Features of phase transformations in powder steels upon heating

Abstract At present, powder materials are used in practically all branches of industry, from medicine to aerospace technology. This is a wide range of materials ranging from constructional and instrumental materials and ending with special-purpose materials and medical implants. Powder metallurgy methods are most often used where the manufacture of products with desired properties is impossible using traditional methods: casting, stamping, etc. Heat treatment is understood as a set of operations of heating, holding at high temperatures and cooling in order to change the structure and workability of the material, improve the combination of its mechanical and physical properties without changing the shape and size of products. Heat treatment is an effective method for improving the physical and mechanical properties and wear resistance of steel. The specific features of sintered steels (porosity, structural heterogeneity, high oxidizability, etc.) make it difficult to use the technological modes of heat treatment developed for cast steels, although the main regularities of the processes occurring during heating and cooling of compact steel can be transferred to sintered materials. Heat treatment of powder steels has a number of features, primarily due to residual porosity, as well as chemical and structural heterogeneity.

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Influence of alloying components on diffusion and bonding processes in powder materials

Journal of Physics Conference Series ◽

10.1088/1742-6596/2131/4/042024 ◽

2021 ◽

Vol 2131 (4) ◽

pp. 042024

Author(s):

M Egorov ◽

R Egorova ◽

A Atrohov ◽

V Ekilik

Keyword(s):

Powder Metallurgy ◽

Rapid Development ◽

Alloying Elements ◽

Powder Materials ◽

Iron Powders ◽

Cast Steels ◽

Wide Range ◽

Aerospace Technology ◽

Alloy Steels ◽

Characteristic Features

Abstract At present, powder materials are used in practically all branches of industry, from medicine to aerospace technology. This is a wide range of materials ranging from constructional and instrumental materials and ending with special-purpose materials and medical implants. Powder metallurgy methods are most often used where the manufacture of products with desired properties is impossible using traditional methods: casting, stamping, etc. The production of all these materials is based on such basic operations as: obtaining starting materials, molding from these materials blanks of a given shape, size and strength, and sintering, intended for the final formation of the required properties and dimensions. The peculiarity of powder metallurgy technology allows creating a huge variety of developed technological schemes, which puts these technologies to a new level and allows for the rapid development of many industries. Alloying powder steels, in contrast to cast steels, has a number of characteristic features due to the specificity of their production. The structure of powder alloy steels and their properties depend on the methods of obtaining steels and technological features of their production. The following main methods of obtaining powder alloyed steels can be named: preparation of multicomponent mixtures of powders of iron and alloying elements and their subsequent processing; the use of alloyed iron powders, to which, if necessary, add carbon or other alloying elements; impregnation with liquid alloying metals or diffusion saturation of frameworks sintered from iron powders.

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Heat Treatment of Steel 1.1730 with Concentrated Solar Energy

Materiale Plastice ◽

10.37358/mp.19.1.5163 ◽

2019 ◽

Vol 56 (1) ◽

pp. 261-270

Author(s):

Maria Stoicanescu ◽

Aurel Crisan ◽

Ioan Milosan ◽

Mihai Alin Pop ◽

Jose Rodriguez Garcia ◽

...

Keyword(s):

Heat Treatment ◽

Solar Radiation ◽

Solar Energy ◽

Vertical Axis ◽

Solar Furnace ◽

Solid Base ◽

Heating And Cooling ◽

Concentrated Solar Energy ◽

Wide Range ◽

The Impact

This paper presents and discusses research conducted with the purpose of developing the use of solar energy in the heat treatment of steels. For this, a vertical axis solar furnace called at Plataforma Solar de Almeria was adapted such as to allow control of the heating and cooling processes of samples made from 1.1730 steel. Thus temperature variation in pre-set points of the heated samples could be monitored in correlation with the working parameters: the level of solar radiation and implicitly the energy used the conditions of sample exposed to solar radiation, and the various protections and cooling mediums.The recorded data allowed establishing the types of treatments applied for certain working conditions. The distribution of hardness, as the representative feature resulting from heat treatment, was analysed on all sides of the treated samples. In correlation with the time-temperature-transformation diagram of 1.1730 steel, the measured values confirmed the possibility of using solar energy in all types of heat treatment applied to this steel. In parallel the efficiency of using solar energy was analysed in comparison to the energy obtained by burning methane gas for the heat treatment for the same set of samples. The analysis considered energy consumption, productivity and the impact on the environment. Thanks to various data obtained through developed experiences, which cover a wide range of thermic treatments applied steels 1.1730 model, we can certainly state that this can be a solid base in using solar energy in applications of thermic treatment at a high industrial level.

