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Steels are ubiquitous due to their affordability and the landscape of useful properties that can be generated for engineering applications. But to further expand the performance envelope, one must be able to understand and control microstructure development by alloying and processing. Here we use multiscale, advanced characterization to better understand the structural and chemical evolution of AISI 4340 steel after quenching and tempering (Q&T), including the role of quench rate and short-time, isothermal tempering below 573 K (300 °C), with an emphasis on carbide formation. We compare the microstructure and/or property changes produced by conventional tempering to those produced by higher temperature, short-time “rapid” tempering. We underscore that no single characterization technique can fully capture the subtle microstructure changes like carbon redistribution, transition carbide and/or cementite formation, and retained austenite decomposition that occur during Q&T. Only the use of multiple techniques begins to unravel these complexities. After controlled fast or slow quenching, η transition carbides clearly exist in the microstructure, likely associated with autotempering of this high martensite start temperature (Ms) steel. Isothermal tempering below 598 K (325 °C) results in the relief of carbon supersaturation in the martensite, primarily by the formation of η transition carbides that exhibit a range of carbon levels, seemingly without substitutional element partitioning between the carbide and matrix phases. Hägg transition carbide is present between 300 °C and 325 °C. After conventional tempering at or above 598 K (325 °C) for 2 h, cementite is predominant, but small amounts of cementite are also present in other conditions, even after quenching. Previous work has indicated that silicon (Si) and substitutional elements partition between the cementite, which initially forms under paraequilibrium conditions, and the matrix. Phosphorous (P) may also be preferentially located at cementite/matrix interfaces after high temperature tempering. Slower quench rates result in greater amounts of retained austenite compared to those after fast quenching, which we attribute to increased austenite stability resulting from “autopartitioning”. Rapid, high temperature tempering is also found to diminish tempered martensite embrittlement (TME) believed to be associated with the extent of austenite decomposition, resulting in mechanical properties not attainable by conventional tempering, which may have important implications with respect to industrial heat treatment processes like induction tempering. Controlling the amount and stability of retained austenite is not only relevant to the properties of Q&T steels, but also next-generation advanced high strength steels (AHSS) with austenite/martensite mixtures.

We present Uncertainty-Weighted Contrastive Fusion (UWCF), an algorithmic framework for robust 6-DoF pose estimation under occlusion and sensor noise. UWCF couples pixel-wise uncertainty inferred from temporal photometric consistency, instance-dependent contrastive tempering and spatial reweighting, and an uncertainty-gated RGB-D fusion with uncertainty-masked refinement. We provide a theoretical analysis showing that uncertainty-driven temperature scaling and weights reduce the bias induced by instance-dependent corruption and decrease gradient variance in InfoNCE. On public RGB-D pose benchmarks and controlled corruption suites, UWCF consistently improves ADD/ADD-S and calibration metrics (ECE, NLL, AUSE) over recent fusion and contrastive baselines, while maintaining competitive throughput [1, 2] . Extensive ablations isolate the contribution of uncertainty estimation, contrastive tempering, and gating. These results indicate that explicitly modeling uncertainty to modulate cross-modal alignment is a principled and effective route to robust 6-DoF pose estimation beyond a specific application domain.

Probes are an important tool for testing electrical functional defects in integrated circuits (ICs). As the critical size of ICs continue to shrink, the process quality requirements for IC test probes are also getting higher and higher. Therefore, exploring the precision manufacturing of probes to improve their product yields has become a very important topic and goal in the current IC test industry. Although probes manufactured in IC testing have shown electrical quality characteristics with highly correlated responses, there is currently little research into effective solutions to the impact of their dimensions and criteria (process factors). This study uses the Decision Making Trial and Evaluation Laboratory (DEMATEL) to analyze the criteria that affect the yield of IC test probes and the causal relationships between dimension/criteria, and uses an IC test probe manufacturer as a case study. Research results show that design (A) is the core dimension. Among the overall 24 criteria, plunger (A2) and spring design (A3) are the core criteria that improve the yield of IC test probe processes. The second order is component size (E2), machine warm-up (B1), electroplating solution concentration (D6), temperature of tempering furnace (C4) and roughness of turned parts (B4).

Sulfide stress cracking (SSC) failure is a main concern for the pressure vessel steel Q345 used in harsh sour oil and gas environments containing hydrogen sulfide (H2S). Methods used to improve the strength of steel usually decrease their SSC resistance. In this work, a quenching and tempering (Q&T) processing method is proposed to provide higher strength combined with better SSC resistance for hot-rolled Q345 pressure vessel steel. Compared to the initial hot-rolled plates having a yield strength (YS) of ~372 MPa, the Q&T counterparts had a YS of ~463 MPa, achieving a remarkable improvement in the strength level. Meanwhile, there was a resulting SSC failure in the initial hot-rolled plates, which was not present in the Q&T counterparts. The SSC failure was not only determined by the strength. The carbon-rich zone, residual stress, and sensitive hardness in the banded structure largely determined the susceptibility to SSC failure. The mechanism of the property amelioration might be ascribed to microstructural modification by the Q&T processing. This work provides an approach to develop improved strength grades of SSC-resistant pressure vessel steels.

