Soaking Temperature Research Articles

The role of solvent soaking and pretreatment temperature in microwave-assisted pyrolysis of waste tea powder: Analysis of products, synergy, pyrolysis index, and reaction mechanism

This study focuses on microwave-assisted pyrolysis (MAP) of fresh waste tea powder and torrefied waste tea powder as feedstocks. Solvents including benzene, acetone, and ethanol were used for soaking feedstocks. The feedstock torrefaction temperature (at 150 °C) and solvents soaking enhanced the yields of char (44.2–59.8 wt%) and the oil (39.8–45.3 wt%) in MAP. Co-pyrolysis synergy induced an increase in the yield of gaseous products (4.7–20.1 wt%). The average heating rate varied in the range of 5–25 °C/min. The energy consumption in MAP of torrefied feedstock (1386 KJ) significantly decreased compared to fresh (3114 KJ). The pyrolysis index dramatically varied with the solvent soaking in the following order: ethanol (26.7) > benzene (25.6) > no solvent (10) > acetone (6). It shows that solvent soaking plays an important role in the pyrolysis process. The obtained bio-oil was composed of mono-aromatics, poly-aromatics, and oxygenated compounds.

The influence of different orientations and ventilation cases on temperature distribution of the car cabin in the hot soak

Thermal discomfort, fuel wastage, health risks, and the death threat of passengers/infants due to the hot soak of car cabin is a hot spot topic all the time. Therefore, the transient analysis method is used to study the distribution of the heat soak temperature in the passenger compartment under different orientation. Besides the research analyzed the effects of four ventilation cases on the driver and rear infant. The results show that both of the driver and infant are subjected to the lowest heat load while the vehicle parked outdoors is facing east at 14:00 and the air temperature around the driver is about 52 °C. The roof ventilation is a effective energy conservation ventilation way for both of driver and infant, as there is the most heat removal efficiency(0.471) and the best cooling effect. The head temperature of driver and infant in roof ventilation is at least 7 °C and 3 °C lower than the other three cases. In addition, the seats ventilation is a better heating way for driver than other ventilation cases, because the air temperature is more even and can be heated to 26.5–29.2 °C for the driver.

Influence of different homogenization heat treatments on the microstructure and hot flow stress of the aluminum alloy AA6082

Proper design of the homogenization heat treatment of 6000 series Al wrought alloys is crucial for processes such as hot rolling and extrusion. Important aspects are the precipitation and growth of dispersoids and the dissolution and re-precipitation of Mg-Si-precipitates. Studying these processes is laborious and experimentally demanding, limiting the feasibility of systematic study of variations in the homogenization regime. We conducted in situ differential scanning calorimetry (DSC) experiments of homogenization of AA6082 at different soak temperatures and cooling rates. The resultant heating and cooling curves were interpreted to obtain information on dispersoid number density and Mg-Si-phase dissolution and re-precipitation. Microstructural differences have been evaluated by scanning electron microscopy analysis. The results elucidate the complex relations between dissolution of primary Mg-Si-precipitates, dispersoid precipitation and growth, Mg-Si-re-precipitation, and hot forming behavior while reducing experimental effort compared to semi-industrial furnace trials. Overall, the homogenization soak temperature had the largest influence on these microstructural phenomena while differences due to the cooling rate were less pronounced in an industrially relevant range. In conclusion, in situ DSC can be used as a tool for rapid and inexpensive investigation of homogenization parameters • In-depth analysis of heating and cooling DSC curves. • Use of industry-relevant heating rates and homogenization soak temperatures/times. • Experimental effort is reduced compared to furnace trials. • Advanced SEM characterization of constituents, dispersoids, and Mg-Si-phases. • Microstructure after homogenization is discussed with regards to hot flow stress.

