The strength of Q690DR steel decreases with the increase of tempering temperature, and the -40 ℃ impact toughness increases with the decrease of quenching temperature, and the increase of tempering temperature between 640-680 ℃. Controlling the heat treatment condition, it can ensure the steel meets engineering application requirements for new high-pressure hydrogen storage vessels. Through the slow strain rate tensile test with electrochemical dynamic hydrogen charging, the elongation rate of Q690DR was reduced by 3%, and the area shrinkage was reduced by 14.1%, compared with the tensile test results under air condition. It showed that Q690DR has a low susceptibility to hydrogen embrittlement under such condition. The hydrogen desorption curves of Q690DR under different heating rates, placement times, and hydrogen charging current densities were tested through thermal desorption sepctrometry TDS. The low-temperature hydrogen desorption activation energy of Q690DR was calculated to be Ea=13.39 kJ/mol, and the high-temperature hydrogen desorption activation energy of Q690DR was calculated to be Eb=117.51 kJ/mol. The hydrogen diffusion coefficient of Q690DR is 9.85×10^-7 cm²/s. After hydrogen charging, the diffusible hydrogen in the matrix can escape completely after being holding for more than 12 hours. The hydrogen content charged in the Q690DR matrix increases with the increase of hydrogen charging current density. In addition, with the help of atomic force microscope AFM, we observed the enrichment behavior of hydrogen in the grain boundaries and the second phase after hydrogen charging. Based on the changes in potential difference, we can judge that the grain boundaries are shallow hydrogen traps and the second phase is deep hydrogen traps.

With the rapid progress of China′s power electronics and new energy industries, the demand for efficient, multi-purpose and environmentally friendly soft magnetic alloys is also gradually increasing. Existing research situation on the performance regulation of silicon steel is discussed. Based on the characteristics of the soft magnetic material, we points out the core performance index of iron loss, and points out the necessity of improving the resistivity of the material through composition regulation and other means, so as to achieve the maximum energy efficiency. Secondly, the influence of alloy composition, inclusion, defect, grain size, residual stress and crystal structure on the performance of silicon steel is discussed. In addition, we points out that with the progress of material science and nanotechnology, the research on the relationship between microstructure and performance of silicon steel will be more in-depth, and people will be able to more precisely regulate silicon steel in order to achieve better magnetic performance.

Review of casting magnesium alloys containing Nd is performed. In terms of the microstructure, mechanical properties and corrosion resistance, the effect of Nd on the grain size and second phase precipitation of magnesium alloys is analyzed, the influence of Nd on the ultimate tensile strength, yield strength and elongation of magnesium alloys is discussed, and the effect of Nd on the corrosion resistance of magnesium alloys is reviewed, with the aim of providing references for the design and development of casting magnesium alloys containing Nd.

Refining grain size can effectively enhance the coercivity of bulk sintered NdFeB permanent magnets while ensuring high uniformity in magnetic properties. Key steps for grain refinement in sintered NdFeB magnets and current industrial equipment status had been described. During rapid solidification, high cooling rates effectively suppress α-Fe phase formation and reduce fragmentation difficulty. For cerium-rich magnets, trace additions of co-associated rare earth elements like La and Y help decrease the growth width of rapidly solidified flakes. Quantification of liquid volume per unit time during production proves crucial for structural consistency in rapid-solidified products. In powder preparation, regulation and adaptive control of hydrogen decrepitation process achieve preliminary powder refinement. Different jet mill configurations exhibit distinct characteristics, with fluidized bed jet mills being the most prevalent equipment, where airflow velocity at nozzle intersections in grinding chambers determines powder refinement efficiency. Regarding sintering, beyond conventional processes, spark plasma sintering emerges as an effective approach for achieving densification and suppressing abnormal grain growth. For powders with particle sizes below 2 μm, pressureless forming technology successfully resolves the forming challenges inherent to ultrafine powders.

High purity dysprosium and terbium metals serve as the fundamental raw materials in various fields, including permanent magnet materials, magnetostrictive materials, magneto-optical storage materials, magnetic refrigeration materials and electric light source materials. The calcium thermal reduction method and the intermediate alloying method used in the preparation of industrial pure dysprosium and terbium metals are summarized, and the vacuum distillation method, zone melting method and solid state electromigration method are described in detail. The technology of hydrogen ionization arc melting, electrochemical deoxidation and solid phase external inspiratory are also summarized. Finally, we considers the future development direction of high purity dysprosium and terbium metals from the perspective of market orientation and operability, and provides reference for the development of high purity rare earth metals dysprosium and terbium industries.