In this paper, we investigated the effects of the matrix and precipitates in Cr-Ni-Mo-V rotor steel on its mechanical properties after water quenching and tempering (450–700 °C). The results indicate that the microstructure and mechanical properties of the steel can be significantly adjusted by changing the tempering temperature. An excellent combination of tensile strength (1028.608 MPa) and elongation (19%) was obtained upon tempering at 650 °C. This is attributed to the martensite lath with a high dislocation density, solid solution strengthening and the strengthening effect of spherical Mo2C and VC particles. At a tempering temperature of 550 °C, the precipitation and development of rod-shaped Fe3Mo3C resulted in a considerable drop in strength. At 650 °C, the dissolution of Fe3Mo3C and dispersion precipitation of Mo2C and VC led to a large rise in strength. At 700 °C, the coarsening of Mo2C and VC, together with the recrystallization of the martensite lath, resulted in a loss in strength. Meanwhile, as the tempering temperature was increased from 450 °C to 700 °C, the tensile fracture characteristics of Cr-Ni-Mo-V rotor steel gradually changed from cleavage fractures to dimple fractures.

This study systematically investigates the influence of quenching (850–910 °C) and tempering (160–280 °C) temperatures on the microstructural evolution and mechanical properties of a novel low-alloy ultra-high-strength martensitic steel (UHSMS). Comprehensive microstructural characterization combined with mechanical testing demonstrates that quenching at 880 °C results in the finest martensitic laths and the highest dislocation density, leading to an excellent strength–toughness balance. Subsequent tempering treatments reveal that the specimen tempered at 200 °C achieves an optimal combination of properties, with a yield strength of 1517 MPa, ultimate tensile strength of 2017 MPa, elongation of 10.4%, and impact toughness of 80.3 J/cm2. This optimum is mechanistically linked to a cooperative effect where the fine tempered martensitic structure and stable film-like retained austenite (RA) enhance toughness and ductility, while the nano-scale precipitates (forming during the ε→θ carbide transition) simultaneously provide substantial precipitation strengthening, thereby minimizing the strength sacrifice typically associated with improved toughness. Furthermore, the 200 °C tempered specimen exhibits the largest shear lip on the tensile fracture surface and the maximum dimple size on the impact fracture surface, indicative of a high plastic strain capacity and excellent crack propagation resistance.

14Cr17Ni2 is a martensitic stainless steel with good matching of strength and toughness. Its mechanical properties depend on quenching and tempering process, especially tensile strength and impact toughness require appropriate heat treatment process to achieve the mechanical properties required by design. In order to solve the problem that the impact energy is difficult to reach the standard, this paper studies the relationship between the temperature time of quenching and tempering and the microstructure and properties, and obtains that the hardness of HBW328 can meet the requirements when the quenching temperature is 950 °C and the tempering temperature is 600 °C, so as to realize high-efficiency and high-quality processing of turning and tooth making.

This research studies the influence of the copper alloying of medium-carbon steel on mechanical properties after quenching and tempering at 500 °C. The microstructure was characterised using SEM, EBSD, TEM, and XRD analysis. The mechanical properties were comprehensively investigated using hardness measurements, tensile and Charpy impact tests and solid solution, grain boundary, dislocation, and precipitation strengthening contributions were estimated. Higher yield strength for Cu-alloyed steel was confirmed at about 35–73 MPa. The precipitation strengthening contribution from Cu precipitates in the range of 11–49 MPa was calculated. The interaction between Cu precipitates and dislocations retards the decrease in dislocation density. Similar values of effective grain size of martensite crystals were measured for Cu-alloyed and Cu-free steel as well. Copper alloyed steel exhibited significantly deteriorated impact toughness, total plastic elongation, and reduction of area. The size of Cu precipitates ranged from 8.3 nm after tempering at 500 °C for 6 h to 13.9 nm after tempering for 48 h.

Quenching and tempering treatment experimentswere conducted on the bimetallic band saw blades,and theeffect of quenching and tempering processes on the microstructure and properties of the band saw blades were studied. The results indicate that with increasing quenching temperature, the solid solution strengthening effect of the tooth tip improves the quenching hardness, but the high quenching temperature leads to martensitic coarser of the tooth back, which results in a significant decrease in the hardness. Moreover, with the increase in tempering temperature, the martensite in the microstructure of the tooth tip and tooth back was transformed into tempered trootensite and sortensite, and the primary and secondary carbides in the tooth tip became coarser, which led to the reduction of tempering hardness, and the fatigue properties changed too.

In this paper, the influence of induction quenching and tempering temperatures on the evolution of mechanical properties and microstructure of 45 steel for linear guides were investigated based on the tensile, impact, hardness tests and fracture morphology. The results indicate that the hardness of untempered and 200 °C tempered samples are higher and the difference is not significant, while the hardness of 300 and 400 °C tempered samples decrease as tempering temperature increases. Lower tensile strengths are observed in untempered and 200 °C tempered samples, which increase significantly after being tempered at 300 °C and then decrease slightly after being tempered at 400 °C. As the tempering temperature remains constant, the impact toughness value steadily declines as the quenching temperature rises, whereas when the quenching temperature remains constant, the impact toughness increases as the tempering temperature rises. The optimum induction quenching temperature was finally determined to be 850-900 °C, and the optimum tempering temperature was 300 °C. The findings of this study can be used to develop technical guidelines for the design of induction hardening and tempering process parameters for linear guides.