Aging and tribological behavior of styrene butadiene rubber conveyor belts under combined seawater dry-wet conditions

In this study, the aging and tribological behaviors of styrene butadiene rubber (SBR) conveyor belts exposed to seawater dry–wet cycles were investigated. Using hardness as a measure of the aging performance, the worst seawater dry-wet (W-SDW ) cycle conditions were selected using an orthogonal design method, the study was conducted based on such conditions. The changes in SBR surface properties and tribological properties with aging time before and after aging and the degree were investigated by using a hardness tester, SEM, EDS, etc. The performance degradation, microscopic morphological changes of wear surface, and evolutionary behavior of wear mechanism of styrene-butadiene rubber conveyor belt after aging by dry and wet cycles of seawater were discussed. The results show that the most severe combination of wet-dry cycles of seawater for the aging of SBR conveyor belts comprised a soak temperature of 45 °C, soak time of 12 h, drying temperature of 100 °C, and drying time of 9 h. The total surface discoloration of the conveyor belt increases as the number of W-SDW cycles increases, along with the hardness. The friction coefficient of the belt increases with increasing load and decreases with the increasing number of W-SDW cycles. The mass loss increases gradually with the number of W-SDW cycles and load. The wear mechanism gradually changes from fatigue wear to the damage mechanism of coexistence of adhesive wear and fatigue.

Optimization of soybean pre-treatment processes for the improvement of their nutritional, biochemical and bioactive characteristics

Soybeans (Glycine max) are one of the most widely grown oilseeds in the world. Soybeans are processed into several products. However, during these transformation processes, the nutritional value of the beans can be greatly affected. Therefore, it was important to find optimal conditions under which soybeans can be processed while retaining their nutritional value. The objective of the study was therefore to improve the nutritional composition of soybeans while optimizing the different processing techniques. Thus, untreated (EN), dehulled (ED), sprouted (EG), roasted (ETO,) and distilled water soaked (ET) soybeans were used to determine the proximate, bioactive and anti-nutritional composition. Sprouted (EG) and dehulled (ED) beans were subjected to temperature and time factors respectively to determine the action of these factors on the nutritional composition of soybeans. The results show that the different types of samples are rich in protein (37.98±2.75 g/100g DM), fat (20.02±1.87 g/100g DM), potassium (1838.68±2.75 mg/100g DM), and magnesium (276.45±8.47 g/100g). Sprouted seeds (ED) and hulled seeds (ED) showed the best nutritional potential. The effect of soaking temperature on shelled seeds and the monitoring of germination at 24h, 48h, and 72h allowed for optimizing the nutritional properties of soybeans. Thus, the samples germinated at 24 h showed the highest energy value while the seeds germinated at 72 h are more suitable in terms of functional foods and the hulled soybeans soaked at 40°C have a high food potential. These data are very important in food industries and for possible formulations.

Effect of soaking conditions in the reduction of antinutritional factors in sunnhemp (Crotalaria juncea) seeds

The study was conducted to optimize the effect of soaking conditions (soaking temperature and soaking time) on the antinutritional factors (total alkaloid content, total saponin content, total tannin content, total flavonoid content, total glycoside content and total steroids) present in sunnhemp seeds (Crotalaria juncea L.) using central composite rotatable design. The analysis revealed that independent variables (soaking temperature and soaking time) significantly affected all the dependent variables. The results indicated that with increased soaking temperature and soaking time, all antinutritional factors were reduced significantly. The maximum percentage reduction was 52.21, 36.34, 56.57, 35.54, 61.5 and 40.74% for alkaloids, saponins, tannins, flavonoids, glycosides and steroids, respectively. The optimum soaking conditions obtained was soaking temperature and time of 60 °C and 23.8 h, respectively. The obtained experimental values under optimized soaking conditions for total alkaloid content was 0.294 mg/g, total saponin content 65.91 mg/g, total tannin content 0.359 mg/g, total flavonoid content 3.127 mg/g, total glycoside content 0.067% and total steroids 0.156 mg/g, respectively. These results indicated that soaking can be an effective processing method for reduction of antinutritional factors from sunnhemp seeds to make it edible source of plant protein.

Effect of solutionizing temperature and cooling rate on phase morphology, recrystallization and texture evolution in a heat treated Ti‐6Al‐4Valloy having different types of microstructure