This study investigates the changes in microstructure, mechanical properties, and frequency-temperature coefficients of 3J33B high-elasticity alloy under different aging heat treatment conditions. As a significant material in aerospace and precision instruments, the 3J33B alloy exhibits an ultra-low carbon martensitic structure in its solution-treated state, which can reversibly transform into austenite after aging treatment, significantly affecting its physical and mechanical properties. By systematically adjusting the aging temperature and duration, the study found that aging treatment not only promotes the precipitation of nanoscale γ′ strengthening phase, enhancing the alloy's strength, but also regulates the alloy′s toughness and frequency-temperature coefficient through the formation and growth of reversed austenite. The tensile strength of the alloy reaches its peak of 2 173 MPa at 500 ℃ aging, while the frequency-temperature coefficient is minimized at 625 to 650 ℃ aging, approximately (10-20)×10^-6/℃. These findings provide a theoretical basis and optimization direction for the application of 3J33B alloy in high-precision navigation systems.

To solve the problem of fluctuations in the impact toughness of A516 Gr.70 low-alloy steel plates with a thickness of 60 mm after welding and post-weld heat treatment, a thermal simulation experiment was conducted. The main reason for the fluctuations in hardness and impact properties of the steel plates in the as-rolled and welded states was found to be the presence of obvious coarse spherical pearlite organization in the near surface layer. By optimizing the temperature regime of the heat treatment furnace and adding a post-furnace air cooling device, the impact toughness of the low-alloy steel plates for low-temperature pressure vessels delivered in the normalized condition was significantly improved, with the pass rate increasing from 81.27% to 96.27%.

Much lower mass fraction of manganese for high silica pure iron for amorphous master alloy is necessary. The technology for the production of high silica pure iron using the long process of "KR desulfurization of molten iron → LF deep desulfurization of molten iron → BOF smelting → LF refining → RH vacuum refining → slab continuous casting", was developed by assessing the capacity of demanganization of 180 t BOF and LF/RH ladle refining furnace and analyzing the scientific principle demanganization. By choosing the molten iron of low manganese, operating double slag at the moment of 30%-35% of blowing oxygen and 1 350-1 400 ℃ of molten bath, pouring out slag amount of 70%-80%, controlling oxygen content of final slag is more than 0.070 0% and tapping temperature vary from 1 610 to 1 625 ℃, improving the basicity of LF slag at 6.5 and so on, which can achieve the production of the steel containing manganese with the mass fraction of less than 0.025% and w(Fe) and w(Si) are equal to 99.90% or larger, meet the requirement of the low manganese and high silica pure during the mass production.

Taking the ZTH-200 clamp-type square cone NdFeB mixer as the research object, a calculation model of NdFeB powder mixing was established based on EDEM finite element analysis software. Material properties are defined in the simulation, and boundary conditions are loaded, solved and post-processed. The effects of different fill volumes and different mixer rotation speeds on mixing efficiency and uniformity were analyzed. The simulation results showed that 50% of the powder loading volume has the highest mixing efficiency. Appropriately increasing the powder mixing speed can improve the uniformity of magnetic powder mixing. If the powder mixing speed is low, the mixing time should be increased appropriately.

Using tungsten argon arc welding to prepare ER308L stainless steel deposited metal, and the effects of solution treatment at 1 050 ℃ for 2 hours on its microstructure and high-temperature tensile properties at 350 ℃ were studied. The results show that solid solution treatment promotes the partial dissolution of δ ferrite into γ austenite, reduces the δ/γ phase interface, simplifies the complex dislocation structure, and transforms the columnar grains of austenite into smaller equiaxed ones. The average grain size decreased from 384 to 81 μm. Solid solution treatment also reduces the ferrite content from 12.2% to 4.88%, and changes the morphology from skeleton and lath to granular, making the structure more susceptible to yield deformation. These changes significantly improve the high-temperature plasticity of the deposited metal and reduce the yield strength. After solution treatment, the high-temperature elongation of the deposited metal increased from 29% to 38%, the yield strength decreased from 322 to 128 MPa, and the hardness decreased from 210 to 138 HV₅.