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Isolation of fine powder faction obtained by electroerosion dispersion method

Tekhnicheskiy servis mashin ◽

10.22314/2618-8287-2020-58-3-119-127 ◽

2020 ◽

pp. 119-127

Author(s):

Il’ya V. Romanov ◽

Roman N. Zadorozhniy

Keyword(s):

Fine Particles ◽

Fine Fraction ◽

Fine Powder ◽

Physical And Mechanical Properties ◽

Ceramic Filter ◽

Research Purpose ◽

Powder Materials ◽

Metal Powders ◽

Large Spread ◽

Wide Range

The fundamental properties of metal powders with small particles change, which opens up a wide range of applications of such materials. Currently, nanopowders are used in many industries to improve the quality of the resulting products. (Research purpose) The research purpose is in isolating a fine fraction of metal powders obtained by electroerosive dispersion for further experiments with this material, and also proving the possibility of obtaining such fractions by this method. (Materials and methods) A fine fraction of metal powders obtained by the method of electroerosive dispersion was isolated, which proved its effectiveness in obtaining conductive powder materials with the desired final physical and mechanical properties. This method results in a fairly large spread across fractions. Authors received material for research on experimental installations of the "Nano-Center" Center for Collective Use. The article presents the methods of experimental research of fractional composition on the example of metal powders of hard alloy grades T15K6 and VK8, copper powder M1, brass powder LTs38MTsS2 and bronze powder BrAZh9-12 obtained by electroerosive dispersion. (Results and discussion) The metal powder was divided into three fractions, depending on the particle size: more than 0.071 mm, from 0.02 to 0.071 mm and less than 0.02 mm. The presence of fine particles of less than 1.5 microns in the total mass of the studied powders was proved using a membrane method with a ceramic filter. Sedimentation showed specific sizes of minimal particles (from 86.4 to 116 nm). (Conclusions) Based on the results of experiments, it is possible to obtain metal powders of a fine fraction using the method of electroerosive dispersion.

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Effect of Heat Treatment Parameters on Mechanical Properties of Medium Carbon Steel

Mechanics and Mechanical Engineering ◽

10.2478/mme-2018-0071 ◽

2020 ◽

Vol 22 (4) ◽

pp. 909-918 ◽

Cited By ~ 1

Author(s):

M. M. Blaoui ◽

M. Zemri ◽

A. Brahami

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Cooling Rate ◽

Heating Rate ◽

Physical And Mechanical Properties ◽

Medium Carbon Steel ◽

Holding Time ◽

Austenitization Temperature ◽

Heating And Cooling ◽

Heat Treated

AbstractEngineering materials, mostly steel, are heat treated under controlled sequence of heating and cooling to alter their physical and mechanical properties to meet desired engineering applications. This paper presents a study of the influence of austenitization temperature, cooling rate, holding time and heating rate during the heat treatment on microstructure and mechanical properties (tensile strength, yield strength, elongation and hardness) of the C45 steel. Specimens undergoing different heat treatment lead to various mechanical properties which were determined using standard methods. Microstructural evolution was investigated by scanning electron microscopy (SEM). The results revealed that microstructure and hardenability of the C45 steel depends on cooling rate, austenitization temperature, holding time and heating rate.

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Thermal properties of cement mortar with different mix proportions

Materiales de Construcción ◽

10.3989/mc.2020.09219 ◽

2020 ◽

Vol 70 (339) ◽

pp. 224 ◽

Cited By ~ 1

Author(s):

P. Shafigh ◽

I. Asadi ◽

A. R. Akhiani ◽

N. B. Mahyuddin ◽

M. Hashemi

Keyword(s):

Thermal Conductivity ◽

Compressive Strength ◽

Thermal Properties ◽

Thermal Diffusivity ◽

Cement Mortar ◽

Construction Material ◽

Physical And Mechanical Properties ◽

Sem Images ◽

Heating And Cooling ◽

Wide Range

The energy required for the heating and cooling of buildings is strongly dependant on the thermal properties of the construction material. Cement mortar is a common construction material that is widely used in buildings. The main aim of this study is to assess the thermal properties of cement mortar in terms of its thermal conductivity, heat capacity and thermal diffusivity in a wide range of grades (cement: sand ratio between 1:2 and 1:8). As there is insufficient information to predict the thermal conductivity and diffusivity of a cement mortar from its physical and mechanical properties, the relationships between thermal conductivity and diffusivity and density, compressive strength, water absorption and porosity are also discussed. Our results indicate that, for a cement mortar with a 28-day compressive strength in the range of 6–60 MPa, thermal conductivity, specific heat and thermal diffusivity are in the range of 1.5–2.7 W/(m.K), 0.87–1.04 kJ/kg.K and 0.89–1.26 (x10-6 m2/s), respectively. The scanning electron microscope (SEM) images showed that pore size varied from 18 μm to 946 μm for samples with different cement-to-sand ratios. The porosity of cement mortar has a significant effect on its thermal and physical properties. For this reason, thermal conductivity and thermal diffusivity was greater in cement mortar samples with a higher density and compressive strength.