The effect of different solutionizing temperature and cooling rate on the extent of recovery, recrystallization and texture evolution in the alloy Ti‐6Al‐4V (Ti-64) has been investigated in different microstructural conditions. The hot rolled Ti-64 alloy was subjected to three different heat treatments in order to obtain three different microstructures, namely, lamellar (β-treatment), and equiaxed and bimodal (α/β-treatment). The heat treated alloys were characterized in terms of differences in phase fraction and phase dimension, the extent of recovery, recrystallization and texture evolution using SEM, EBSD, TEM, and XRD. The effect of heat treatment parameters on the volume fraction and grain size of primary α was more in bimodal microstructure than that of the equiaxed microstructure. The width of transformed α laths increases with increasing soaking temperature. Additionally, the extent of recovery and recrystallization of primary α was higher in equiaxed microstructure than in bimodal microstructure. The higher solutionizing temperature caused the dislocations in primary α to arrange themselves into lower energy substructures, which ultimately lead to subgrain formation. In transformed α laths, dislocations were generated due to lattice strain induced during β to α phase transformation. The rolling texture vanished gradually as the microstructure recovered and new recrystallized primary α grains grew. The newly formed recrystallized primary α grains and the majority of transformed α showed a moderate and strong prismatic texture respectively.

Study on pecan seed germination influenced by seed endocarp.

Nondeep physiological dormancy exists in freshly harvested pecan (Carya illinoinensis) seed, and the endocarp inhibits the seed germination. New methods were tried to detect if “chemical dormancy” or “mechanical dormancy” was caused by the endocarp. The germination of freshly harvested pecan seed with the removal of different parts of the endocarp and the fracture pressure of the endocarp of pecan seed soaked in water at different temperatures were tested. The results showed that (1) there was no significant difference in germination rate between the pecan kernel keeping in touch and out of touch with the same part of the endocarp, (2) whether a part of endocarp was removed to expose the radicle, preventing endocarp from splitting by glue inhibited the radicle elongation significantly, (3) the fracture pressure of the endocarp decreased significantly over water uptake time, and (4) little difference in the fracture pressure of the endocarp between different soaking temperatures. In conclusion, it suggested that (1) the endocarp caused “mechanical dormancy” but “chemical dormancy,” (2) the prevention of radicle elongation was due to the endocarp pressuring the cotyledon rather than the direct physical restriction on the radicle, and (3) the radicle elongation seemed to be able to respond to the suture split and the pressure on the cotyledon.

Microstructure, Mechanical and Wear Behaviour of Deep Cryogenically Treated EN 52 Silchrome Valve Steel.

This study has compared the performance of cryogenically processed EN 52 Silchrome valve steel with untreated material. After completing the standard heat treatment process, EN 52 steel material specimens are subjected to a deep cryogenic process with varying soaking temperatures. The parameters of the deep cryogenic procedure were changed to find the best wear qualities. The key features of valve steel, such as microstructure, mechanical, and wear behaviour are evaluated by conducting a test study. The evolution of wear mechanisms after enhancing qualities of EN 52 steel is studied using scanning electron microscopy. The mechanical and wear behaviour improved due to factors such as fine carbide precipitation, conversion of residual austenite, and carbide refining formed after cryogenic treatment. With a maximum reduction in wear rate of up to 45%, the deep cryogenic treatment of EN 52 steel with a soaking temperature of −140 °C was the ideal parameter. All three cryo-treated samples had better properties than the untreated EN 52 valve steel.

Effects of soaking temperature and ultrasonic power on the cooking time and physical properties of brown rice

The effect of ultrasonic soaking assisted microwave drying on the optimum cooking time and physicochemical properties of brown rice were investigated. After the ultrasonic soaking, the optimum cooking time of brown rice was significantly reduced, and the physical properties improved. The rice bran treated with high-temperature soaking and high-power ultrasound showed a porous structure with dense striped gaps. Accordingly, faster heat and mass transfer brought about the acceleration of drying rate and the reduction of drying time. The pretreatment and microwave drying reduced the gelatinization enthalpy (ΔH), which was beneficial to enhance the degree of gelatinization of starch. Microwave drying obviously increase the breakdown viscosity of brown rice flour, bringing about better tasting qualities. The content of free fatty acids, color parameters, and crystalline structure remained stable after pretreatment and microwave drying. Novelty impact statement Appropriate high-power ultrasound at the soaking temperature of 60°C assisted microwave drying significantly altered the structure of brown rice bran, reduced the optimum cooking time, and improved the physical properties of brown rice. Ultimately, our research proved that soaking and ultrasound-assisted microwave was a promising way to produce instant brown rice with high quality.

