scholarly journals The interrelationships of magnetic and magneto acoustic-emission characteristics of heat-treated steels of various chemical composition

2018 ◽  
Vol 145 ◽  
pp. 05005 ◽  
Author(s):  
Vladimir Kostin ◽  
Evgeniy Serbin ◽  
Olga Vasilenko
Keyword(s):  
Chemical Composition ◽  
Magnetic Induction ◽  
Thermal Treatments ◽  
Field Frequency ◽  
Magnetoacoustic Emission ◽  
Amplitude Maximum ◽  
Heat Treated ◽  
Residual Magnetic Induction ◽  
Ferromagnetic Steels ◽  
Scanning Systems

The relationship between the amplitude of magnetoacoustic emission and the residual magnetic induction of the materials is shown. The dependence of magnetoacoustic emission (MAE) on the frequency of magnetization reversal of a group of steels of different chemical composition was investigated. In all the investigated cases, the MAE amplitude maximum corresponds to a field frequency of 3-5 Hz. The magnetic properties of two groups of steels subjected to various thermal treatments have been studied. It is shown that the residual magnetic induction of steels is a sufficiently universal parameter for controlling softening thermal treatments and that the amplitude of magnetoacoustic emission can be used as a testing parameter in scanning systems of structurescopy of ferromagnetic steels.

Thermomechanical Treatment of a 4340 Ni-Cr-Mo Alloy Steel

1981 ◽  
Vol 39 ◽  
pp. 314-315 ◽  
Author(s):  
M.T. Jahn ◽  
J.C. Yang ◽  
C.M. Wan
Keyword(s):  
Mechanical Property ◽  
Chemical Composition ◽  
Alloy Steel ◽  
Thermomechanical Treatment ◽  
Room Temperature ◽  
Good Combination ◽  
Thermal Treatments ◽  
Low Carbon ◽  
4340 Steel ◽  
Good Improvement

4340 Ni-Cr-Mo alloy steel is widely used due to its good combination of strength and toughness. The mechanical property of 4340 steel can be improved by various thermal treatments. The influence of thermomechanical treatment (TMT) has been studied in a low carbon Ni-Cr-Mo steel having chemical composition closed to 4340 steel. TMT of 4340 steel is rarely examined up to now. In this study we obtain good improvement on the mechanical property of 4340 steel by TMT. The mechanism is explained in terms of TEM microstructures4340 (0.39C-1.81Ni-0.93Cr-0.26Mo) steel was austenitized at 950°C for 30 minutes. The TMTed specimen (T) was obtained by forging the specimen continuously as the temperature of the specimen was decreasing from 950°C to 600°C followed by oil quenching to room temperature. The thickness reduction ratio by forging is 40%. The conventional specimen (C) was obtained by quenching the specimen directly into room temperature oil after austenitized at 950°C for 30 minutes. All quenched specimens (T and C) were then tempered at 450, 500, 550, 600 or 650°C for four hours respectively.

scholarly journals Selection of the chemical composition of steels and their thermal hardening mode using a computer program

2021 ◽  
pp. 59-65
Author(s):  
D. M. Berdiev ◽  
M. A. Uмаrоvа ◽  
A. A. Yusupov
Keyword(s):  
Wear Resistance ◽  
Chemical Composition ◽  
Computer Program ◽  
Sliding Friction ◽  
Thermal Hardening ◽  
Abrasive Particles ◽  
Density Of Dislocations ◽  
Heat Treated ◽  
Final Tempering ◽  
Selection Of

The relationships between the parameters of the structure of heat‑treated steels and their abrasive wear resistance are established. At all temperatures of the final tempering of hardened steel, there is a direct relationship between its structure parameters (the number of elements in a solid solution, the density of dislocations, the size of cementite particles and the intercementite distance) and wear resistance when sliding friction against loose abrasive particles. A computer program has been developed to select the chemical composition of the steel grade and methods of thermal hardening in order to ensure the required wear resistance.

