Properties Of Steel Research Articles

Effect of Laser Selective Melting on the Microstructure and Properties of Martensitic Stainless Steel After Annealing Treatment

This work investigated the 0Cr16Ni5Mo1 stainless steel using laser selective melting (SLM) technology and explored the effect of the tempering temperature on the microstructure and properties. After the tempering treatment, the quenched martensite transformed from a metastable to steady state, and residual austenite was formed. The results indicated that the elongation of the transverse specimen showed an upward trend as the tempering temperature increased, while the elongation of the longitudinal specimen first increased and then decreased. The fracture mode was ductile. There was an obvious fiber, radial, and shear lip zone on the fracture surface of transverse specimens. When the tempering temperature was 650 °C, the shear lip area of the fracture surface was the largest. For longitudinal specimens, there was no obvious zoning on the fracture surface.

Interaction mechanism of dislocations with Bi/hBN nanoparticles in free-cutting steels: molecular dynamics simulations

Abstract To further understand the mechanical properties of free-cutting steels, we employed molecular dynamics (MD) simulations to investigate the interaction mechanisms between dislocation slip along close-packed planes and nano-inclusion particles (Bi/h-BN) within single-crystal iron (Fe). By colliding dislocations at varying slip velocities with nanometer-scale particles of different sizes and compositions, we concluded that particle diameter plays a decisive role not only in determining the dislocation cutting mode but also in influencing the dislocation’s shear stress response. These indicate that: Larger particles significantly enhance the strengthening effect on the matrix. Additionally, higher dislocation slip velocities result in stronger particle interaction feedback and greater particle damage, contributing to increased matrix deformation. h-BN particles, owing to their much higher hardness compared to Bi, exhibited superior resistance to deformation, requiring higher dislocation shear stress to pass these obstacles.

Research Progress on Titanium–Niobium Micro-Alloyed High-Strength Steel

Research on micro-alloyed steel is a strategic measure to meet the needs of various industries and promote green development, and it is essential for many major steel-producing countries. Currently, the mainstream micro-alloying elements in the research and application of micro-alloyed steel are V, Ti, and Nb. Due to the high price of V, the actual production is mostly achieved by adding titanium–niobium composite to change the properties of high-strength steel. This article begins by examining the strengthening mechanisms in titanium–niobium micro-alloyed high-strength steel. It then reviews the literature on how metallurgical processes and second-phase particles affect the steel’s properties. The article summarizes the current research status and analyzes the problems in the existing research process and results. Finally, it explores future research directions, offering insights into subsequent studies and applications.

Numerical evaluation of the internal fracture mechanism of horizontal loop connections in precast elements under the influence of transverse reinforcement

AbstractThis study numerically evaluated the flexural capacity and fracture mechanism of precast reinforced concrete beams connected with in situ horizontal loop connections employing the three‐dimensional rigid body spring model (3D‐RBSM) for modeling of concrete and beam elements (BEs) for modeling of steel, respectively. The research analyzed the performance of continuous horizontal loop connections with and without transverse reinforcement, considering varying vertical spacing between loops and transverse steel ratios. The numerical model effectively captured the test load displacement relationships by incorporating the model parameters like Young's modulus, tensile strength, fracture energy, compressive strength, cohesion, and angle of internal friction for concrete along with mechanical properties of steel and revealed that loop joints without transverse reinforcement exhibited loop type failure. In contrast, specimens with transverse reinforcement improved the peak load and caused compression failure. It was discovered that transverse rebars on the continuous side of the joint experience more strain; particularly, the maximum strain occurred in the corner rebars within the curved sections of U‐rebars. Moreover, the increased vertical spacing between the loop rebars increased the diagonal crack propagation and demonstrated the loop‐type failure. Further, a larger circumferential area of transverse rebar offered greater bond strength and confinement to the concrete core and reproduced the maximum deformation capacity, ductility, and compression failure.

