Effect of Temperature and Cooling Rate on the Microstructures of 35MnB and 25Mn Tubes during Heat Treatment

2016 ◽  
Vol 866 ◽  
pp. 196-200
Author(s):  
Sun Ho Jung ◽  
S. Lee ◽  
J. Lee

Band structures with pearlite and ferrite aligned as stripes can be created during the heat treatment of carbon steel. Since band structures undermine the mechanical quality of end products, it is highly important to select a process condition that will not create band structures as a result of heat treatment. This study verified the effect of temperature and cooling rate on the creation of band structures during heat treatment of 35MnB and 25Mn steel tubes for drive shafts and also considered the optimal process conditions to remove band structures or prevent their creation. The experimental results suggest that, during heat treatment of 35MnB and 25Mn steel tubes, it is most effective to ensure a cooling rate faster than furnace cooling in order to prevent band structures.

Author(s):  
AW Hassan ◽  
MY Noordin ◽  
S Izman ◽  
K Denni

Heat treatment processes have a positive impact in improving the adhesion strength of different interlayer/substrate materials. However, information regarding the effect of these processes in enhancing the adhesion strength of an electroplated nickel interlayer on tungsten carbide substrate for diamond deposition is lacking. In this study, the effect of carburizing and annealing process conditions in enhancing the adhesion strength of the electroplated nickel interlayer was investigated. The heat treatment processes were designed and modeled by the design of experiments technique. The heat-treated specimens were characterized by the field-emission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction techniques. The adhesion of the interlayer before and after the heat treatment was assessed by the scratch test. The results show that the adhesion of the electroplated nickel interlayer was remarkably improved by both processes. The mathematical models for predicting the adhesion strength of the carburized and annealed nickel interlayer within the specified ranges were developed. The maximum adhesion strength of 30 N was obtained from the nickel interlayer annealed at the highest process condition of temperature and time.


2014 ◽  
Vol 31 (3) ◽  
pp. 193-200
Author(s):  
Dominik Jurków

Purpose – The paper aims to present the influence of the co-firing process conditions of low temperature co-fired ceramics (LTCC) on the deformation of thin LTCC membranes. Design/methodology/approach – The statistical design of the experiment methodology was used in the frame of these investigations to reduce the time and costs of the experiments and to ensure easier interpretation of the obtained results. Moreover, this conception permits the rough estimation of the membrane deflection fired at optimal process conditions. Findings – The applied design of the experiment methodology allowed the researchers to find the optimal co-firing process conditions and to estimate the membrane deflection at the optimal process conditions. The estimation fits well with the results of real measurement that was conducted to confirm the estimation precision. Research limitations/implications – The experiment was conducted for only one type of LTCC, DP951. The precision of the design of the experiment optimization and estimation of the response at optimal conditions depend on the described object. Therefore, the findings of this paper do not have to be generally true for other LTCC tapes, and if other LTCC tapes deformation should be investigated, then similar analysis shall be conducted for them. Practical implications – The deformation of LTCC membranes affects the sensitivity and repeatability of LTCC acceleration and pressure sensors. Hence, the decrease of membrane deflection increases the usability of LTCC in such applications. Originality/value – This paper presents simple optimization of co-firing process conditions of LTCC devices using statistical design of the experiment.


2011 ◽  
Vol 236-238 ◽  
pp. 2748-2752
Author(s):  
Shang Ling Fang ◽  
Yu Fang Yang ◽  
Da Zhen ◽  
Mao Bin Chen

In order to improve the quality of the black-skin-red-kojo, the Chinese rice wine yeast was introduced in the koji-making process,and adjusted the proportion of Monascusand Aspergillus niger and optimized the water content.Effects of different factors on the quality of the koji were investigated and the optimal process conditions were obtained through the orthogonal tests.