Characterization of Local Deformation in Welded Joints Using a Combined Experimental and Numerical Approach

2014 ◽  
Vol 627 ◽  
pp. 241-244 ◽  
Author(s):  
Pawel Kucharczyk ◽  
Sebastian Münstermann
Keyword(s):  
Chemical Composition ◽  
Weld Metal ◽  
Welded Joints ◽  
Base Material ◽  
Welding Process ◽  
Numerical Approach ◽  
Geometrical Model ◽  
Local Deformation ◽  
Heat Treated ◽  
Welded Structure

The microstructure of welded joints differs significantly from that of the base material, what changes their mechanical properties and influences fatigue life. The aim of this work was the investigation of the local deformation field within a butt joint made of 10 mm thick structural steel S355. However, a direct sampling even of the weld metal was impossible due to small dimensions of butt joints. Therefore, the following procedure was utilized in order to manufacture big samples of the microstructure identical to that of the local weldment areas.A geometrical model of the welded structure describing the relevant areas e.g. weld metal, heat-affected zone was established. It was based on the results of the metallographic investigations, hardness mapping and electron-probe-micro-analysis of the local chemical composition. The welding process was numerically simulated using SYSWELD program to estimate the time-temperature-transition (TTT) curves for each identified area. The parameters of the heat input source were calibrated. Afterwards, the material of the defined chemical composition was heat-treated according to the TTT curves. For the validation purpose the heat-treated work pieces were evaluated in terms of microstructure and hardness distribution. Finally, the up-scaled samples of the respective bulk microstructure were manufactured and investigated in monotonic tests.

scholarly journals Calorific Power Improvement of Wood by Heat Treatment and Its Relation to Chemical Composition

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5322
Author(s):  
Idalina Domingos ◽  
Umit Ayata ◽  
José Ferreira ◽  
Luisa Cruz-Lopes ◽  
Ali Sen ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Chemical Composition ◽  
Lignin Content ◽  
Treated Wood ◽  
Untreated Wood ◽  
High Heating Value ◽  
Heat Treated ◽  
Positive Linear Correlation ◽  
Total Extractives ◽  
Calorific Power

Chemical composition influences the calorific power of wood, mainly due to the calorific power of structural compounds and extractives. Heat treatment changes the chemical composition of treated wood. This work studies the relationship between chemical composition and calorific power improvement by heat treatment. Samples were heat-treated by the ThermoWood process ® for 1 h and 2 h. High heating value (HHV) and chemical composition; lignin, cellulose, hemicelluloses and extractives in dichloromethane, ethanol, and water were determined. The HHV of untreated wood ranged between 18.54–19.92 MJ/kg and increased with heat treatment for all the tested species. A positive linear correlation was found between HHV and Klason lignin (R2 = 0.60). A negative trend was observed for holocellulose, cellulose, and hemicelluloses content against HHV, but with low determination coefficients for linear regression. The best adjust for polysaccharides was found for hemicelluloses content. A positive correlation could be found for dichloromethane extractives (R2 = 0.04). The same was obtained in relation to ethanol extractives with R2 = 0.20. For water and total extractives, no clear positive or negative trends could be achieved. The results showed that the HHV of wood increased with heat treatment and that this increase was mainly due to the increase in lignin content.

Near infrared spectroscopy to evaluate change in color and chemical composition in heat-treated bamboo

2020 ◽  
Vol 28 (4) ◽  
pp. 214-223
Author(s):  
Junqian Mo ◽  
Wenbo Zhang ◽  
Xiaohui Fu ◽  
Wei Lu
Keyword(s):  
Infrared Spectroscopy ◽  
Chemical Composition ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Prediction Models ◽  
Chemical Components ◽  
Outer Side ◽  
Heating Process ◽  
Least Squares Regression ◽  
Heat Treated