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INFLUENCE THE QUENCHING AND TEMPERING ON THE MICROSTRUCTURE, MECHANICAL PROPERTIES AND SURFACE ROUGHNESS, OF MEDIUM CARBON STEEL

THE IRAQI JOURNAL FOR MECHANICAL AND MATERIALS ENGINEERING ◽

10.32852/iqjfmme.vol18.iss1.78 ◽

2018 ◽

Vol 18 (1) ◽

pp. 125-135

Author(s):

Sattar H A Alfatlawi

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Surface Roughness ◽

Carbon Steel ◽

Cold Water ◽

Medium Carbon Steel ◽

Medium Carbon ◽

Heating And Cooling ◽

Treatment Processes ◽

Quenching And Tempering

One of ways to improve properties of materials without changing the product shape toobtain the desired engineering applications is heating and cooling under effect of controlledsequence of heat treatment. The main aim of this study was to investigate the effect ofheating and cooling on the surface roughness, microstructure and some selected propertiessuch as the hardness and impact strength of Medium Carbon Steel which treated at differenttypes of heat treatment processes. Heat treatment achieved in this work was respectively,heating, quenching and tempering. The specimens were heated to 850°C and left for 45minutes inside the furnace as a holding time at that temperature, then quenching process wasperformed in four types of quenching media (still air, cold water (2°C), oil and polymersolution), respectively. Thereafter, the samples were tempered at 200°C, 400°C, and 600°Cwith one hour as a soaking time for each temperature, then were all cooled by still air. Whenthe heat treatment process was completed, the surface roughness, hardness, impact strengthand microstructure tests were performed. The results showed a change and clearimprovement of surface roughness, mechanical properties and microstructure afterquenching was achieved, as well as the change that took place due to the increasingtoughness and ductility by reducing of brittleness of samples.

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Structure and properties of compact articles from high-alloyed iron powder with adding of boron nitride

Perspektivnye Materialy ◽

10.30791/1028-978x-2020-8-39-48 ◽

2020 ◽

pp. 39-48

Author(s):

B. O. Bolshakov ◽

◽

R. F. Galiakbarov ◽

A. M. Smyslov ◽

◽

...

Keyword(s):

Mechanical Properties ◽

Boron Nitride ◽

Grain Boundary ◽

Bending Strength ◽

Physical And Mechanical Properties ◽

Operating Conditions ◽

Structure And Properties ◽

Steam Turbines ◽

Friction Forces ◽

Wide Range

The results of the research of structure and properties of a composite compact from 13 Cr – 2 Мо and BN powders depending on the concentration of boron nitride are provided. It is shown that adding boron nitride in an amount of more than 2% by weight of the charge mixture leads to the formation of extended grain boundary porosity and finely dispersed BN layers in the structure, which provides a high level of wearing properties of the material. The effect of boron nitride concentration on physical and mechanical properties is determined. It was found that the introduction of a small amount of BN (up to 2 % by weight) into the compacts leads to an increase in plasticity, bending strength, and toughness by reducing the friction forces between the metal powder particles during pressing and a more complete grain boundary diffusion process during sintering. The formation of a regulated structure-phase composition of powder compacts of 13 Cr – 2 Mо – BN when the content of boron nitride changes in them allows us to provide the specified physical and mechanical properties in a wide range. The obtained results of studies of the physical and mechanical characteristics of the developed material allow us to reasonably choose the necessary composition of the powder compact for sealing structures of the flow part of steam turbines, depending on their operating conditions.

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Damage Evolution of Granodiorite after Heating and Cooling Treatments

Minerals ◽

10.3390/min11070779 ◽

2021 ◽

Vol 11 (7) ◽

pp. 779

Author(s):