Application of Surface-Cracking Process to Improve Impact Toughness of High-Strength BCC Steel at Low Temperatures

At very low temperatures, typically ductile materials, especially body-centered cubic (BCC) steels, often exhibit an abrupt transition to brittle fracture, significantly limiting their applicability in cryogenic and low-temperature environments. This challenge arises from the inherent properties of BCC steels, where ductility is drastically reduced, leading to unexpected failures under mechanical stress. Despite the advantages of high-strength BCC steels, including cost-effectiveness and mechanical robustness, their susceptibility to brittle fracture restricts their use in demanding low-temperature applications. To address this limitation, we developed an innovative surface-cracking process to enhance the impact toughness of BCC steels. The introduction of controlled surface cracks redistributes stress and energy dissipation mechanisms, improving the toughness of high-strength BCC steels at cryogenic temperatures. Microscopic observations and finite element analyses reveal that these surface cracks not only dissipate crack formation energy but also alter stress triaxiality at crack tips. This causes the stress state to transition toward a plane stress condition, effectively mitigating stress concentrations typically observed in plane strain states. By reducing localized stress severity and promoting uniform energy distribution, the surface cracks encourage failure mechanisms favoring ductile behavior over brittle fracture.

Microstructure and mechanical properties of Y-modified low-activation austenitic steel after aging

Microstructure and mechanical properties of Y-modified low-activation austenitic steel after aging

Tempering Temperature Effect on the Static and Impact Properties of 51CrV4 and 55Cr3 Spring Steels

Tempering Temperature Effect on the Static and Impact Properties of 51CrV4 and 55Cr3 Spring Steels

Annealing effect on structure, phase composition and mechanical properties of high-nitrogen austenitic steel

Annealing effect on structure, phase composition and mechanical properties of high-nitrogen austenitic steel

Scan Strategy Effect on the Mechanical Properties and Microstructure of Directed Energy Deposited 18Ni300 Maraging Steel

Although the laser scan strategy does not affect the energy density of laser-based additive manufacturing, changes in laser scan direction critically influence the residual stress and microstructure of metallic components. However, only a limited number of studies have investigated the role of laser scan strategy on the microstructure and mechanical properties of additively manufactured maraging steels. Therefore, this study examines the effect of laser scan strategy on the mechanical properties of 18Ni300 maraging steel. Different laser scan strategies influence the morphologies of the molten pool, where retained austenite is concentrated in 18Ni300 maraging steel. The 45o sample exhibits a denser molten pool distribution compared to the other samples due to reduced layer overlapping. Because of the plastic strain incompatibility between martensite and austenite at the molten pool boundary, this dense molten pool distribution in the 45o sample resulted in the highest back-stress hardening. Additionally, the minimal layer overlapping in the 45o sample reduces heat exposure during laser-based additive manufacturing, leading to a finer martensite block and lath size. By combining high back-stress hardening with a fine martensite block and lath size, the 45o sample achieved the highest tensile property compared to the other samples. These results indicate that the selection of laser scan strategy is crucial for designing a heterogeneous microstructure in additively manufactured parts, which can enhance mechanical properties, even with the same energy density.

Precipitation-controlled grain boundary engineering in a cast & wrought Ni-based superalloy

Grain boundary engineering (GBE) describes the various approaches to control the fraction and composition of special boundaries in designing engineering materials. For example, complex thermo-mechanical processing routes are harnessed to increase the fraction of Σ3 twin boundaries, bringing about improvements to strength, toughness, and corrosion properties in austenitic stainless steels. However, high-temperature gas turbine engine components designed for the most demanding applications must be manufactured from Ni-based superalloys. To provide the required high-temperature strength, their microstructures are highly complex and consist of an austenitic γ-matrix, γ' precipitates, and grain boundary (GB) carbides, and/or borides. GBE approaches for Ni-based superalloys have been reported to reduce in-service GB cracking via targeted engineering of the GB microstructure. However, the same complex microstructures severely limit the processability of the most advanced Ni-based superalloys required to develop the next generation gas turbine engines.To tackle this challenge, we propose precipitation-controlled GBE for Ni-based superalloys with limited formability, via formation of GB serrations and precipitation upon slow cooling. We showcase our approach by achieving controlled GB precipitation of GB-γ' and M6C carbides in the cast & wrought Ni-based superalloy René 41 via a simple heat treatment. Ductility improvements are predicted via crystal plasticity modeling due to increased slip transmission compatibility. Instead of generating additional Σ3 twin boundaries only, these interfaces are directly incorporated into the GB network. It is shown that precipitation-controlled GBE is enabled by GB-γ' nucleating heterogeneously on M6C whereby competitive coarsening of GB-γ' provides the driving force. The fundamental mechanisms of our GBE approach are discussed and summarized in a qualitative microstructural model.