This study investigated the feasibility of using near infrared spectroscopy technology to predict color and chemical composition in the heat-treated bamboo processing industry. The quantitative presentations of the changes in the chemical components were discussed using the difference spectra method of the 2nd derivative NIR spectra of the heat-treated bamboo samples. Then, the relationships between the color changes of the heat-treated bamboo and its near infrared spectra were constructed using the changes in the chemical components of the bamboo samples during the heating process. The prediction of color and chemical composition of both the outer and inner sides of the heat-treated bamboo surface were constructed using partial least squares regression method combined with a leave-one-out cross-validation process. Then, the results were validated by independent sample sets. The proposed prediction models were found to produce high r2P (above 0.93), RPD (above 3.13), and low RMSEP for both the outer and inner sides of the heat-treated bamboo samples. These studies’ results confirmed that the proposed models, especially outer side models, were perfectly suitable for the in-process inspections of the color and chemical content changes of heat-treated bamboo.

Surface chemical composition analysis of heat-treated bamboo

2016 ◽  
Vol 371 ◽  
pp. 383-390 ◽  
Author(s):  
Fan-dan Meng ◽  
Yang-lun Yu ◽  
Ya-mei Zhang ◽  
Wen-ji Yu ◽  
Jian-min Gao
Keyword(s):  
Chemical Composition ◽  
Composition Analysis ◽  
Surface Chemical ◽  
Surface Chemical Composition ◽  
Heat Treated ◽  
Chemical Composition Analysis

Growth of Listeria spp. in Shredded Cabbage Is Enhanced by a Mild Heat Treatment

2010 ◽  
Vol 73 (3) ◽  
pp. 425-433 ◽  
Author(s):  
TIMOTHY C. ELLS ◽  
LISBETH TRUELSTRUP HANSEN
Keyword(s):  
Thermal Processing ◽  
Fruits And Vegetables ◽  
Storage Period ◽  
Thermal Treatments ◽  
Organoleptic Properties ◽  
Maximum Increase ◽  
Safety Issues ◽  
Heat Treated ◽  
Survival And Growth ◽  
Growth Inhibiting

Mild thermal processing can enhance the shelf life of cut fruits and vegetables by delaying the onset of spoilage and preserving the organoleptic properties of shredded cabbage. However, food safety issues related to this process have not been fully investigated. Therefore, the survival and growth of Listeria spp. on cabbage treated in this manner was examined. Experimentally, 24 strains of Listeria spp. (including L. monocytogenes) were inoculated onto cut and intact cabbage tissues and stored at 5°C. All strains on intact tissues exhibited a moderate decline in numbers (up to 1.0 log CFU/cm2) over the 28-day storage period. Conversely, cut tissue supported growth of most strains during the first 7 to 14 days of incubation with maximum increases of 1.2 log CFU/cm2. Subsequently, the survival or growth on heat-treated (50°C for 3 min) and untreated shredded cabbage of four L. monocytogenes and four nonpathogenic Listeria spp. strains were compared during storage for 21 days at 5°C. Growth on untreated shred for all strains was similar to the results observed on cut tissue with a maximum increase of approximately 1.0 log CFU/g. However, in the heat-treated cabbage shred all strains displayed a rapid increase in growth (up to 2.5 log CFU/g) during the first 7 days of incubation, which may be indicative of the destruction of an endogenous growth-inhibiting compound within the cabbage. In conclusion, this study shows that mild thermal treatments of cut cabbage may promote pathogen growth if other inimical barriers are not implemented downstream of the thermal treatment.