A study on the influences of a hygrothermal environment on the compressive strength and failure criteria of asphalt mixtures based on true triaxial tests

Based on a high-pressure servo static and dynamic true triaxial test machine (tawz-500/300), uniaxial and true triaxial tests of AC-25C asphalt mixtures under different heat moisture coupling treatments were performed, and the triaxial compressive strength value was determined by mathematical treatment. The test results show that in the range of 20–60 °C, the uniaxial and triaxial compressive strength of the AC-25C asphalt mixture decreases with increasing drying and soaking environment temperature. In the temperature range of 20–40 °C, the drying temperature sensitivity and soaking temperature sensitivity of the asphalt mixture with compressive strength and failure strain value as indices are the maximum. The increase in the intermediate principal stress can improve the triaxial compressive strength, and the increase reaches the maximum when the environmental treatment temperature is 40 °C. The maximum stress ratio is in the range of σ2/σ3 = 0.25 to σ2/σ3 = 0.5. The failure forms of uniaxial tension and triaxial tension are mainly caused by tensile stress. The influence of temperature, humidity and stress ratio on triaxial failure strength is analysed. The relationship between the failure strength and temperature coefficient k is established using a variety of failure criteria, which can provide an experimental and theoretical basis for the mechanical analysis of asphalt mixtures under complex stress states.

Factors Affecting Soybean Crude Urease Extraction and Biocementation via Enzyme-Induced Carbonate Precipitation (EICP) for Soil Improvement

Enzyme-induced carbonate precipitation (EICP) is a new biogeotechnical ground improvement technique that uses calcium carbonate (CaCO3) formed by biochemical processes to increase soil strength and stiffness. In this paper, crude urease extracted from soybeans was employed to catalyze the precipitation of CaCO3 in sand. To optimize the urease extraction efficiency, factors affecting the soybean crude urease extraction, including the powdered soybean particle size, concentration, soaking time, and soaking temperature, were addressed. This paper also provided further insight regarding the impact of the urease activity of soybean crude extract on the chemical conversion efficiency and the biocementation performance in EICP. The findings revealed that the powdered soybean concentration and the particle size were the two most important factors affecting the urease activity of the soybean crude extract. The enzyme activity utilized in the EICP process might further lead to different reactant efficiencies of urea-CaCl2 solution, and consequently, the improvement in the physical and mechanical properties of biocemented sand. Considering the chemical conversion efficiency and the biocementation performance, 60 g/L of powdered soybean was concluded as the preferred quantity for extracting the crude urease, with an enzyme activity of 6.62 mM urea min−1. Under this condition, a chemical conversion efficiency of approximately 95% for 0.5 M urea-0.5 M CaCl2 could be obtained in merely 12 h, and the unconfined compressive strength (UCS) of the EICP-treated sand exceeded 4 MPa with a CaCO3 content of ~8%. As a high-efficient cost-effective alternative to the purified enzyme for carbonate precipitation, the soybean crude urease showed great potential for ground improvement.

Ageing Susceptibility of Continuously Annealed Low-Carbon-Steel Strips

The continuously annealed low-carbon-steel strips from industrial production showed an average aging index of about 30 N/mm². This increase in yield strength caused by the continuous-annealing process was strongly dependent on the soaking temperature and the soaking time. Whilst the optimization of the overaging parameters and the use of a higher annealing temperature would reduce the ageing susceptibility of low-carbon-steel strips, it was considered unlikely that its magnitude could be reduced to a comparable level to that of the batch-annealed one. Within the limit of low-carbon-strip specifications, there was very little effect of the C content on the ageing. The aging index of the temper-rolled materials decreased with the increase in the temper-rolling reductions, and a maximum increase in yield strength was achieved at a temper-rolling reduction of about 1%. In this work, the effect of C content, Al content, continuous-annealing cycles, and temper-rolling reduction on the ageing susceptibility of the continuously annealed low-carbon-steel strips was examined. SEM/EBSD technique was developed to characterize the temper-rolling strain bands and to assess the effect of temper-rolling reduction on the yield strength of the low-carbon-steel strips.

Physical Treatment Reduces Trypsin Inhibitor Activity and Modifies Chemical Composition of Marama Bean (Tylosema esculentum).