Strengthened microstructure and mechanical properties of austenitic 316L stainless steels by grain refinement and solute segregation

Strengthened microstructure and mechanical properties of austenitic 316L stainless steels by grain refinement and solute segregation

Effects of continuous cooling and isothermal cooling parameters on microstructure and mechanical properties of EH420 marine steel

Effects of continuous cooling and isothermal cooling parameters on microstructure and mechanical properties of EH420 marine steel

Effect of laser surface remelting on the microstructure and properties of high manganese steel coating

Effect of laser surface remelting on the microstructure and properties of high manganese steel coating

Microstructure structure and mechanical properties of ultrahigh strength maraging stainless steel strengthened by coherent precipitation

Microstructure structure and mechanical properties of ultrahigh strength maraging stainless steel strengthened by coherent precipitation

Effects of ultrasonic impact treatment on the tensile properties of DH36 steel welded joints

Effects of ultrasonic impact treatment on the tensile properties of DH36 steel welded joints

Effect of soaking temperature and baking process on the microstructure and mechanical properties of novel press-hardened steel

Effect of soaking temperature and baking process on the microstructure and mechanical properties of novel press-hardened steel

Effect of aging at 700°C on the microstructure, phase transformations, and mechanical properties of low-activation austenitic steel

Effect of aging at 700°C on the microstructure, phase transformations, and mechanical properties of low-activation austenitic steel

Dual-interfacial alloying mechanism in Ti-steel laminated metal composite fabricated by wire-arc directed energy deposition using a Cu-Ni interlayer

Ti-steel laminated metal composites have been widely used in shipbuilding and the chemical industry due to the superior corrosion resistance of Ti and the favorable mechanical properties of stainless steel. In this paper, Ti-steel laminated metal composites without Ti-Fe IMCs have been fabricated by directed energy deposition-arc method using a Cu-Ni transition interlayer. Based on the analysis of microstructure analysis, the cross-sectional microstructure can be divided into 304SS / Cu-Ni interface containing (Fe, Cr) and (Cu) solid solution, Cu-Ni deposition layer containing (Fe, Cr) and (Cu) solid solution, and TA2/Cu-Ni interface containing Ti2FeCu and Ti-Cu IMCs. Besides, the Cu-Ni deposition layer contains a small content of recrystallized grains with {100}<100> texture and a large content of deformed grains with{100}<110> texture due to the impact of arc and droplets during continuous depositions. Furthermore, the peak hardness is decreased to 518 Hv and the mean value of compressive shear strength is enhanced to 195.27MPa, which can be attributed to the elimination of interfacial Ti-Fe IMCs, defect-free microstructure, and residual stress relief. Based on polarization curves and electrochemical impedance spectroscopy, the corrosion resistance reduction of the cross-section is due to the formation of a mass of primary battery systems. Furthermore, based on the thermodynamics calculation of Fe-Cu-Ni, Ti-Fe-Cu, and Ti-Ni-Cu ternary systems, the alloying mechanism is that Ti-based IMCs with lower Gibbs free energy will be formed instead of brittle Ti-Fe IMCs, resulting in the elimination of Ti-Fe IMCs and the formation of less brittle phases at both 304SS / Cu-Ni interface and TA2 / Cu-Ni interface.

Impact of the oxide layer and subsurface micromechanical properties of laser peened 31L stainless steel on biocorrosion resistance in simulated body fluid

Impact of the oxide layer and subsurface micromechanical properties of laser peened 31L stainless steel on biocorrosion resistance in simulated body fluid

Tailoring the mechanical property and sulfide stress corrosion cracking resistance of rare earth doped casing steel by tempering treatment

Tailoring the mechanical property and sulfide stress corrosion cracking resistance of rare earth doped casing steel by tempering treatment