Study of Alpha-Beta Transformation in Ti-6Al-4V-ELI. Mechanical and Microstructural Characteristics

2010 ◽  
Vol 638-642 ◽  
pp. 712-717 ◽  
Author(s):  
Pascual Tarín ◽  
Aurelio Gualo ◽  
Atonio Garcia Simón ◽  
Nuria M. Piris ◽  
Jose Maria Badía
Keyword(s):  
Beta Phase ◽  
Alpha Phase ◽  
Thermal Treatments ◽  
Conductivity Measurements ◽  
Transformation Kinetics ◽  
Microstructural Characteristics ◽  
Annealed Condition ◽  
Heat Treated ◽  
Metallographic Observation ◽  
Alpha Beta

In the Ti-6Al-4V-ELI alloy, the alpha phase is gradually transformed into the beta phase until beta-transus temperature ( 980°C) is reached, and the transformation is completed. It is important to identify the transformation kinetics to accomplish the solution heat treatments in which a phase alpha percentage remains unchanged. Kinetics and other transformation characteristics are evaluated, as well as their influence on subsequent cooling transformations, by differential and dilatometric thermal analysis, electric conductivity measurements, hardness measurements and metallographic observation, after performing controlled thermal treatments. Starting from the mill annealed condition, samples were heated at temperatures between 650-1000 °C for 1 hour, then water quenched and subsequently heated for aging, air cooled. Finally, the mechanical properties of samples heat treated were obtained.

XPS Studies on Composite TiO2-SiO2 Thin Films Deposited on Metal Substrate by Sol-Gel

2005 ◽  
Vol 475-479 ◽  
pp. 1647-1650 ◽  
Author(s):  
Xin Gang Yu ◽  
Hong Wen Ma ◽  
Fei Long ◽  
Hui Feng Zhao ◽  
Wenrue Bi ◽  
...  
Keyword(s):  
Thin Films ◽  
Chemical Composition ◽  
Photoelectron Spectroscopy ◽  
Substrate Surface ◽  
Sol Gel ◽  
Stable State ◽  
Weight Percent ◽  
Metal Substrate ◽  
Metal Substrates ◽  
Heat Treated

Through X-ray photoelectron spectroscopy, by the aid of Ar+ sputtering, chemical composition and the valence state of elements on surface and at depth of TiO2-SiO2 thin films and metal substrates have been studied. Results show that: on surface, elements of Cr, Mn, Ti, Fe exist in the form of their respective stable state, but Si is unstable and exhibits stoichiometrical disturbance when heat treated at 800°C; at depth, after sputtering for 5 minutes and 17 minutes, elements of Cr, Mn, Ti and Ni exist in the form of their respective stable state, but Si and Fe are unstable and exhibit stoichiometrical disturbances; at depth, after sputtering for 57 minutes, all of the Cr, Mn, Ti, Si, Ni and Fe exist in the form of their respective stable state. Results of chemical composition and their content by weight percent of TiO2-SiO2 thin films and metal substrates reveal that: Fe, Cr, and Mn diffuse from metal substrates to the thin films in scale; Ni diffuses few and Si collects to the metal substrate surface

Instabilities in the Mechanical Stress in Deposited SiO2 Films Caused by Thermal Treatments

1990 ◽  
Vol 181 ◽  
Author(s):  
Bharat Bhushan ◽  
S.P. Murarka
Keyword(s):  
Heat Treatment ◽  
Mechanical Stress ◽  
Stress Measurement ◽  
In Situ Stress ◽  
Thermal Treatments ◽  
Heat Treated ◽  
Large Hysteresis ◽  
In Situ Stress Measurement ◽  
Deposited Films

ABSTRACTUsing an in-situ stress measurement technique that measures stress as a function of annealing temperature, instabilities in mechanical stress induced by heat treatment in a variety of doped/undoped SiO2 films deposited by APCVD, LPCVD and PECVD techniques have been investigated. A large hysteresis in mechanical stress, caused by first heat treatment to which the as-deposited films are subjected, has been observed in films deposited by APCVD/LPCVD techniques. No such hysteresis is obsesrved in films deposited by PECVD technique. Hysteresis in APCVD/LPCVD films is found to vanish once the films are heat treated at or above 800°C. The results are discussed in terms of oxide densification, the presence of hydrogenous species, and phosphorous.

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