Studying the Effect of Fine Particles of Tungsten Carbide on the Macro-Structure, Hardness and Microhardness of Gradient Steel Billets

2020 ◽  
Vol 986 ◽  
pp. 3-8
Author(s):  
Andrey N. Anikeev ◽  
Ilia V. Chumanov ◽  
Vadim Sedukhin
Keyword(s):  
Tungsten Carbide ◽  
Fine Particles ◽  
Centrifugal Casting ◽  
High Hardness ◽  
Chemical Compositions ◽  
Steel Sheets ◽  
Dispersed Particles ◽  
Steel Castings ◽  
Scientists And Engineers ◽  
Single Material

Creating a gradient of properties in a single material is challenging for scientists and engineers. For this purpose, such methods are used as: welding of steels of different chemical compositions, joint rolling of steel sheets, sealing and surfacing of various kinds. All of these methods have a big disadvantage: under load, the material is destroyed in the weakest place - the place where the layers join. In this article, the authors proposed to obtain a gradient of properties in steel castings due to the introduction of dispersed particles of tungsten carbide into the crystallizing melt during centrifugal casting. The particles introduced serve as crystallization centers, accelerate the crystallization process and increase certain types of mechanical properties (hardness, microhardness, tensile strength). In addition, the particles of tungsten carbide have high hardness; therefore, in the structure of the workpieces they serve as reinforcing elements that strengthen the structure. The uneven distribution of particles in the preform being formed is possible for two reasons: tungsten carbide has a density greater than the melt, and besides, centrifugal force acts on them. The article describes the experiment and its results on the production of metal preforms with a gradient of properties. The introduced particles significantly influenced the macro-structure of the prepared castings. The article also presents the results of a study of the effect of particles on the hardness and micro-hardness of the resulting blanks.

Influence of dispersed particles of tungsten carbide on the microstructure of 12Kh18N10T steel obtained by centrifugal casting

2020 ◽  
pp. 68-73
Author(s):  
I. V. Chumanov ◽  
◽  
A. N. Anikeev ◽  
D. A. Zherebtsov ◽  
◽  
...  
Keyword(s):  
Heat Treatment ◽  
Tungsten Carbide ◽  
New Technologies ◽  
Centrifugal Casting ◽  
Neutron Radiation ◽  
Metal Structure ◽  
12Kh18n10t Steel ◽  
High Concentration ◽  
Metal Melt ◽  
Dispersed Particles

The development of new technologies in various industries, such as fast neuron reactors, require a new level of operational properties from steels and raise the issues of resistance to neutron radiation, radiation swelling, embrittlement and creep, and the level of residual activation. The principal way to increase these properties is to adjust the chemical composition, and rearrange the crystal structure of the metal. The authors propose to achieve this by introducing finely dispersed particles into the melt and controlled by them to “reinforce” the crystal lattice, grinding the metal structure. During the work, using the FactSage software package, thermodynamic modeling of the interaction of dispersed particles with a 18Х18Н10T steel melt was carried out, showing that the particles will interact with the metal melt, which can lead to their complete dissociation, and at the next stage of crystallization, regardless of the degree of dissolution of tungsten carbide, the formation of carbide phases based on titanium carbide with an FSS structure, as well as a carbide phase based on chromium carbide with the formula M23C3, will become. According to the simulation parameters, experiments were conducted, experimental blanks with different contents of the introduced tungsten carbide were obtained, and heat treatment was carried out. The study of microstructures showed that the introduced particles of tungsten carbide completely dissociate when interacting with a metal melt and contribute to an increase in ferrite in the microstructure of the workpiece. Studies of microhardness confi rmed the significant effect of the introduced carbide on the properties of the material: the maximum values of microhardness are achieved at a high concentration of refractory particles in the areas of their maximum concentration (outer edge of the workpieces). Carrying out heat treatment reduces microhardness, while aligning the gradient of properties with the volume of castings. This work was financially supported by the Ministry of Science and Higher Education of the Russian Federation within the framework of the federal target program under Agreement No. 075-15-2019-1711 (internal number 05.608.21.0276) dated December 04, 2019 (unique project identifier RFMEFI60819X0276).