The utility of the marama bean (MB) as an alternative protein source to soybean (SB) can be limited by the high concentration of trypsin inhibitors (TI). The physical treatment of MB has the potential to ameliorate the antinutritional activities of TI and modify other chemical components. Thus, this study investigated the effects of physical treatments on the chemical components and trypsin inhibitor activity (TIA) of raw MB and SB. The bean substrates were subjected to each of the following treatment methods: (1) room temperature (20–22 °C) soaking for 24 h; (2) electric stove cooking at 100 °C for 10, 20, and 30 min; (3) steam autoclaving at a temperature of 110 °C and pressure of 7 pounds per square inch (psi), as well as a temperature of 121 °C and 7 psi for 5, 15, and 30 min; (4) pre-soaked autoclaving at 110 °C (7 psi) and 121 °C (17 psi) for 5, 15, and 30 min. Treated MB and SB had greater (p < 0.05) crude protein content than untreated samples. All the treatments (except 24 h soaking of MB) reduced (p < 0.05) the TIA and ash content. Marama and SB are similar in protein content, but their amino acids profile and TIA are quite different. Soaking for 24 h was less effective in reducing TIA in MB and SB, compared to the thermal methods, and it was detrimental to the ash and amino acids profile of the two beans. Soaking prior to autoclaving yielded beans with the lowest TI concentrations. In conclusion, thermal methods reduced the TI contents and modified the level of proximate components and amino acids profile of the beans.

Post-fire stress-strain response of structural ferritic stainless steels

In this study, the effects of heating temperature and heat soak time on the post-fire stress-strain behaviour of three ferritic stainless steel grades (i.e., EN 1.4003, 1.4016, 1.4509) are experimentally investigated. The test results revealed that the three grades behaved very differently after exposure to elevated temperatures because of microstructure changes during heating and cooling down to room temperature. The heating temperature affected not only the residual strength and deformation capacity but also the shape of the stress-strain curve. A prolonged heat soak had no noticeable effect on the steel grade 1.4509 but increased strength loss of grades 1.4003 and 1.4016. Two stress-strain models, i.e., one exhibiting continuous yielding (without yield plateau) and the other with yield plateau, were proposed to use jointly to capture the post-fire stress-strain response of the three ferritic grades.

Physicochemical Properties and Hydration Kinetics of Kenaf (Hibiscus cannabinus) Seed

Hydration of kenaf seed was studied at 25, 35 45, 55 and 65 °C by the method of weight gain until equilibrium was achieved along with the physicochemical properties of the seed. The results showed that the kenaf seed had a small dimension and brownish surface color. Water absorbed during soaking was a function of soaking time and temperature. Soaking at higher temperatures increased the hydration rate constant and decreased the soaking time needed to reach equilibrium. Sigmoidal, Peleg and Page models effectively described the hydration characteristics of the seed under the soaking temperatures. The half-saturation time; τ, Peleg' s rate constant; K1 and Page rate constant K3 decreased from 199.78-32.97 min, 2.55-0.47 min/% and 3.14-2.74 min/%, respectively, while the sigmoidal rate constant; K increased from 0.85-6.83 min-1 with an increase in soaking temperature from 25-65 °C. The rate of water absorption of the seed at a higher temperature was faster. The temperature dependence of K was explained by the Arrhenius equation, from which activation energy of 71.31 KJ/mol was obtained.

Optimization of Vacuum Brazing Process Parameters in Ti-6Al-4V Alloy

In this study, the optimal parameters of the vacuum brazing titanium alloy Ti-6Al-4V with TiCuNi filler (30 μm-thick metal foil) were investigated by the Taguchi method. The microstructures, microhardness, and fractographs of the titanium brazed joints produced by these optimal parameters were also analyzed. The results of this study demonstrate that for the best tensile strength, the optimal combination of process parameters is: 890 °C soaking temperature, 60 min soaking time, 975 °C brazing temperature, and 45 min brazing time. The tensile strength obtained by welding with the optimal parameters was found to be 1265 MPa. A small error of 0.24% between experimental and predicted values confirmed the validity of the combined optimized parameters. Finally, from the means of variance analysis (ANOVA), out of the four factors, the highest contribution to the optimal parameters was found to be the brazing time, accounting for 47.3%. The base material of vacuum brazing (VB) weldment is mainly composed of white granular α titanium, slender β titanium, and layered structures that are interlaced by α and β. The weld bead, composed of Ti-15Cu-15Ni, contains many slender needle-shaped Widmanstätten structures. This structure is associated with higher strength and lower ductility. The weld bead hardness of the vacuum brazed parts is higher than that of laser beam weldment and gas tungsten arc weldment. This study demonstrates the feasibility of the Taguchi method for obtaining the optimal process parameters of titanium vacuum brazed joints.

