated phases in the wire rod.关键词：Bridge Cables;92Si wire rod;Hot-rolling;Evolution of Microstructure and Properties147|5|0更新时间：2025-05-09
- 摘要：The short-process manufacturing technology of Cr12MoV cold work die steel， involving "90-ton ultra-high power electric arc furnace smelting → LF+VD refining → arc continuous casting → one-step hot rolling of continuous casting billet"， has been successfully industrialized production. However， the Cr12MoV flat steel products with a thickness greater than 50 mm produced by this process exhibit a high level of carbide network， which adversely affects the machining and use performance of the molds. To address this issue， this study systematically analyzes the effects of heating temperature and deformation temperature on the morphology of carbides using Gleeble thermal simulation experiments and simulation technology. The results indicate that appropriately increasing the heating temperature facilitates the dissolution of carbides， although excessively high temperatures can reduce the plasticity of the material. While the deformation temperature has an insignificant impact on the carbide morphology， enhancing the penetration of deformation into the interior of the flat steel can effectively improve the distribution of carbides. In industrial production practice， implementing a high-temperature diffusion process at heating temperature 1 170 ℃ for 5 hours， combined with controlled rolling in the first four passes， with the carbide non-uniformity rating improving from level 4 to level 2， significantly improved the carbide quality of the finished flat steel.关键词：Cr12MoV Continuous-casting Billet;Flat Bar;High-temperature Diffusion;Temperature-controlled Rolling;Carbide6|4|0更新时间：2025-05-09
Forming and Phase Transition
- 摘要：In pure hydrogen pipeline systems， the transmission pressure is critical for ensuring both efficient operation and safety performance. Through the slow tensile and fatigue life tests under high pressure gas phase environment， the influence law of plasticity and fatigue life properties under different hydrogen partial pressure on X52M pipeline steel （mass fraction /%： 0.04C，0.98Mn，0.010P，0.001S，0.033Nb，0.033V，0.16Cr，0.014Ti） were contrastive studied， Various characterization techniques， including metallographic microscopy and scanning electron microscopy （SEM）， were utilized to examine the microstructural evolution and fracture mechanisms. The results indicated that the loss rate of slow tensile section shrinkage increased significantly with the increasing of hydrogen partial pressure， the ductility loss was measured to be 10.5%， 17.5%， and 28.5% under 4 ， 6 ，10 MPa hydrogen pressure， respectively. Furthermore， hydrogen partial pressure significantly impacted the fatigue life of the material. A substantial increase in fatigue life reduction from 37.1% to 63.1% was observed when the hydrogen pressure was raised from 6 MPa to 10 MPa， indicating a heightened susceptibility to hydrogen embrittlement. The increase in the partial pressure of hydrogen leads to more hydrogen-induced cracks， which are difficult to crack in the hydrogen environment， and eventually leads to more serious hydrogen brittlement of the material. The test results can be used as an important reference basis for hydrogen transmission pipeline design and safe operation.关键词：Hydrogen Transportation Pipeline;High-pressure Hydrogen;Gas Transportation Pressure;Slow Tensile;Fatigue Life5|15|0更新时间：2025-05-09
- 摘要：Using optical microscope， scanning electron microscope， and dilatometer etc， this work investigated the effects of alloy elements Nb and V on the austenite microstructure and expansion property of 4J32 alloy. The results indicated that when the addition amount of Nb was 0.1%， the pinning effect on the austenite grain boundaries was not apparent， and abnormal grains growth occurred in the specimens. However， when the addition amounts of Nb reached 0.3% and 0.4%， the microstructure of the specimens was homogeneous， and the average grain sizes decreased by 24.6% and 32.3%， respectively.When the addition amounts of V reached 0.3% and 0.4%， the grain sizes decreased by 14.4% and 16.3%， respectively. The refining ability of Nb on the austenite grains and the homogenization ability of the microstructure of the super Invar alloy were superior to those of V. When the addition amount of Nb reached 0.4%， NbC was mainly distributed along grain boundaries. When the addition amount of Nb was less than 0.4%， NbC distributed in a small amount within grains. The number and size of NbC precipitates increase with the increase in the Nb content. The average linear expansion coefficient α20-100 ℃≤1.0×10-6/℃ of the experimental alloys with the addition of Nb and V met the application requirements. Overall， the alloys with the addition amounts of 0.3% for both Nb and V showed a more appropriate combination of microstructure homogeneity， grain refinement， and expansion coefficient.关键词：Super Invar Alloy;Nb and V Microalloying;Homogenization of Structure;Expansion Coefficient4|3|0更新时间：2025-05-09
- 摘要：The wire cutting and corrosion of the three-pins shaft part were carried out， and the microstructure observation results showed that there was severe mixed crystal phenomenon in the area with the highest cold deformation rate of the three-pins shaft head. Through in-depth exploration of this phenomenon， it was analyzed that the reason for mixed crystals in this area is due to the significant deformation experienced on both sides of the shaft head during the cold extrusion process of the three-pins shaft. During the high-temperature carburizing process， small grains fused with each other， ultimately forming coarse grains. In order to eliminate coarse grains on both sides of the shaft head of the three pin shaft component， different normalizing and annealing pretreatment processes were adopted to cause a large amount of AlN compounds in the material to precipitate again and form segregation at the grain boundaries， forming new AlN precipitates that play a strong role in pinning the grain boundaries. The normalizing and annealing pretreatment processes with different process parameters can improve the austenite grain size of the three-pins shaft parts to varying degrees. The best pretreatment scheme for improving the effect is the pre normalizing process above 900 ℃. The adoption of this scheme can improve the grain size of the three-pins shaft parts that were originally severely mixed， and the grain size of the three-pins shaft parts can reach 7.0 or above.关键词：Three-pins Shaft;Grain;Normalizing;Annealing6|1|0更新时间：2025-05-09
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