Radiative effects and chemical compositions of fine particles modulating urban heat island in Nanjing, China

2021 ◽  
Vol 247 ◽  
pp. 118201
Author(s):  
Hao Wu ◽  
Tijian Wang ◽  
Qin'geng Wang ◽  
Yang Cao ◽  
Yawei Qu ◽  
...  
Keyword(s):  
Urban Heat Island ◽  
Fine Particles ◽  
Chemical Compositions ◽  
Heat Island ◽  
Radiative Effects ◽  
Urban Heat

Determination of Optimal Recrystallization Annealing Temperature on Structural Hot Dip Galvanized Steel Sheets

2011 ◽  
Vol 291-294 ◽  
pp. 860-863 ◽  
Author(s):  
Min Li Wang ◽  
Zhi Wang Zheng ◽  
Gong Ting Zhang
Keyword(s):  
Annealing Temperature ◽  
Production Condition ◽  
Salt Bath ◽  
Galvanized Steel ◽  
Recrystallization Temperature ◽  
Recrystallization Annealing ◽  
Chemical Compositions ◽  
Steel Sheets ◽  
The Stability ◽  
Optimum Annealing Temperature

The salt-bath annealing was used to study the recrystallization of structural steels as well as the effect of chemical compositions on the microstructure and properties of structural hot dip galvanized steel sheets was investigated in term with the production condition of the No.2 hot dip galvanizing line in Pangang. The optimum annealing temperature range was determined. Experimental results show that the recrystallization temperature of Grade40 and Grade33 is approximately 720°C and 680°C, respectively. Considering the stability of mechanical properties, their optimum annealing temperature are determined to be approximately 720°C. The recrystallization temperature of Grade50 is above 700°C. In order to ensure the margin of strength and the stability of properties of Grade50, the optimum annealing temperature is approximately 780°C.

scholarly journals Characteristics of PM2.5 Chemical Compositions and Their Effect on Atmospheric Visibility in Urban Beijing, China during the Heating Season

2018 ◽  
Vol 15 (9) ◽  
pp. 1924 ◽  
Author(s):  
Xing Li ◽  
Shanshan Li ◽  
Qiulin Xiong ◽  
Xingchuan Yang ◽  
Mengxi Qi ◽  
...  
Keyword(s):  
Fine Particles ◽  
Inorganic Ions ◽  
Water Soluble ◽  
Motor Vehicles ◽  
Urban Site ◽  
Chemical Compositions ◽  
Heating Season ◽  
Atmospheric Visibility ◽  
Visibility Impairment ◽  
Mass Concentrations

Beijing, which is the capital of China, suffers from severe Fine Particles (PM2.5) pollution during the heating season. In order to take measures to control the PM2.5 pollution and improve the atmospheric environmental quality, daily PM2.5 samples were collected at an urban site from 15 November to 31 December 2016, characteristics of PM2.5 chemical compositions and their effect on atmospheric visibility were analyzed. It was found that the daily average mass concentrations of PM2.5 ranged from 7.64 to 383.00 μg m−3, with an average concentration of 114.17 μg m−3. On average, the Organic Carbon (OC) and Elemental Carbon (EC) contributed 21.39% and 5.21% to PM2.5, respectively. Secondary inorganic ions (SNA: SO42− + NO3− + NH4+) dominated the Water-Soluble Inorganic Ions (WSIIs) and they accounted for 47.09% of PM2.5. The mass concentrations of NH4+, NO3− and SO42− during the highly polluted period were 8.08, 8.88 and 6.85 times greater, respectively, than during the clean period, which contributed most to the serious PM2.5 pollution through the secondary transformation of NO2, SO2 and NH3. During the highly polluted period, NH4NO3 contributed most to the reconstruction extinction coefficient (b′ext), accounting for 35.7%, followed by (NH4)2SO4 (34.44%) and Organic Matter (OM: 15.24%). The acidity of PM2.5 in Beijing was weakly acid. Acidity of PM2.5 and relatively high humidity could aggravate PM2.5 pollution and visibility impairment by promoting the generation of secondary aerosol. Local motor vehicles contributed the most to NO3−, OC, and visibility impairment in urban Beijing. Other sources of pollution in the area surrounding urban Beijing, including coal burning, agricultural sources, and industrial sources in the Hebei, Shandong, and Henan provinces, released large amounts of SO2, NH3, and NO2. These, which were transformed into SO42−, NH4+, and NO3− during the transmission process, respectively, and had a great impact on atmospheric visibility impairment.