Viability and vigor of Moringa oleifera Lam. seeds using the tetrazolium test

To evaluate the physiological potential of the seeds, the tetrazolium test would be an interesting alternative, as it is a quick test that provides a detailed analysis of viability and vigor. Therefore, it is necessary to define pre-conditioning conditions, such as temperature and duration of soaking, concentration of the tetrazolium solution, and method of exposing the seeds to staining. Moringa oleifera Lam., belonging to the family Moringaceae, is widely distributed in tropical countries and easily adapted to semi-arid conditions, possessing medicinal value, as forage, condiment, in the cosmetics industry, melliferous, fuel, and in water purification treatment through the coagulant solution made from seeds. Based on the above, the objectives of the present work were to establish the most appropriate procedure for conducting the tetrazolium test to evaluate the viability and vigor of M. oleifera seeds. Only the cotyledons containing the embryo were placed in 50 mL plastic cups and immersed in a solution of 2,3,5-triphenyl chloride tetrazolium salt at concentrations of 0.05; 0.075 and 0.1% for staining periods of 1, 2, and 3 hours in a Biochemical Oxygen Demand chamber at 30 ºC in the dark. The seeds were evaluated one by one for tissue condition (firm or flaccid) and seed color, and by the location and size of the lesions on the cotyledon and embryonic axis. For the standardization of the tetrazolium test, the Completely Randomized Design was used in a 3x3+1 factorial scheme (three concentrations of tetrazolium solution x three staining periods + control = germination test) with four repetitions of 25 seeds. M. oleifera seeds were found to have a high germination rate (100%), there was no significant difference between the control and the percentage of viable seeds (TZ) for the 2 and 3 hours staining periods, immersed in tetrazolium solution at concentrations of 0.075 (96%) and 0.05% (99%), respectively. The most appropriate procedure for conducting the tetrazolium test to assess the viability and vigor of M. oleifera seeds is to use a concentration of 0.05% for 3 hours of salt immersion

Hydration resistance and mechano-physical properties improvement of a magnesia-dolomite dense refractory by hercynite spinel

Year by year, the total demand for cement production has been growing. To be more competitive, cement producers have implemented new operating practices based on new eco–friendly raw materials. Lately, magnesia-dolomite refractories have been considered chrome-free refractories that might substitute magnesia–spinel and magnesia–chromite lining bricks for the cement industry with benefits to human health and the environment. However, their use is limited due to their low hydration resistance. In the present work, the hercynite's effect on the magnesia-dolomite properties (crystallographic, microstructural, physical, and mechanical) was studied. Refractory specimens were formed by uniaxial pressure, followed by a drying and fyring process, reaching a soaking temperature of 1600 °C. According to the XRD and SEM analysis, hercynite promotes hydration resistance and mechanical strengthening in the refractory body. These improvements are mainly due to brownmillerite formation. Brownmillerite diffuses through the grain boundary and triple points, forming a necklace-like microstructure (solidified liquid network) surrounding the magnesia and free-lime particles. Furthermore, it was observed that this structure avoids the progress of the expansive hydration process in the portlandite particles. Hercynite-containing refractory specimens exhibit superior physical and mechanical properties than conventional magnesia-dolomite refractories. By hercynite addition, an improvement of ∼35% in mechanical strength and ∼50% in hardness was found.

Process parameter analysis of deep cryogenic treated EN 52 Silicon chromium valve steel through Taguchi technique

ABSTRACT This paper analyses the performance of the cryogenically treated En 52 valve steel. This steel is processed with cryogenic treatment by varying parameters. The factors selected for the analysis are soaking period, temperatures of soaking and tempering. The trials derived from design of experiments L9 (33) orthogonal array with Taguchi technique were executed. The mechanical properties are measured for the cryogenic-treated En 52 material as per standard method. The tensile strength and hardness of the treated cryogenic En 52 steel have been selected as the responses. Combination of optimum parameters for cryogenic treatment was achieved from response parameters of Taguchi approach. The analysis of variance was used to recognize the most effective determinant for cryogenic process of En 52 steel. Soaking period was found to be the most influencing factor for both tensile strength and hardness outputs. Soaking temperature was the second-best parameter followed by tempering temperature.