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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.

AISI 431 martensitic stainless steels (MSS) with 2.5 wt% Cu were fabricated via laser-directed energy deposition additive manufacturing followed by single-step tempering treatment. The influences of different tempering times at 600 °C on microstructure and mechanical properties of the as-deposited 431-2.5Cu MSS have been explored and analyzed. The as-deposited MSS specimen primarily consisted of lath martensite, austenite and M23C6 carbide. After the single-step tempering treatment at 600 °C, Cu-enriched (ԑ-Cu) nano-precipitates and reverse austenite can be formed and promoted by extending the tempering treatment. The microhardness, strength and elongation can be improved with increasing the tempering time up to 1.0 h, and subsequently reduced with the tempering time prolonging to 2.0 h. Compared to 431 MSS that requires a multiple-step heat treatment for excellent performance, the 431-2.5Cu MSS specimen presented superior tensile properties after single-step tempering at 600 °C for 1.0 h in the present work. The ultimate tensile strength (UTS), yield strength (YS) and elongation (EL) of one-hour tempered MSS were 1611 MPa, 1334 MPa and 16.3%, respectively. This study provides a quantitative theoretical reference and experimental basis for realizing short-process fabrication of the Cu-bearing MSS with high strength and ductility.

Martensitic stainless steels (MSSs) have been widely used in the manufacture of turbine blades, surgical instruments, and cutting tools because of their hardness and corrosion resistance. The MSSs are usually tempered at a temperature no higher than 250 °C after quenching to avoid the decline in the hardness, strength, and corrosion resistance of the steels. However, some short-time thermal shocks are inevitable in processes like welding, water grinding, laser marking, etc., in the manufacturing of kitchen knives, all of which may have negative effects on the mechanical properties and corrosion resistance. The effects of these short-time thermal shocks have rarely been studied. In this paper, the martensitic stainless steel 5Cr15MoV (X50CrMoV15 is European Standards) was selected to be tempered at the sensitization temperatures (480 to 600 °C) for a series of times (0.5 to 128 min) after quenching, and the microstructures, hardness, and corrosion resistance of the steel after tempering were investigated. It was shown that the variation in hardness and corrosion resistance of the 5Cr15MoV steel could be divided into four stages over time during tempering at the sensitization temperatures. The hardness of steel was found to increase at first and then decrease with time; accordingly, good corrosion resistance was retained in the initial few minutes of tempering, which then deteriorated fast. The variation in hardness and corrosion resistance of the 5Cr15MoV steel is related to the diffusion of C and Cr atoms at different tempering temperatures. The mechanism of the mechanical properties and corrosion resistance variation caused by the diffusion of C and Cr atoms during tempering at the sensitization temperatures was also discussed.

Globally, up to 10% of the total annual rice production is wasted due to excessively high moisture content during storage. Mechanized drying of rice is an important measure to reduce this loss. However, traditional hot-air rice dryers have issues such as low drying rates and high energy consumption. This paper introduces a new type of gas-catalytic infrared rice dryer, including its working principle and components. By using drying rate and fissuring rate as evaluation indicators before and after drying, the performance of this dryer is compared with that of traditional hot-air dryers. Further, a three-factor, three-level orthogonal experimental method was employed. Batch processing capacity, conveyor belt speed, and tempering time were selected as variables to calculate the optimal operating conditions of the gas-catalytic infrared rice dryer using the comprehensive balance method. Experimental results show that under nine different operating conditions, the gas-catalytic infrared rice dryer outperforms the traditional hot-air dryer. The drying rate of the gas-catalytic infrared dryer increased by 215.15% compared to the traditional hot-air dryer, and the fissuring rate decreased by 86%. The orthogonal experimental results indicate that, based on a comprehensive evaluation of moisture content difference and fissuring rate, the gas-catalytic infrared dryer achieves the best drying effect when the conveyor belt speed is 1.92 m/min and the tempering time is 40 minutes. These research findings provide important references for further optimization of rice drying technology.

The hardness test, Charpy impact test, and axial expansion experiment were performed on a medium carbon steel S35C specimen typically used for shaft materials after first subjecting it to quenching and tempering heat treatment under different heating temperatures/time conditions. The effect of the tempering conditions on the mechanical properties of the specimen and the limit of the diameter-enlarged ratio used for evaluating the workability of the partial diameter-enlarged were investigated. The summary of the results are as follows: after quenching at 880 °C, a fine troostite or sorbite structure was obtained under all heat treatment conditions at heating temperatures of 550 °C to 675 °C, and heating times of 0.5 h to 1.5 h. An improvement was shown in the limit of the diameter-enlarged ratio because the quenching and tempering heat treatment led to an increase in the Charpy impact value/ductility as well as a reduction in the hardness, tensile strength, and yield strength; the partial diameter-enlarged process could be performed on the heat treated material at almost the same deformation speed as a cold-drawn material with a much lower axial pressure; it was possible to estimate the diameter-enlarged deformation behavior using the tempering parameter M. We confirmed that the quenching tempering heat treatment performed in this study facilitates the improvement of the workability of the diameter-enlarged.