DPF catalyst is an exhaust after-treatment technology applied to diesel engines. It can effectively reduce particulate matters in exhaust gas. In recent years, it has been widely used in commercial vehicles, engineering/agricultural machinery, ships, and other fields. In the early days, the wall-flow honeycomb ceramic substrates production technologies are basically monopolized by foreign manufacturers. Recently, however, domestic manufacturers have made great progress in related technologies. The product has caught up with foreign competitive products. Several DPF substrates are selected from domestic manufacturers and the comprehensive performance are fully studied comparing with the ones from foreign competitors.

The production process of low-alloy steel is relatively simple, the cost is not high, and its wear resistance and toughness are good, suitable for mechanical engineering fields such as excavator buckets. When the bucket is in direct contact with the material during excavation operations, it will cause serious wear and tear. In order to increase the strength and wear resistance of the bucket, and to improve the strength and wear resistance of the bucket, the chemical composition of the bucket tooth steel was improved, and the sprue and riser of the casting system were optimized and designed. The experimental results show that the wear amount of the newly designed bucket tooth side plate in the height direction is only 55.0%, 54.0%, and 57.1% of YNM400 steel, which is about half of the wear amount of YNM400 steel. The wear resistance has been significantly improved, and no phenomena such as detachment or cracking occurred during the testing process, which meets the weldability standards. The use of this new type of steel can improve the performance of excavators, which is of great significance for the development of the excavator industry.

Through systematic regulation of heat treatment temperatures, this study comprehensively investigates the effects of different thermal processing conditions on the soft magnetic properties, thermal expansion behavior, and microstructural evolution of a 0.3% Nb-containing FeNi₃₂Co₅ Super-Invar alloy. Experimental results demonstrate that the alloy subjected to 1 150 ℃ heat treatment exhibited the optimal overall performance. Post-treatment microstructural characterization revealed coordinated grain growth and optimized distribution of secondary phases, which synergistically enhanced the soft magnetic characteristics. Specifically, the magnetic permeability parameters showed significant improvements with μ0.4, μ_m, and Bs reaching 3.910 mH/m, 5.903 mH/m, and 1.279 T respectively, while residual induction (B_r) and coercivity (H_c) were reduced to 0.412 6 T and 13.71 A/m. Crucially, the alloy maintained its intrinsic low thermal expansion characteristics with a coefficient of thermal expansion (α) below 0.3×10^-6 /K. This optimized thermal-mechanical treatment protocol achieved remarkable enhancement in the comprehensive performance metrics of the super-invar alloy system, demonstrating exceptional balance between magnetic functionality and dimensional stability.

Nickel based single crystal high-temperature alloys are widely used in high-temperature working environments such as aviation engines, and their performance directly affects the reliability and lifespan of the engine. Laser shock, as a surface modification technique, can effectively improve the properties of metals. To investigate the effects of laser shock technology on the phase structure, microhardness, residual stress, friction and wear properties, and oxidation resistance of nickel based single crystal high-temperature alloys, experiments were conducted using equipment such as X-ray diffractometer, hardness tester, X-ray stress analyzer, and material surface performance comprehensive tester. The experimental results showed that after being subjected to laser shock, the volume fraction of the γ′ phase in the alloy was 72.6%, which increased by 15.2% compared to before laser shock. The phase composition of the alloy after laser shock did not change, the diffraction peak intensity gradually decreased, the microhardness showed an increasing trend, the residual stress on the alloy surface significantly increased, the friction coefficient gradually decreased with the increase of laser energy shock, and the oxidation resistance of the alloy was significantly improved. The experimental results indicate that laser shock technology can be used to improve the properties of nickel based single crystal high-temperature alloys, significantly enhancing their mechanical properties and fatigue life.

Undercut is one of the key factors limiting the iterative upgrading of etched metal lead frames, and attenuating or eliminating the undercut is a common challenge faced by etch engineers, equipment manufacturers, and potion developers. Copper corrosion inhibitors as an anti-undercut additive were added to the acidic copper chloride etchant. Based on the principle of anti-undercut additive, the effective anti-undercut additive and its use of the concentration were screened out through the static and dynamic etching experiments. Finally, a kind of lead-frame product was used to verify the improvement effect of anti-undercut additive on the uniformity of etching size. It provides a feasible method for the improvement and enhancement of the etching process in the metal lead frame industry, and at the same time fills the research gap of anti-side-etching agents in the metal lead frame industry.