scholarly journals Simultaneous Measurements of Chemical Compositions of Fine Particles during Winter Haze Period in Urban Sites in China and Korea

Atmosphere ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 292 ◽  
Author(s):  
Minhan Park ◽  
Yujue Wang ◽  
Jihyo Chong ◽  
Haebum Lee ◽  
Jiho Jang ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Fine Particles ◽  
Chemical Compositions ◽  
Aerosol Formation ◽  
Wind Speeds ◽  
Simultaneous Measurements ◽  
Dust Sources ◽  
Secondary Formation ◽  
Combustion Sources ◽  
Burning Coal

We performed simultaneous measurements of chemical compositions of fine particles in Beijing, China and Gwangju, Korea to better understand their sources during winter haze period. We identified PM2.5 events in Beijing, possibly caused by a combination of multiple primary combustion sources (biomass burning, coal burning, and vehicle emissions) and secondary aerosol formation under stagnant conditions and/or dust sources under high wind speeds. During the PM2.5 events in Gwangju, the contribution of biomass burning and secondary formation of nitrate and organics to the fine particles content significantly increased under stagnant conditions. We commonly observed the increases of nitrogen-containing organic compounds and biomass burning inorganic (K+) and organic (levoglucosan) markers, suggesting the importance of biomass burning sources during the winter haze events (except dust event cases) at both sites. Pb isotope ratios indicated that the fraction of Pb originated from possibly industry and coal combustion sources increased during the PM2.5 events in Gwangju, relative to nonevent days.

scholarly journals Size-segregated characteristics of organic carbon (OC), elemental carbon (EC) and organic matter in particulate matter (PM) emitted from different types of ships in China

2020 ◽  
Vol 20 (3) ◽  
pp. 1549-1564 ◽  
Author(s):  
Fan Zhang ◽  
Hai Guo ◽  
Yingjun Chen ◽  
Volker Matthias ◽  
Yan Zhang ◽  
...  
Keyword(s):  
Particle Size ◽  
Elemental Carbon ◽  
Fine Particles ◽  
Particle Mass ◽  
Fuel Oil ◽  
Chemical Compositions ◽  
Particle Sizes ◽  
Heavy Fuel Oil ◽  
Different Types ◽  
Marine Diesel

Abstract. Studies of detailed chemical compositions in particles with different size ranges emitted from ships are in serious shortage. In this study, size-segregated distributions and characteristics of particle mass, organic carbon (OC), elemental carbon (EC), 16 EPA polycyclic aromatic hydrocarbons (PAHs) and 25 n-alkanes measured aboard 12 different vessels in China are presented. The results showed the following. (1) More than half of the total particle mass, OC, EC, PAHs and n-alkanes were concentrated in fine particles with aerodynamic diameter (Dp) < 1.1 µm for most of the tested ships. The relative contributions of OC, EC, PAH and alkanes to the size-segregated particle mass are decreasing with the increase in particle size. However, different types of ships showed quite different particle-size-dependent chemical compositions. (2) In fine particles, the OC and EC were the dominant components, while in coarse particles, OC and EC only accounted for very small proportions. With the increase in particle size, the OC / EC ratios first decreased and then increased, having the lowest values for particle sizes between 0.43 and 1.1 µm. (3) Out of the four OC fragments and three EC fragments obtained in thermal–optical analysis, OC1, OC2 and OC3 were the dominant OC fragments for all the tested ships, while EC1 and EC2 were the main EC fragments for ships running on heavy fuel oil (HFO) and marine-diesel fuel, respectively; different OC and EC fragments presented different distributions in different particle sizes. (4) The four-stroke low-power diesel fishing boat (4-LDF) had much higher PAH emission ratios than the four-stroke high-power marine-diesel vessel (4-HMV) and two-stroke high-power heavy-fuel-oil vessel (2-HHV) in fine particles, and 2-HHV had the lowest values. (5) PAHs and n-alkanes showed different profile patterns for different types of ships and also between different particle-size bins, which meant that the particle size should be considered when source apportionment is conducted. It is also noteworthy from the results in this study that the smaller the particle size, the more toxic the particle was, especially for the fishing boats in China.