The evolution of the microstructure, the precipitation behavior, and the mechanical performances of Nb-V-Ti micro-alloyed steel prepared under different tempering time were studied using transmission electron microscopy (TEM), X-ray diffraction (XRD), and mechanical tests. It was found that the width of the martensite laths increases with the increasing tempering time. Several kinds of carbides, including M3C, M2C, M23C6, M7C3, and MC particles, were identified after tempering. The MC carbides remain stable during tempering, but the transformation behavior of other carbides was identified. The transformation sequence can be summarized as: M3C → M2C → M7C3 → M23C6. The strength decreases and the Charpy impact toughness increases gradually with the increase in the tempering time. The ultimate strength (UTS) decreases from 1231 to 896 MPa, and the yield strength (YS) decreases from 1138 to 835 MPa. The −40 °C Charpy impact toughness increases from 20 to 61 J as the tempering time increases from 10 min to 100 h. The evolution of carbides plays an important role in their mechanical performances.

Yellow maize as raw materials, hot air drying was used to reduce moisture content, and the tempering was implemented after drying. This study aimed to investigate the effects of hot air drying temperature and tempering time on the properties of maize starch. The wet milling was used to extract maize starch. Starch yield, protein content, amylose and amylopectin content, transparency and coagulation, solubility index and swelling power, color, pasting properties, and gelatinization properties were researched. The results showed that when the hot air temperature increased, the properties such as starch yield, amylopectin content, transparency, solubility, swelling power, whiteness decreased, and properties such as protein content and amylose content, coagulation, gelatinization temperature increased. Compared to drying temperature, tempering time has a less remarkable effect on the maize starch properties. The maize starch with better whiteness, solubility, swelling power could be obtained by adjusting tempering time.

Present paper describes the microstructural and mechanical properties of creep strength enhanced Cr–Mo P91 steel subjected to a regime of tempering time 720–3000 h. Study on the effect of varying tempering time on microstructure revealed increase in size of precipitates, amount of precipitates and grain size. It was also observed that compared to particle size, effect of tempering time was more pronounced on the grain size. The various phases that formed in the tempered P91 steel were analyzed by X-ray diffraction. Yield strength and tensile strength were observed to be decreasing with increase in tempering time. Increase in duration of tempering time led to decrease in impact toughness of P91 specimens possibly due to cracking of secondary phase particles during straining and decohesion at precipitates and matrix interface. The tempering time also observed to be affecting the hardness of P91 steel but less pronounced compared to the yield strength and tensile strength. Tensile fracture and impact toughness fracture surfaces were studied by using scanning electron microscope. The fracture surface of tempered P91 tensile specimens indicated increased dimples and presence of fewer cleavage facets. The fracture surface of P91impact toughness specimens exhibited both inter lath-decohesion and ductile dimple tearing.

Ag-based low-E films with a multilayer construction of top-Si3N4/SnO2/NiCrOx/Ag/ZnO/ NiCrOx/TiO2/under-SiOxNy were deposited on unheated glass by vacuum magnetron sputtering and then post-treated in the glass tempering furnace at 675±25°C for 4 min, 5 min and 6 min, respectively. The effects of tempering time on the surface morphology, optical and micro-mechanical properties have been investigated. The results show that the edge of the particles become vague with the increasing time. After tempering, the transmittance of 550 nm is higher than that of the as-deposited glass of 75.89%. Ag-based Low-E films tempered at 675±25°C for 6 min possess the biggest value of the figure of merit of 6.86×10-3 Ω-1 and exhibits the optimal optoelectronic properties. The composite nanohardness increase from 8.04 GPa to 9.23 GPa and the elastic modulus increases from 62.39 GPa to 84.58 GPa when tempered from 0 min to 6 min.

The standard approach to Bayesian inference is based on the assumption that the distribution of the data belongs to the chosen model class. However, even a small violation of this assumption can have a large impact on the outcome of a Bayesian procedure. We introduce a novel approach to Bayesian inference that improves robustness to small departures from the model: rather than conditioning on the event that the observed data are generated by the model, one conditions on the event that the model generates data close to the observed data, in a distributional sense. When closeness is defined in terms of relative entropy, the resulting \"coarsened\" posterior can be approximated by simply tempering the likelihood-that is, by raising the likelihood to a fractional power-thus, inference can usually be implemented via standard algorithms, and one can even obtain analytical solutions when using conjugate priors. Some theoretical properties are derived, and we illustrate the approach with real and simulated data using mixture models and autoregressive models of unknown order. Supplementary materials for this article are available online.