2008 ◽  
Vol 388 ◽  
pp. 213-216 ◽  
Author(s):  
Yumi Inagaki ◽  
Kenichi Kakimoto ◽  
Hitoshi Ohsato

Mn-doped Na0.5K0.5NbO3 (NKN) crystals have been grown by self-flux method under several heat-treatment conditions. The cooling rate affected the quality of Mn-doped NKN crystals significantly. When the cooling rate was 0.5 oC/min at temperatures ranging from 1050 to 950 oC, the synthesized Mn-doped NKN crystal exhibited a single nucleation growth, compared with multinucleation growth when the cooling rate was 0.25 oC/min at temperatures ranging from 1050 to 950 oC. The frequency dependence on the ferroelectric P-E hysteresis loop of the Mn-doped NKN crystal was not observed at measurement frequency of 0.1 – 25 Hz. The annealed 0.5 mol% Mn-doped NKN crystal exhibited excellent P-E hysteresis loop with Pr of 45.0 μC/cm2 and Ec of 7.2 kV/cm.


Energies ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 6177
Author(s):  
Rajib Mukherjee ◽  
Urmila M. Diwekar

Natural gas processing requires the removal of acidic gases and dehydration using absorption, mainly conducted in tri-ethylene glycol (TEG). The dehydration process is accompanied by the emission of volatile organic compounds, including BTEX. In our previous work, multi-objective optimization was undertaken to determine the optimal operating conditions in terms of the process parameters that can mitigate BTEX emission using data-driven metamodeling and metaheuristic optimization. Data obtained from a process simulation conducted using the ProMax® process simulator were used to develop a metamodel with machine learning techniques to reduce the computational time of the iterations in a robust process simulation. The metamodels were created using limited samples and some underlying phenomena must therefore be excluded. This introduces the so-called metamodeling uncertainty. Thus, the performance of the resulting optimized process variables may be compromised by the lack of adequately accounting for the uncertainty introduced by the metamodel. In the present work, the bias of the metamodel uncertainty was addressed for parameter optimization. An algorithmic framework was developed for parameter optimization, given these uncertainties. In this framework, metamodel uncertainties are quantified using real model data to generate distribution functions. We then use the novel Better Optimization of Nonlinear Uncertain Systems (BONUS) algorithm to solve the problem. BTEX mitigation is used as the objective of the optimization. Our algorithm allows the determination of the optimal process condition for BTEX emission mitigation from the TEG dehydration process under metamodel uncertainty. The BONUS algorithm determines optimal process conditions compared to those from the metaheuristic method, resulting in BTEX emission mitigation up to 405.25 ton/yr.


2012 ◽  
Vol 504-506 ◽  
pp. 487-492 ◽  
Author(s):  
Antonio Segatori ◽  
Barbara Reggiani ◽  
Lorenzo Donati ◽  
Tommaso Pinter ◽  
Y. Rami ◽  
...  

The increasing attention to magnesium alloys in extruded profiles, especially in the transportation industry, is related to their low density associated with good mechanical properties and complete recyclability. This allows to push towards both increasing efficiency and pollution restrictions. However, these advantages are negatively balanced by the production rates drop in relation to dangerous profile temperatures increasing that force to keep low velocities. In this context, a novel porthole die has been purposely designed for magnesium alloys allowing an increasing of the process velocity up to four times with respect to past solutions. The mandrel consisted of three ports made by 120° bridges that created an equal number of seam welds. The extruded tubes, made in ZM21, were 50 mm in diameter and 2 mm in thickness and were tested under different process conditions. In the present work, the quality of the seam welds has been investigated in relation to each process condition by means of the rubber plug testing method that allowed to applied an hydrostatic tensile state.


2007 ◽  
Vol 29-30 ◽  
pp. 83-86 ◽  
Author(s):  
Hyoung Wook Kim ◽  
Cha Yong Lim ◽  
Suk Bong Kang

Al-Mg alloy sheets with high Mg contents (3~10wt%Mg) were fabricated by twin roll strip casting. The optimum process conditions to get a good surface quality of Al-Mg strip have been suggested in this experiment. Controlling the cooling rate of cast roll was important to improve the surface quality of the strip and a compositional homogeneity through the thickness. The size of intermetallic particle like Al-Fe compound was reduced down to 1~2μm due to a high cooling rate of Al melt during strip casting. In addition, the dendrite structure was fine and the segregation of Al8Mg5 phase between grains was remarkably reduced. Therefore, the strips with a thickness of 3mm have good workability during additional hot/warm rolling processes. The hot/warm rolled Al-5wt%Mg sheets show high strength and elongation. When the rolled sheets were annealed at 300 oC for 1hr., the tensile strength and total elongation of the sheets reached at 290 MPa and 30%, respectively.


Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 586
Author(s):  
Eddy Plasquy ◽  
José María García Martos ◽  
María del Carmen Florido Fernández ◽  
Rafael Rubén Sola-Guirado ◽  
Juan Francisco García Martín

Harvesting at high temperatures and bulk transport can negatively influence the quality of olives and lead to undesirable alterations in the extracted oil. Cooling the fruit in the field would be the most logical solution, but it means that the olives arrive too cold at the mill for immediate processing. In this work, the use of warm water in the washing tub to warm up the fruit before grinding instead of flash heat treatment on the paste was assessed in two experiments. In the first one, at the laboratory level, the temperature after milling was determined in three olive cultivars, previously stored at 5 or 10 °C, and then submerged at different water temperatures (25, 30, and 35 °C) for 15, 30, 45, and 60 s. In the second one, two batches of olives were cooled in the field at 5 °C and then conditioned with washing water to obtain a paste at the entrance of the pilot plant malaxer at 27 °C. The temperature of the olives was measured at five points from the discharging up to their entering, as paste, into the malaxer. The results demonstrated the feasibility of the method as the temperature of the ground olives was kept at the desired temperature (28 ± 1 °C). The trials highlight the potential for automating an even more precise adjustment of the temperature of the olives before milling once the washing tub is equipped with a safe heating system.


Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1610
Author(s):  
Wiesław Przybylski ◽  
Danuta Jaworska ◽  
Katarzyna Kajak-Siemaszko ◽  
Piotr Sałek ◽  
Kacper Pakuła

An increase in the consumption of poultry meat has been observed due to its availability, nutritional value, and delicate flavor. These characteristics make it possible to prepare, with the use of spices and other additives, many different dishes and products for increasingly demanding consumers. The sous-vide technique is increasingly being used to give new sensory attributes to dishes in gastronomy. The study aimed to assess the impact of the heat treatment method, i.e., the sous-vide method, as compared to traditional cooking, on the sensory quality of poultry meat, as well as the efficiency of the process with regard to technological quality. The cooking yield with the sous-vide method of processing poultry meat was higher than with the traditional method of cooking in water (88.5% vs. 71.0%, respectively). The meat was also found to be redder (a* = 254 vs. 074) and less yellow (b* = 1512 vs. 1649), as well as more tender. The sensory quality of chicken breast meat obtained by the sous-vide method was higher in terms of attributes such as color tone, tenderness, juiciness, and overall quality. At the same time, it was lower in terms of the odor of cooked meat and the flavor of cooked meat as compared to meat subjected to traditional cooking.


2021 ◽  
Vol 9 (7) ◽  
pp. 1457
Author(s):  
Julia Hassa ◽  
Johanna Klang ◽  
Dirk Benndorf ◽  
Marcel Pohl ◽  
Benedikt Hülsemann ◽  
...  

There are almost 9500 biogas plants in Germany, which are predominantly operated with energy crops and residues from livestock husbandry over the last two decades. In the future, biogas plants must be enabled to use a much broader range of input materials in a flexible and demand-oriented manner. Hence, the microbial communities will be exposed to frequently varying process conditions, while an overall stable process must be ensured. To accompany this transition, there is the need to better understand how biogas microbiomes respond to management measures and how these responses affect the process efficiency. Therefore, 67 microbiomes originating from 49 agricultural, full-scale biogas plants were taxonomically investigated by 16S rRNA gene amplicon sequencing. These microbiomes were separated into three distinct clusters and one group of outliers, which are characterized by a specific distribution of 253 indicative taxa and their relative abundances. These indicative taxa seem to be adapted to specific process conditions which result from a different biogas plant operation. Based on these results, it seems to be possible to deduce/assess the general process condition of a biogas digester based solely on the microbiome structure, in particular on the distribution of specific indicative taxa, and without knowing the corresponding operational and chemical process parameters. Perspectively, this could allow the development of detection systems and advanced process models considering the microbial diversity.


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