Design of High-Efficient Bits for Igneous Rock in Xushen Gasfield

2013 ◽  
Vol 385-386 ◽  
pp. 308-311
Author(s):  
Li Gang Zhang ◽  
Tie Yan ◽  
Shi Bin Li
Keyword(s):  
Tungsten Carbide ◽  
Design Method ◽  
Polycrystalline Diamond ◽  
High Hardness ◽  
Rake Angle ◽  
Gas Field ◽  
Working Face ◽  
High Efficient ◽  
Low Efficiency ◽  
Bit Life

The igneous rocks in deep formations of the Xushen gasfield have the following characters: high abrasive property, high hardness, and high drillability, which lead to many drill bit accidents, few footage per bit , low efficiency of drilling, long drilling cycle, these severely restrict the exploration and development process of gas field. According to the features of deep formation, a hybird cutters bit is designed. It has three cones, with the overhang cone , duplicate taper and offset cone characters. The tungsten carbide cutters and the polycrystalline diamond compacts cutters are alternative collocation in the same tooth row in the bit. The exposed height of the tungsten carbide cutters is higher than polycrystalline diamond compacts cutters. The back rake angle of polycrystalline diamond compacts cutters is 10 ~ 40 °, the side rake angle is 10 ~ 30 °. The normal direction of working face stay the same with the composite slip direction, and the side rake pointed at adjacent gullet. Through the design method, it is integrated that the advantages of roller bit and PDC bit, the way of impact breakage and rotational shear breakage and the prominent performance of tungsten carbide cutters and polycrystalline diamond compacts cutters. It can improveROP and bit life.

Effects of Complexing Agent Concentration and Bath pH on Electroless Nickel Deposition for Tungsten Carbide Powders

2014 ◽  
Vol 970 ◽  
pp. 240-243 ◽  
Author(s):  
Pranee Rattanawaleedirojn ◽  
Kanokwan Saengkiettiyut ◽  
Yuttanant Boonyongmaneerat ◽  
Nutthita Chuankrerkkul ◽  
Sawalee Saenapitak
Keyword(s):  
Tungsten Carbide ◽  
Deposition Rate ◽  
Electroless Nickel ◽  
Powder Injection ◽  
Complexing Agent ◽  
Chemical Compositions ◽  
High Deposition Rate ◽  
Nickel Deposition ◽  
Moulding Process ◽  
Injection Moulding Process

An elemental nickel (Ni) or cobalt (Co) is typically introduced to tungsten carbide (WC) prior to powder injection moulding process (PIM) for hard metal fabrication to enhance toughness and tool life. Mixing of powders is normally practiced, although it requires a long processing time for homogeneous mixing. In this study, as an alternative method, an addition of Ni via the electroless deposition method is investigated. The key process parameters, including the concentration of the complexing agent, namely sodium citrate, and bath pH, are systematically examined in relation to deposition rate and deposits size, microstructure, and chemical compositions. As the bath pH is increased to higher alkalinity of 10 and the Ni ion to complexing agent mole ratio is controlled under 1:1, a stable electroless nickel solution and a relatively high deposition rate with about 15% weight gain for 1 hour deposition duration are achieved. The phosphorus (P) content, obtained in the range of 5-9 wt%, is largely influenced by the bath pH. While a rapid deposition rate is associated with preferentially deposition of Ni on pre-deposited Ni sites, a low to moderately high deposition rate results in more uniform incorporation of Ni-P alloys in WC powder mixture.

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