Mohamed Gomah ◽

Guichen Li ◽

Salah Bader ◽

Mohamed Elkarmoty ◽

Mohamed Ismael

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Failure Mode ◽

Physical And Mechanical Properties ◽

P Wave ◽

Physical Parameters ◽

Slow Cooling ◽

Heating And Cooling ◽

Natural Rock ◽

The Impact

The awareness of the impact of high temperatures on rock properties is essential to the design of deep geotechnical applications. The purpose of this research is to assess the influence of heating and cooling treatments on the physical and mechanical properties of Egyptian granodiorite as a degrading factor. The samples were heated to various temperatures (200, 400, 600, and 800 °C) and then cooled at different rates, either slowly cooled in the oven and air or quickly cooled in water. The porosity, water absorption, P-wave velocity, tensile strength, failure mode, and associated microstructural alterations due to thermal effect have been studied. The study revealed that the granodiorite has a slight drop in tensile strength, up to 400 °C, for slow cooling routes and that most of the physical attributes are comparable to natural rock. Despite this, granodiorite thermal deterioration is substantially higher for quick cooling than for slow cooling. Between 400:600 °C is ‘the transitional stage’, where the physical and mechanical characteristics degraded exponentially for all cooling pathways. Independent of the cooling method, the granodiorite showed a ductile failure mode associated with reduced peak tensile strengths. Additionally, the microstructure altered from predominantly intergranular cracking to more trans-granular cracking at 600 °C. The integrity of the granodiorite structure was compromised at 800 °C, the physical parameters deteriorated, and the rock tensile strength was negligible. In this research, the temperatures of 400, 600, and 800 °C were remarked to be typical of three divergent phases of granodiorite mechanical and physical properties evolution. Furthermore, 400 °C could be considered as the threshold limit for Egyptian granodiorite physical and mechanical properties for typical thermal underground applications.

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An Insight into Saponins from Quinoa (Chenopodium quinoa Willd): A Review

Molecules ◽

10.3390/molecules25051059 ◽

2020 ◽

Vol 25 (5) ◽

pp. 1059 ◽

Cited By ~ 7

Author(s):

Khadija El Hazzam ◽

Jawhar Hafsa ◽

Mansour Sobeh ◽

Manal Mhada ◽

Moha Taourirte ◽

...

Keyword(s):

Heat Treatment ◽

Bitter Taste ◽

Biological Activities ◽

Chenopodium Quinoa ◽

Toxic Effects ◽

Mechanical Abrasion ◽

Important Group ◽

The Past ◽

Wide Range ◽

Insight Into

Saponins are an important group found in Chenopodium quinoa. They represent an obstacle for the use of quinoa as food for humans and animal feeds because of their bitter taste and toxic effects, which necessitates their elimination. Several saponins elimination methods have been examined to leach the saponins from the quinoa seeds; the wet technique remains the most used at both laboratory and industrial levels. Dry methods (heat treatment, extrusion, roasting, or mechanical abrasion) and genetic methods have also been evaluated. The extraction of quinoa saponins can be carried out by several methods; conventional technologies such as maceration and Soxhlet are the most utilized methods. However, recent research has focused on technologies to improve the efficiency of extraction. At least 40 saponin structures from quinoa have been isolated in the past 30 years, the derived molecular entities essentially being phytolaccagenic, oleanolic and serjanic acids, hederagenin, 3β,23,30 trihydroxy olean-12-en-28-oic acid, 3β-hydroxy-27-oxo-olean-12en-28-oic acid, and 3β,23,30 trihydroxy olean-12-en-28-oic acid. These metabolites exhibit a wide range of biological activities, such as molluscicidal, antifungal, anti-inflammatory, hemolytic, and cytotoxic properties.

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Polyhedral Oligomeric Silsesquioxane (POSS)-Modified Thermoplastic and Thermosetting Nanocomposites: A Review

Polymers and Polymer Composites ◽

10.1177/096739110801600802 ◽

2008 ◽

Vol 16 (8) ◽

pp. 483-500 ◽

Cited By ~ 14

Author(s):

Jianqing Zhao ◽

Yi Fu ◽

Shumei Liu

Keyword(s):

Processing Condition ◽

Polyhedral Oligomeric Silsesquioxane ◽

Physical And Mechanical Properties ◽

Molecular Geometry ◽

Surface Hydrophobicity ◽

Dielectric Constants ◽

Great Promise ◽

Wide Range ◽

Oligomeric Silsesquioxane ◽

Mechanical Strengths

Polyhedral oligomeric silsesquioxane (POSS) nanoparticles have been successfully incorporated into thermoplastic and thermoset polymers via copolymerization, grafting, blending, surface bonding, or other transformations. A great promise in the development of a wide range of POSS-containing nanocomposites with diversely improved properties has been displayed. Thermal properties, viscoelastic properties, mechanical strengths, dielectric constants, surface hydrophobicity and flame-retardancy of the nanocomposites are easily varied to target properties by adjusting POSS structure, crosslink density, processing condition, etc. Investigations on the effects of POSS molecular geometry, composition, and concentration on physical and mechanical properties of resultant POSS-modified thermoplastic and thermosetting nanocomposites have been carefully reviewed in this article.

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